International CT colonography standards

Recently published in Clinical Radiology, a journal of the UK Royal College of Radiologists, is a contribution by the International Collaboration for CT Colonography Standards [ 1 ]. The group comprises 28 radiologists and radiographers based primarily in the UK and Canada, but with single members representing Europe, Australasia, Korea and Japan. Working since mid-2008, this group assessed the scientific evidence on CT colonography and reported their findings and recommendations in a set of standards, approved by all parties in January 2010. The Canadian Association of Radiologists has made these recommendations publicly available [ 2 ].
The detailed 44-page paper deals with all possible aspects of running a CT colonography service, from informing patients about the procedure and choosing scanner settings to interpreting images and monitoring the performance of the CT colonography team. An interesting feature of the document is that, for each of the dozen different sections, descriptive text is accompanied by a list of performance standards—both those minimally accepted and those considered “best practice”. An added value is found in the appendices, two of which consist of information sheets for patients that can be adapted for use by any medical center. In particular, one appendix provides general procedural information in simple terms while another gives detailed instructions on bowel preparation with tagging. Adaptation of this second tool for use in non-Anglophone countries will require localization regarding commonly available foods for a low-residue diet.

References

1. Burling D.; International Collaboration for CT Colonography Standards (2010)  CT colonography standards. Clin Radiol 65(6):474-480
   
2. (2010) CAR CT colonography standards. Canadian Association of Radiology, Ottawa, January 2010
   

Safety of imaging debated in leading general medical journals

This summer, numerous editorials and commentaries have appeared in specialist and general medical journals alike on the safe and appropriate use of medical imaging procedures involving ionizing radiation. Many of these articles refer to radiological practices in the USA, where hundreds of cases of accidental radiation overdose during CT have been reported.
In a “perspective” published in the New England Journal of Medicine [ 1 ], Smith-Bindman from the University of California at San Francisco criticized the lack of a nation-wide body to monitor patients' radiation exposure as well as the absence of guidelines as to what doses “are reasonable or achievable” for various CT examinations. Acknowledging the great clinical value of CT (as well as its risks), she offered four strategies for guaranteeing CT safety: lower the radiation dose associated with each type of examination, monitor actual exposures, educate referring physicians and radiological technicians about dose control, and reduce the number of referrals for CT.
Similar issues were raised by Brenner and Hricak, based in New York and writing on the pages of JAMA [ 2 ]. Noting the paradox in which occupational exposure to ionizing radiation is strictly regulated but medical exposure is not, these authors contemplated the advantages of governmental legislation to ensure quality and safety. Currently, in the USA, standardized, coast-to-coast use of X-ray machines has only been implemented for mammography (whereas across Europe a single 1997 EU directive regulates medical radiation exposure). Federal rules could establish parameters for quality control, guide educational programs for physicians who prescribe radiographic studies, and provide decision-making tools to help abate the problem of overprescribed CT examinations. The authors nonetheless acknowledged that legislating on clinical practice is a delicate issue that must be done with care and sensitivity to the continual advances in the medical evidence-base.

References

1. Smith-Bindman R. (2010) Is computed tomography safe?. N Engl J Med 363:1-4
   
2. Brenner DJ, Hricak H. (2010) Radiation exposure from medical imaging. Time to regulate? . JAMA 304:208-209
   

Selected literature update
Cardiothoracic MDCT: two new books from Springer

Springer recently published two books on cardiothoracic CT.
The first volume, called Integrated Cardiothoracic Imaging with MDCT, was edited by Martine Rémy-Jardin and Jacques Rémy. Published in 2009, the book is an international effort with contributions from across Europe, North America and China. This book integrates knowledge from two distinct fields, namely thoracic radiology and cardiac radiology. It considers heart-lung interplay in physiological and pathological situations and discusses imaging applications and findings when cardiac pathology has thoracic complications, and vice versa. Selected for MDCT.net's literature archive are the chapters on technological issues.
The second volume, Cardiac CT Imaging, will be available in print later this year. Now in its second edition, the book was edited by Matthew J. Budoff and Jerold S. Shinbane and contains contributions from radiologists working in the USA and Germany. It addresses CT assessment of coronary calcium, CT angiography of the coronaries, great vessels and peripheral vasculature, the use of CT angiography to study heart pathology, and the integration of CT with other imaging and interventional procedures for cardiovascular disease. Of the two chapters in MDCT.net, one describes technical aspects of CT scanners relative to cardiac imaging and the other reviews radiation dosimetry and current protocols for dose reduction.

A new International Society for Computed Tomography

After years of success as an annual CME event, the International Symposium on Multidetector Row CT has now grown into a distinct professional association. The decision to separate from its sponsor, Stanford University, reflects both the need for an independent organization, due to the size and complexity of the meeting, and the current climate in the US against industry sponsorship of medical education.
The new association, called International Society for Computed Tomography (ISCT), represents the first medical society dedicated to this imaging modality in all its clinical aspects. ISCT is guided by the course's directors, namely Geoffry Rubin and Gary Glazer, both at Stanford University in Palo Alto, USA, and Maximilian Reiser from Ludwig-Maximilians University in Munich, Germany. It will continue to hold the International Symposium each year in California and will also begin running a similar biannual program in Garmisch, Germany, called Internationales Symposium Mehrschicht CT, previously sponsored by the Institute for Clinical Radiology, University of Munich. Information about these programs is available at www.isct.org.org.

Expert statement on coronary CT angiography from eight North American medical and radiological societies

tIn the past several years, coronary CT angiography has been the subject of numerous systematic reviews and expert statements but, given the rapid advances in technology and clinical insight in this field, new overviews are always welcome. This month, three journals – Circulation [ 1 ], Journal of the American College of Cardiology, and Catheterization and Cardiovascular Interventions – jointly published an expert consensus document written by a task force of the American College of Cardiology Foundation (ACCF) and sponsored by the American Heart Association (AHA) and six other, mostly American societies of radiology and cardiovascular medicine.
As indicated in the preamble of the text, expert consensus statements are prepared when there is not enough evidence for writing a clinical practice guideline according to the rigorous ACCF-AHA criteria.  This new statement was prepared by a panel of experts representing the eight societies involved; additional members of these societies served as peer reviewers before the text was approved in November 2009.
The document, addressed to practicing physicians, reviews current and developing applications for coronary CT angiography in patients with diagnosed or suspected coronary artery disease. The emphasis is on 64-slice MDCT, as earlier CT scanners are inadequate for cardiac imaging while, for the newest models, there is limited evidence on which to base a consensus. The 36-page document begins with an executive summary, a technological review, and an overview of fundamental concepts of cardiac imaging. Then follow three sections on clinical applications that summarize established uses, emerging methods, and applications for which no consensus could be reached; this latter part deals with extracardiac findings, the use of CT angiography in high-risk patients, and the “triple-rule out” protocol for emergency room use. The last three sections focus on safety (radiation and contrast medium), costs, and quality in diagnostic images.
As usual for any ACCF-AHA document, after an abundant list of references we find details of the corporate and institutional relationships of authors and peer reviewers.  Roles such as consultant, speaker, share holder, expert witness and board member are indicated, as is the receipt of funding for research.

References

1. Mark DB, Berman DS, Budoff MJ et al. (2010)   ACCF/ACR/AHA/NASCI/SAIP/SCAI/SCCT 2010 Expert Consensus Document on Coronary Computed Tomographic Angiography. A Report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents. Circulation. 2010 May 17. [Epub ahead of print]
   

Contrast-enhanced MDCT in the diagnostic workup of patients with embolic disease

Two single-center studies, recently added to MDCT.net's full text archive, examined the utility of contrast-enhanced MDCT in diagnosing embolic disease.
Researchers at Malmö University Hospital, Sweden, focused on patients hospitalized for acute thromboembolic occlusion of the superior mesenteric artery [ 1 ]. Of the 67 patients retrospectively studied, 36 had undergone 16-slice MDCT with intravenous administration of contrast medium, 10 had had non-enhanced MDCT, and 21 had no CT examination. Revascularization procedures were performed more frequently in patients who had contrast-enhanced MDCT, and this was associated with improved survival: the in-hospital mortality rate in this group was 42%, while it was 90% among patients who had non-enhanced MDCT and 71% among patients who did not have CT. The authors concluded that contrast-enhanced MDCT should be performed in all patients with acute abdomen to help vascular surgeons prepare adequate treatment.
A study from Seoul National University Bundang Hospital, Korea, focused on patients with acute ischemic stroke in whom an embolic cause was suspected but not documented [ 2 ]. They identified 50 such patients who had also undergone contrast-enhanced 64-slice cardiac MDCT, and retrospectively examined the prevalence of signs of atherosclerotic disease in the ascending aorta and aortic arch. Compared to a group of 106 patients diagnosed with non-embolic stroke, patients with “possibly embolic” stroke had higher rates of thrombus and ulcerated plaque, had thicker plaque, and were more frequently classified as having high-risk aortic atherosclerotic disease. The authors concluded that MDCT can reveal cardioembolic sources in stroke patients and reduce the rate of diagnoses of stroke of undetermined etiology, thereby facilitating the implementation of specific treatments.

References

1. Wadman M., Block T., Ekberg O. et al. (2010) Impact of MDCT with intravenous contrast on the survival in patients with acute superior mesenteric artery occlusion. Emerg Radiol 17(3):171-178
   
2. Ko Y., Park JH, Yang MH et al. (2010) Significance of aortic atherosclerotic disease in possibly embolic stroke: 64-multidetector row computed tomography study. J Neurol 257(5):699-705
   

Clinical risks and benefits of cardiac imaging with ionizing radiation: a discussion on the pages of iJACC

The May 2010 issue of JACC: Cardiovascular Imaging (iJACC) includes a series of papers that discuss the health risks from radiation exposure during cardiac CT in light of the clinical benefits provided by this procedure. The lead paper in the series is a state-of-the-art review on cancer risk, contributed by Laskey et al. from the US and Germany [ 1 ]. The paper explains how low levels of radiation can induce cancer, according to the linear no-threshold theory, but also stimulate bodily defences against cancer induction, according to the process of adaptive protection (radiation hormesis). This review is accompanied by two invited editorials on the risk-benefit balance in cardiac CT and the importance of proper clinical decision-making [ 2, 3 ].
The series is introduced on the “editor's page” by a passionate commentary by ten cardiologists and radiologists from the US and Germany [ 4 ], who point out “critical deficiencies ... in the quality of the evidence” regarding the use of radiation in cardiac imaging. Shaw and colleagues deplore the “lack of progress on dose measurement and cancer risk estimation and the lack of standards for evaluating the risks and benefits of cardiac imaging.” They therefore call for “considerably more research” to permit the development of new or better methods to measure radiation dose, categorize dose on scales that correspond to risk and typical exposures during imaging, extrapolate from high- to low-dose exposures, and estimate cancer risk in particular clinical groups. Research is also needed to compare the relative effectiveness of ionizing and nonionizing procedures in different clinical situations. Finally, they recommend the production of new practice guidelines to ensure proper clinical decision-making as well as websites to educate patients about cardiac CT. Altogether, this iJACC series stimulates much reflection on current cardiac CT practices and future directions.

References

1. Laskey WK, Feinendegen LE, Neumann RD, Dilsizian V. (2010) Low-level ionizing radiation from noninvasive cardiac imaging: can we extrapolate estimated risks from epidemiologic data to the clinical setting?. J Am Coll Cardiol Img 3:517-524
   
2. Gerber TC, Gibbons RJ (2010) Weighing the risks and benefits of cardiac imaging with ionizing radiation. J Am Coll Cardiol Img 3:528-535
   
3. Halliburton S., Schoenhagen P. (2010) Cardiovascular imaging with computed tomography: responsible steps to balancing diagnostic yield and radiation exposure.J Am Coll Cardiol Img 3:536-540
   
4. Shaw LJ, Achenbach S., Chandrashekhar Y. et al. (2010) Imaging modalities and radiation: benefit has its risks.... J Am Coll Cardiol Img 3:550-552
   

Give a Scan: a public database of CT, MR and US images and clinical data, populated by patients with lung cancer

In a unique step of empowering patients to drive clinical research, the Lung Cancer Alliance (LCA) launched an online database of lung cancer images and related clinical data, voluntarily provided by patients themselves. The database, called Give a Scan (www.giveascan.org) , is designed to provide researchers with a large dataset useful for retrospective study of lung cancer screening and staging, treatment evaluation, and development of computer-assisted methods of diagnosis.
The database will collect anonymized CT, MR and US images and videoclips from patients, who will be protagonists in terms of deciding to participate, obtaining electronic image data (in DICOM format) from their healthcare providers, and submitting this material and other clinical data to the LCA for online posting. The direct involvement of patients frees researchers from tedious tasks of data management, simplifies issues related to privacy, and guarantees creation of a population-wide database not limited to one hospital or clinical subgroup.
The database went live in June 2010 and is just being populated. Researchers can access the data at no cost, but are asked to acknowledge the source of the data in any resulting publications.

Contrast-induced nephropathy in the emergency room

Latest data from the US indicate that, in 2006, iodinated contrast medium was used 179 thousand times in patients seen in outpatient and emergency departments, corresponding to about 0.1% of all ambulatory visits [ 1 ]. In this heterogeneous population, the incidence of contrast-induced nephropathy (CIN) had previously been estimated from retrospective studies involving subgroups of patients at risk. Therefore, researchers from the USA prospectively assessed CIN incidence and clinical impact in an unselected urban population seen in the emergency department.
The study, published in the Clinical Journal of the American Society of Nephrology [ 2 ], enrolled 633 adults who received intravenous contrast medium for 64-slice MDCT for any emergency evaluation; patients with known kidney disease and the critically ill were excluded from study. CIN was defined as an increase in serum creatinine ≥0.5 mg/dl or ≥25% in the 2-7 days after receiving contrast medium.
CIN developed in 70 cases (11%; 95% CI, 9%-14%) and led to severe renal failure in 6 patients. Renal failure resulted in death in 4 cases, and 2 other patients with CIN also died, for an all-cause mortality rate of 9%. In contrast, mortality among patients without CIN was 2%. Compared to the non-CIN group, patients with CIN had higher rates of congestive heart failure, diabetes and vascular disease but similar rates of baseline renal insufficiency.
The authors concluded that, in an urban emergency room setting, the rate of CIN is higher than previously estimated. In this relatively young, heterogeneous population, CIN can lead to severe renal failure and death, even after several days. They expressed concern that, in this setting, traditional CIN risk factors may not be sufficient for screening patients, who may have undiagnosed kidney pathology due to untreated diseases such as hypertension and hyperglycemia.

References

1. Schappert SM, Rechtsteiner EA (2008)   Ambulatory medical care utilization estimates for 2006. Natl Health Stat Report (8):1-29
   
2. Mitchell AM, Jones AE, Tumlin JA, Kline JA (2010) Incidence of contrast-induced nephropathy after contrast-enhanced tomography in the outpatient setting. Clin J Am Soc Nephrol 5:4-9
   

Selected literature update
Focus on pancreatic imaging

In stark contrast to the liver, in which diagnostic imaging has clearly delineated the dual vasculature and segmental anatomy, the imaging appearance of the pancreas is poorly characterized. Thus, the Chinese character for pancreas, “organ of remote region or unexplored territory”, aptly applies to current knowledge of the pancreatic vasculature and lymphatic network [ 1 ]. With this comment, Prof. H. Mori of the Department of Radiology, Oita University (Oita, Japan) opened the Feature Section in the latest issue of Abdominal Imaging.
The special section comprises seven articles contributed by Mori and colleagues; three articles involving MDCT technology have been selected for inclusion in the literature archive of MDCT.net. One study characterized the anatomy of intra- and peripancreatic veins in 42 patients, using triple-phase 16-slice MDCT [ 2 ]. Another used 16- or 32-slice MDCT to characterize peripancreatic lymphatics in healthy subjects and in patients with pancreatic carcinoma [ 3 ]. In healthy persons lymphatics appeared as thin lines contiguous with the lymph nodes, but in carcinoma patients they were described as tubular, reticular or like a soft tissue mass. These two imaging studies provide the first CT descriptions of pancreatic veins and lymphatics and, together with other articles in this issue, make a step forward in defining the normal and pathological imaging appearances of this organ. This knowledge is essential for an early diagnosis and accurate staging of pancreatic cancer, to support treatment decisions and to ultimately reduce the high mortality from this disease.

References

1. Mori H. (2010) New insight of pancreatic imaging: from "unexplored" to "explored". Abdom Imaging 35(2):130-133
   
2. Hongo N., Mori H., Matsumoto S. et al. (2010) Anatomical variations of peripancreatic veins and their intrapancreatic tributaries: multidetector-row CT scanning. Abdom Imaging 35(2):143-153
   
3. Sai M., Mori H., Kiyonaga M. et al. (2010) Peripancreatic lymphatic invasion by pancreatic carcinoma: evaluation with multi-detector row CT. Abdom Imaging 35(2):154-162
   

SharpView CT: a tool for enhancing CT datasets that may facilitate low-radiation imaging

There is currently great interest in developing effective low-radiation CT imaging protocols. Since a reduction in X-ray tube current or voltage is accompanied by an increase in noise, additional steps must be taken to obtain diagnostic-quality images. This might involve, for example, an increase in the iodine concentration of the contrast medium [ 1 ] or the use of image elaboration software after data acquisition. SharpView CT is one such software tool for image enhancement that may find clinical application in low-radiation CT.
Produced by SharpView, a company based in Linköping, Sweden, the software SharpView CT is an independent application that can be installed on any computer and that automatically elaborates CT images without manual intervention. The software works by applying general operatore process (GOP) technology. GOP is a 2D adaptive, non-linear filter that eliminates random noise by examining different-sized areas around each pixel to identify pixels that belong to the structure imaged. This filtering approach, developed by the Swedish company Context Vision, mimics human vision in searching for patterns. The software then suppresses noise and enhances edges, thereby improving image quality.
The first clinical experiences using SharpView CT for low-radiation imaging are now being published. One retrospective study evaluated the quality of 16-slice abdominal CT images obtained at high and low current, without and with filtering [ 2 ]. SharpView CT substantially reduced noise but gave mixed results in image quality, suggesting the need for optimization. A prospective study, presented this May at the American Roentgen Ray Society meeting, found that SharpView CT reduced noise and increased diagnostic confidence of both low- and standard-dose CT of the abdomen and chest [ 3 ]. In the coming future, the radiological literature should offer additional reports on the possibility of using image enhancement tools like SharpView CT to facilitate low-radiation CT imaging.

References

1. Iezzi R., Cotroneo AR, Giammarino A. et al. (2010) Low-dose multidetector-row CT-angiography of abdominal aortic aneurysm after endovascular repair. Eur J Radiol [Epub ahead of print]
   
2. Leander P., Söderberg M., Fält T. et al. (2010) Post-processing image filtration enabling dose reduction in standard abdominal CT. Radiat Prot Dosimetry 139(1-3):180-185
   
3. Singh S., Kalra M., Sharma A. et al. (2010) Prospective evaluation of effect of 2D adaptive filters on low radiation dose chest and abdominal CT. Presented at: 2010 annual meeting of the American Roentgen Ray Society, San Diego
   

American Roentgen Ray Society meets in San Diego

The 110th annual meeting of the radiology society named after the discoverer of X-rays, Nobel Laureate Wilhelm Röentgen, was held in San Diego last May. The American Roentgen Ray Society (ARRS), the oldest US radiology society, serves a mission of advancing “medicine through the science of radiology and its allied sciences”. These goals are reached by publication of the monthly American Journal of Roentgenology and its quarterly supplement AJR Integrative Imaging, as well as through the annual scientific and educational meeting.
The ARRS annual meeting is presented as a CME event comprising a three-day categorical course, a case-based imaging review course, instructional courses, symposia, scientific presentations and exhibits. Compared to the large meetings of the European Society of Radiology and the Radiological Society of North America, this is an intimate meeting hosting 2000 radiologists. This year's meeting theme was the “appropriate use of imaging in the wide spectrum of diseases”, emphasizing the evidence base of decision making. Thus, the categorical course theme was “Practical approaches to common clinical conditions: efficient imaging (PAC3E) – setting the PAC3E of imaging”. More information about the ARRS and its next annual meeting is available online at www.arrs.org.

ESR position statements available in I ³

Insights into Imaging (I3), the new journal of the European Society of Radiology (ESR), was created as a platform for distributing society documents, guidelines and educational reviews. The first issue of I3 has already mets its editorial objectives with the publication of a trio of statements signed by the ESR itself.
One paper assessed the changing role of radiology in today's healthcare system and offered recommendations for the training of radiologists and for the optimization of relationships among radiologists, clinicians and patients [ 1 ]. This descriptive paper was accompanied by a more technical one [ 2 ] on the ideal organization of diagnostic imaging and interventional radiology units; this second paper was based on the arguments already expressed by G.P. Krestin of the University Medical Center Rotterdam [ 3 ]. A third paper continued the thread on the organization of radiology departments by describing procedures for clinical audit, i.e. internal evaluation of the quality of care in order to guide efforts for improvement [ 4 ].
Other titles published in this first issue include an ESR position paper on ultrasonography and a joint ESR-European Association of Nuclear Medicine survey on the practice of multimodal imaging across Europe. Already the first papers for the second issue of I ³ have been published “ online first” by Springer.

References

1. ESR (2010)  The future role of radiology in healthcare. Insights Imaging 1(1):2-11
   
2. ESR (2010) The professional and organizational future of imaging. Insights Imaging 1(1):12-20
   
3. Krestin GP (2009) Maintaining identity in a changing environment: the professional and organizational future of radiology. Radiology 250(3):612-627
   
4. ESR (2010) Clinical audit—ESR perspective. Insights Imaging 1(1):21-26
   

Selected literature update
CT colonography: recent research

The latest issue of European Radiology contains two research reports on CT colonography protocols and applications, both selected for inclusion in MDCT.net's full text archive.
Researchers from Sweden investigated differences in image quality achieved with standard and low-dose imaging protocols [ 1 ]. In the study, 48 consecutive patients at risk of colorectal cancer underwent 64-slice CT colonography with both standard settings (40-160 mA) and automatic dose modulation (10-50 mA), followed by optical colonoscopy the same day. CT images were viewed in filet view, in which the colonic turns are virtually unrolled to permit flat viewing of the lumenal surface. Low-dose images were assessed with and without manipulation of opacity levels to remove “ snow” artifacts. Therefore, for each patient, three sets of images (standard, modified low dose, original low dose) were scored for noise artifacts and quality. The low-dose protocol achieved a 73% reduction in radiation exposure, but this was accompanied by an equivalent increase in total image noise. Both sets of low-dose images had more cobblestone and snow artifacts as well as more irregularly delineated folds, resulting in a significant loss in sensitivity for small polyps (from 82.4% for standard images, to 67.2% and 62.4% for the modified and original low-dose images, respectively). However, for larger polyps (≥6 mm), the loss in sensitivity was not significant (from 86.7% to 81.9% and 77.1%, respectively).
In the second report [ 2 ], researchers from the United Kingdom investigated the value of CT colonography in detecting synchronous lesions, i.e. additional colonic lesions in patients already diagnosed with colorectal cancer. The researchers retrospectively evaluated CT images from 165 patients in whom data from sigmoidoscopy, colonoscopy or histology were also available. Of the 41 synchronous lesions (≥6 mm) identified by the gold standard examination, 33 were found with CT colonography (per-polyp sensitivity, 80.5%). CT colonography identified 3 additional lesions but also gave 6 false positives (per-patient specificity, 95.5%). The authors suggested that this imaging modality could be useful in the pre-operative workup, not only to stage known disease but also to search for additional lesions that could be simultaneously removed.

References

1. Fisichella VA, Bath M., Allansdotter Johnsson A. et al. (2010) Evaluation of image quality and lesion perception by human readers on 3D CT colonography: comparison of standard and low radiation dose. Eur Radiol 20(3):630-639
   
2. McArthur DR, Mehrzad H., Patel R. et al. (2010) CT colonography for synchronous colorectal lesions in patients with colorectal cancer: initial experience. Eur Radiol 20(3):621-629
   

Monitoring radiation exposure with an iPhone applet

The population's exposure to ionizing radiation from diagnostic and interventional imaging procedures has increased over the past few decades, and this has stimulated a recent increase in interest in monitoring total exposure and understanding the related cancer risk. For this reason, M.O. Baerlocher, a radiologist at the University of Toronto, and Tidal Pool Software (Victoria, Canada) developed a novel applet (a software module, or small application) for iPhone and iPod Touch devices.
The applet, called Radiation Passport, permits patients to record the type and date of every medical imaging examination they undergo. For each examination, the application assigns a dose of radiation taken from a database of procedures and typical exposures; the patient can alternatively insert a custom dose value. The application also estimates cancer risk for individual procedures as well as for the cumulative exposure. A German language version is available as well.
Radiation Passport is designed to promote awareness among patients about the association between radiation and cancer risk and to help them decide whether to undergo imaging examinations proposed by physicians. Access to such detailed information may confuse some patients and lead them to refuse needed examinations, and radiologists may be frustrated by patients who are armed with information they do not fully understand. Nonetheless, in the long term, the availability of tools of this sort should result in greater appreciation of the risks and benefits of medical imaging. The tool may also help radiologists explain the value of particular procedures to patients.
The developers of Radiation Passport have recently described the radiological and clinical aspects of  their applet in the Journal of the American College of Radiology. Commercial information is available from www.tidalpool.ca.

Clinical and cost benefits of coronary CT angiography: state of the art review

Last year, the Society of Cardiovascular Computed Tomography published practice guidelines on performing, interpreting and reporting the results of coronary CT angiography (CTA) (reviewed in MDCT.news of May and June 2009; [ 1, 2 ]). Nonetheless, in this new and rapidly expanding field, there is still debate as to the best clinical use and cost effectiveness of coronary CTA in the diagnosis of coronary artery disease (CAD). Therefore, Min and colleagues from three US cities reviewed the literature to assess the clinical and cost benefits of 64-slice CTA in evaluating patients with suspected CAD [ 3 ].
This traditional review, published in the Journal of the American College of Cardiology, summarized recent studies on the accuracy of coronary CTA for diagnosing obstructive CAD and myocardial ischemia, its use in the evaluation of patients with acute chest pain and in the stratification of those with stable pain, and its cost effectiveness. The authors noted that both opponents and advocates of a wider adoption of this imaging modality use the same data to support their arguments regarding the diagnostic, prognostic, economic and safety features of CTA. They concluded by acknowledging the high value of CTA in detecting or excluding CAD, but state that strong evidence is still needed to define its safety, cost-benefit relationship, and ability to predict clinical outcomes and to guide treatment decisions.

References

1. Abbara S., Arbab-Zadeh A., Callister TQ et al. (2009) SCCT guidelines for performance of coronary computed tomographic angiography: A report of the Society of Cardiovascular Computed Tomography Guidelines Committee. J Cardiovasc Comput Tomogr 3(3):190-204
   
2. Raff GL, Abidov A., Achenbach S. et al. (2009) SCCT guidelines for the interpretation and reporting of coronary computed tomographic angiography. Society of Cardiovascular Computed Tomography. J Cardiovasc Comput Tomogr 3(2):122-136
   
3. Min JK, Shaw LJ, Berman DS (2010) The present state of coronary computed tomography angiography: a process in evolution. J Am Coll Cardiol 55:956-965
   

I ³: a new periodical from ESR

Insights into imaging is the latest periodical from the European Society of Radiology (ESR). This new electronic publication, edited by Robert Hermans (Leuven) and published by Springer Verlag, was launched in January 2010. The journal, nicknamed I ³, carries the revealing subtitle “education and strategies in European radiology”. Its scope is to complement the research-oriented European Radiology by emphasizing the publication of pictorial reviews, best-practice reports, educational reviews, practice guidelines and policy statements of the ESR. Abstracts of the 2010 European Congress of Radiology have been published in a supplement to the first issue of the journal.
Insights into imaging is available through the Springer platform at no cost to ESR members who access through the myESR.org user area. Selected papers are also freely available to all readers on the journal's website (www.i3-journal.org).

ACR data registries: auditing tools to promote quality and drive research

The National Radiology Data Registry (NRDR) is a set of databases collecting information on radiological practices and patient outcomes for imaging facilities across the United States. Maintained by the American College of Radiology (ACR), these databases are designed to facilitate auditing of the performance of imaging facilities and of individual radiologists, by comparison with similar facilities regionally and nationally.
The NRDR portal currently provides password-protected access to 5 registries. The National Oncologic PET Registry (NOPR) was activated in 2005. In 2009, the ACR launched three additional registries: the CT Colonography Registry, the General Radiology Improvement Database (GRID), the National Mammography Database Registry. A dose index registry is expected to be activated this year. In addition, the NRDR portal provides access to a database of a joint ACR-Society of Uroradiology project called IV Contrast Extravasation (ICE).
Participation in the ACR data registries is voluntary, involves the payment of an annual fee, and is limited to imaging sites within the US and its territories. Participating sites benefit by receiving twice-yearly reports that document the quality of the services offered and permit assessment of the efficacy of quality improvement programs. Data collected nationally will be used to determine the effectiveness of specific radiological procedures and thus will promote evidenced-based radiology.

Noncontrast MDCT for appendicitis: a systematic review

Appendicitis, a common cause of acute abdomen often requiring immediate surgery, remains difficult to diagnose and many patients undergo appendectomy unnecessarily. Since a clinical diagnosis is not specific, abdominal CT is the preferred diagnostic method and numerous CT protocols using oral, rectal or intravenous contrast medium have been developed. Nonetheless, in hectic emergency departments, the use of noncontrast CT can be advantageous. Therefore, researchers from New York and Michigan did a systematic review to determine if noncontrast CT was sufficiently accurate in this emergency setting [ 1 ].
The analysis included 7 studies that reported the diagnostic accuracy of noncontrast MDCT, compared to a reference standard (i.e. surgical findings or long-term clinical follow-up), in adults presenting with suspected appendicitis. Studies that included children were excluded, as were numerous others that did not report patients' ages or length of clinical follow-up. According to the reference diagnostic method, 20.1%-84.5% of enrolled patients had appendicitis. In these studies, sensitivity of noncontrast CT for diagnosing appendicitis ranged from 87% to 97% and specificity from 92% to 100%. Pooled estimates of sensitivity and specificity were 92.7% and 96.1%, and the positive and negative likelihood ratios were 24 and 0.08, respectively.
The diagnostic accuracy estimated by this systematic review was considered by the authors to be adequate for guiding clinical decisions in emergency room settings. However, given the estimated 7.3% false-negative rate, they stressed that CT findings – like all diagnostic findings – be evaluated in light of each patient's clinical conditions. They also emphasized the need for complete reporting of clinical data, so that more studies can be included in systematic reviews. Finally, observing that inconclusive CT examinations are inconsistently reported, they noted a need for research on how to manage patients with suspected appendicitis when CT findings are not diagnostic. This article has been selected for discussion in the Annals of Emergency Medicine's Journal Club. For this purpose, the journal has posed a series of questions about the paper [ 2 ]. Answers will become available in June of this year.

References

1. Hlibczuk V., Dattaro JA, Jin Z. et al. (2010) Diagnostic accuracy of noncontrast computed tomography for appendicitis in adults: a systematic review. Ann Emerg Med 55(1):51-59
   
2. Schriger DL, Reynolds TA (2010) Annals of Emergency Medicine Journal Club. Journal club: the conduct and reporting of meta-analyses of studies of diagnostic tests, and a consideration of ROC curves. Ann Emerg Med 55(1):60-61
   

ECR 2010: a congress designed to create virtuosos in radiology

The theme of the 2010 European Congress of Radiology (ECR), held this year like every year in Vienna, was virtuosity in radiology.  A virtuoso has masterly skill and technique in the arts, and so the choice of this theme was most suited for the European Society of Radiology (ESR), a society whose mission, according to ECR President M. Szczerbo-Trojanowska, is “to promote the highest quality radiology based on science and education”.
The five-day program was certainly rich in science and education, as it offered attendees a choice of 260 conference sessions, 1500 oral presentations and 3300 electronic posters, worth a total of 27 hours of continuing medical education. Attendance was impressively high, with over 19 000 persons from almost 100 nations worldwide. Although the most attendees came Austria and neighboring countries Italy and Germany (1000 participants each), numerous abstracts came from Japan, China, South Korea, India and USA, documenting the international interest in this annual event.
The success of this event can be attributed, at least in part, to the efforts of leading members throughout the history of the ESR. In recognition of this fact, the society gave its highest award, a Gold Medal, to Prof. A. Adam (London) for his outstanding contributions to the society and to the field of radiology. Dr. Adam, a professor of interventional radiology, is a founding member of the association and served as its president in 2006-2007. The ESR also awarded honorary society membership to four radiologists who have made important contributions to radiology research and practice: G.J. Becker (Tuscon), W.A. Kalender (Erlangen), J. Qi (Tianjin) and D.L. Resnick (San Diego). Four additional dignitaries were honored by being name as invited lecturers. In particular, A.G. Obsorn (Salt Lake City) gave the opening lecture on brain imaging in AIDS, and additional honorary lectures were given by S.E. Anderson (Sydney) on musculoskeletal imaging, M.N. Brant-Zawadski (Newport Beach) on radiation exposure and cancer, and A.P. Wieczorek (Lublin) on the role of radiology in urinary incontinence.

Abdominal CT at the 2010 European Congress of Radiology

The twenty-second European Congress of Radiology offered its attendees another high-quality program, covering radiological topics in a three hundred sixty degree fashion. CT and, especially, its abdominal applications were central topics of this year's venue, giving participants much food for thought on the way back to their home countries.
During Friday's New Horizons session, Dr. Stolzmann from Zurich gave an interesting lecture on multi-energy CT and its relation to functional imaging. In the coming future, this novel imaging modality may offer new diagnostic possibilities in the abdominal district.
The mini-course entitled “Organs from A–Z: Liver” offered both radiological trainees and experts new insight into the clinical and radiological aspects of this organ. Different lectures, focusing on basic and advanced topics, followed one after the other. The program, divided into four parts, started with an introductory session on anatomy and imaging techniques, including talks on liver anatomy and the multimodality display approach (Dr. Schima, Vienna), CT and MRI protocols, (Dr. Marincek, Zurich), and imaging of liver function and structure (Dr. Menu, Paris). This was then followed by three sessions, each with three lectures, on the assesment of diffuse liver diseases, the description of primary liver tumors, and treatment strategies. In particular, vascular diseases of the liver, their detection and role in transplantation, especially in the context of CT imaging, were addressed in a memorable lecture by Dr. Vilgrain from Clichy.
Scientific sessions also dedicated much attention to abdominal CT, especially regarding new techniques offered by the latest CT technology, i.e. perfusion and dual-energy approaches. Liver perfusion, in particular, permits the evaluation of liver fibrosis in cirrhotic patients (as discussed by Dr. Ronot, Clichy) and the investigation of the response to anti-angiogenic treatment in patients with multifocal liver lesions (as explained by Dr. Menichini, Rome). Dr. Graser (Munich) presented an interesting paper on image quality and radiation exposure offered by second-generation dual-energy CT scanners for abdominal examinations. The quantification of liver fat, compound analysis of gallstones, and quantitative analysis of virtual noncontrast images as a possible means of dose reduction in cirrhotic patients were other hot topics in the field of dual-energy CT imaging of the liver.
Considering the exquisite program that ECR provided its participants this year, it seems truly that 2010 has started with a “radiological virtuosity”.

Dramatic reduction of radiation dose with new cardiac CT scanners: first results presented at ECR 2010

At the 2010 European Congress in Radiology (ECR), radiation dose associated with cardiac CT was again highlighted as an important topic, with a special session on Thursday. Recently, new technological developments such as high-pitch scanning and prospectively triggered acquisition have raised new expectations for the possibility of reducing radiation dose in cardiac CT. Indeed, these two different techniques both permit a significant reduction in the exposure time and, consequently, also in the radiation burden to patients.
The first clinical studies with these new techniques were presented at this year's ECR, confirming the dramatic reduction in radiation dose that had been expected by these technological developments. For example, high-pitch spiral data acquisition with prospective ECG triggering was associated with a radiation dose of only 3 mGy compared to 27 mGy in a comparable low-pitch spiral CT group. This translates to a 9-fold reduction in radiation dose without substantial loss in image quality.
In addition, for the first time, the biological effects of X-rays have been assessed by evaluating DNA double strand breaks (DSB) in lymphocytes. Researchers found a linear relationship between the number of DSB and the dose length product (expressed in mGy*cm). Another presentation described how sub-millisievert acquisition can be achieved using large detector technology with prospectively triggered acquisition and low kilovoltage settings.
On Saturday, a session dedicated to the assessment of atherosclerosis by cardiac CT underlined the potential of this technique to detect non-calcified as well as calcified plaques. The researchers pointed out that the evaluation of coronary arteries with MDCT may be predictive of major adverse cardiac events.
Advanced research in cardiac CT was also the subject of an interesting session on Sunday. The evaluation of cardiac perfusion now appears as feasible with MDCT, especially after correction for beam hardening artefacts. Dual-energy acquisition was also suggested to be a helpful tool for detecting acute and chronic myocardial infarction.
In summary, cardiac CT presentations at ECR were numerous and at a very high scientific level. The newest generation of CT scanners can overcome the main limitations of cardiac CT (i.e. radiation dose) and offers new possibilities for deeper analysis of cardiac structure and function.

Report from the ECR:  Advances in CT neuroimaging

At this year's European Congress of Radiology, session SS 511b, called “Neuro – Advances in CT”, took place on Friday, 5 March 2010 in the Austria Center.  The session reported new trends in CT neuroimaging with a special focus on MDCT.
In the first presentation, D. Morhard from Munich gave a presentation entitled “Stroke CT: CTA or perfusion CT? Which should be done first?” and described a study that had evaluated which order of CT imaging exams is advantageous in a comprehensive stroke work-up. The study underscored the point that contrast medium administration prior to perfusion CT did not have a significant effect on the perfusion parameters. When perfusion CT was performed first, however, there was contrast agent preloading in the veins. Morhard therefore recommended a reversal of the traditional order of exams, with CT angiography being performed first, followed by perfusion CT.
The second presentation by E. Smit from Utrecht was called “Arterial input function characteristics for CT-perfusion in normal patients and patients with carotid stenosis or occlusion".  The background of this study is that the arterial input function (AIF) may result in incorrect regional perfusion measurements, when dispersion or delay occurs due to pathology or a higher distance between the region of the AIF and the measured region. This research group found that TPP and MTT vary between different cerebral arteries especially in patients with unilateral pathology of the internal carotid artery. Smit therefore concluded that a single AIF may not be suitable for regional brain perfusion measurements especially in patients with carotid stenoses.
In the next presentation, L. Saba from Cagliari gave a talk entitled “Carotid artery wall thickness and leukoariosis: Evaluation using multi-detector CT angiography”. This presentation described a study that retrospectively evaluated carotid artery wall thickness (CAWT) in 98 patients and correlated it to the presence and severity of leukoariosis. The researchers found a significant correlation between CAWT and the presence of leukoariosis when a threshold value of 0.9 mm for CAWT was chosen.
In the fourth presentation, D. Maintz from Muenster reported on a study entitled “Evaluation of collateral flow in cerebral vessel occlusion using 4D CT-angiography: impact on the outcome after multi-modal recanalization therapy” (the first author was V. Hesselmann). In this study, researchers evaluated volume-rendered 4D-CT angiography-like datasets from  perfusion CT to assess the degree of collateralization and to correlate it to the patients' outcomes. The group demonstrated that collateral flow could be estimated from the 4D-CT angiography datasets.  In the study population, good collateralization was associated with a significantly better outcome. Maintz, however, mentioned that a limitation of the study was that the patient population was comparatively heterogeneous.
The next paper, “Lower radiation dose adaptive statistical iterative reconstruction head CT examinations match quality of prior conventional dose studies”, was given by L.N. Tanenbaum (first author, E.G. Stein).  In this study, 16 patients were scanned on a Discovery CT750 HD CT scanner and images were reconstructed with adaptive statistical iterative reconstruction. The data were compared to prior CT scans with conventional radiation doses and filtered back projection. The group found the average radiation dose to be significantly reduced by 29% from 1.5 mSv to 1.1 mSv. At the same time, noise levels were comparable and diagnostic image quality was preserved, as assessed by blinded reviewers.
Another presentation was given by F.E. Ebner from Graz on the topic “Digital subtraction volume 4D CT angiography of the brain: reducing radiation dose using a mathematical model for bolus timing”. This study aimed to find an optimal time window for 4D-CT angiography and to limit radiation dose accordingly with 320-row volume CT technology.  Overall, 46 patients were included and received a 10 ml test bolus, followed by a 50 ml regular bolus of contrast medium with an iodine concentration of 370 mg/ml, injected at 6 ml/s. The researchers found the cross-over point between arterial and venous time-density curves to be the most reliable time point to start the regular bolus injection. The radiation dose amounted to 460.8 mGy*cm, which is well below the reference level of 544 mGy*cm for diagnostic head CT.
The subsequent presentation, entitled “Brain perfusion CT using a 256-slice CT: Improvement of diagnostic information by large volume coverage”, was given by F. Dorn from Munich. Her group assessed the feasibility and diagnostic value of CT perfusion with an 8-cm detector. A total of 29 patients with signs of cerebral ischemia were included in the study. The data were compared to those from simulated standard detector CT perfusion at the level of the basal ganglia by two independent readers. Of the 19 lesions identified in this study, 6 would have been missed by standard detector CT perfusion and 10 hypoperfused regions would have only partially been covered.
The last three presentations were given by Z. Jiawen from Shanghai. The first paper,  “ Experimental studies on functional response in normal rat brain to hypercarbia using perfusion CT”, described investigations into changes in CT perfusion values in normal rat brain at hypercarbia and compared these changes to results from immunohistochemical staining. The group found that changes in CBV and CBF correlated well with the number of vessels staining positively for SMA.
The second presentation by Jiawen was called “Experimental studies on functional response of tumoral vasculature to hypercarbia in rat brain C6 glioma model using perfusion CT”. This talk described a study that investigated CT perfusion changes in a rat in vivo glioma model and that found that CT perfusion can reflect angiogenesis in this model. CBV and CBF values under hypercarbia, however, did not correlate well with the number of mature vessels nor with the tumoral vascular maturity index.
Jiawen's third presentation, entitled “Using 64-slice CT perfusion imaging to evaluate the histopathological grade of intracranial gliomas”, described a study that assessed the role of CT perfusion with a 64-slice system in the preoperative grading of cerebral gliomas. The study group included 31 patients with intracranial gliomas who underwent preoperative CT perfusion.  CBV and CBF values correlated well with the grade of the glioma.
In summary, session SS511b provided many insights into the latest advances in neuro-MDCT with a special focus on CT perfusion and 4D-CT angiography.

State-of-the-science conference on colorectal cancer screening

The US National Institutes of Health (NIH), within its consensus development program, recently held a “state-of-the-science” conference on colorectal cancer screening.  These NIH conferences are organized on emerging healthcare topics for which the evidence may be limited or contradictory, with the aims to illustrate the state of knowledge and to set priorities for future research. During these conferences, the results of a systematic review on the subject are presented, researchers discuss their work, independent panelists (without financial or career interests in the matter) present objective views, and a public debate ensues. The result is the production of a “panel statement” that summarizes current knowledge, without determining a specific healthcare policy.
The most recent NIH state-of-the-science conference was entitled “Enhancing Use and Quality of Colorectal Cancer Screening”.  The speakers, predominantly from the US, addressed topics such as trends in the use and quality of colorectal cancer screening, factors influencing the choice to screen, strategies that increase compliance, medical centers' capacity for screening, and monitoring of screening progress and quality. Two presentations specifically addressed CT colonography: one provided data on the ability of US hospitals to offer CT colonography, and another discussed the training and certification of physicians as well as quality control.  Summaries of these and other presentations are available at consensus.nih.gov.
In the final panel statement, the panelists concluded that the extent of colorectal cancer screening in the US is low and that screening does not reach all population subgroups. To improve this situation, they made several recommendations, including the elimination of "financial barriers" to screening, research on how to tailor screening programs to the needs of particular population subgroups, and cost-benefit analysis of different screening methods. The panel statement is available at consensus.nih.gov.

Toshiba explains its dose- and noise-reducing tools

Maintaining radiation exposure as low as reasonably achievable during CT examinations can be achieved by reducing tube current, but this also reduces image resolution due to a concomitant increase in both quantum noise (random pixel fluctuations) and structured noise (artifacts, such as streaking, due to local areas of high attenuation). Noise can be removed from final images by applying smoothing filters, but if not done accurately resolution and texture can be lost. Manufacturers of CT scanners have made major efforts to develop sophisticated algorithms to reduce noise without losing resolution. For users of Aquilion CT scanners, Toshiba has recently published a white paper describing its two noise-reducing, dose-saving tools.
Quantum Denoising Software (QDS) eliminates quantum noise by selectively applying smoothing and sharpening filters to specific parts of an image, resulting in an enhanced image with preserved contrast.  QDS works together with Aquilion's ^SUREExposure mA modulation system, so that tube current is optimized to both the patient's body constitution and the desired image quality. The second tool, called Boost 3D, eliminates quantum as well as structured noise by searching within the raw data set for areas of low photon count.  Together, these two tools permits radiologists to either improve image quality with a fixed radiation dose, or reduce radiation dose with a fixed image quality. 

References

1. Boedeker K. (2010)   Noise reduction tools:  saving dose with QDS and Boost3D. Toshiba America Medical Systems, Tustin, USA
   

Selected literature update
MDCT for gastrointestinal diseases

Researchers from Bari tested the accuracy of 16-slice MDCT with vessel probe (VP) reconstruction in the preoperative T staging of gastric carcinoma [ 1]. VP software permits reconstruction of gastric wall layers through 3D visualization of arterial vessels during contrast-enhanced imaging. Their study enrolled 53 patients with a diagnosis of gastric adenocarcinoma who underwent MDCT prior to partial or total gastrectomy. Compared to the histological diagnosis made on resected specimens, MDCT with VP reconstruction detected 98% of all lesions (missing one early cancer) and accurately determined T stage in 94% of cases. In contrast, without VP analysis, 90% of lesions were identified but accurately staged in 68%. The authors suggested that incorporation of VP reconstruction in the MDCT workup of these patients is a fast and easy way to improve accuracy.
Pediatric Crohn's disease was the focus of a review offered by researchers working in Ann Arbor (Michigan) [ 2]. Radiological evaluation of Crohn's disease is possible by numerous methods, including CT enterography which reveals both intestinal and extraintestinal manifestations of the disease. The paper describes the CT enterography examination, especially regarding contrast medium administration, image acquisition and radiation exposure control. It then illustrates, with numerous cases, the wide range of CT enterography findings, including bowel and mesentery involvement, penetrating disease, intra-abdominal fluid, bone and urinary tract disease, and finally cholelithiasis.

References

1. Moschetta M., Stabile Ianora AA, Anglani A. et al. (2010)     Preoperative T staging of gastric carcinoma obtained by MDCT vessel probe reconstructions and correlations with histological findings . Eur Radiol 20(1):138-145
   
2. Dillman JR, Adler J., Zimmermann EM, Strouse PJ (2010)     CT enterography of pediatric Crohn disease . Pediatr Radiol 40(1):97-105
   

A catchy rule to guide decisions about CT for minor head trauma in children

Minor pediatric head trauma is a common occurrence that rarely requires neurosurgical intervention. Still, given the fear of intracranial hematoma, emergency physicians often request a CT examination, despite concerns about costs and radiation exposure. Recognizing the need for evidence-based guidelines to support decision-making in this difficult situation, a head injury study group was formed within Pediatric Emergency Research Canada.
The group organized a prospective, 10-center study [ 1 ] to collect clinical and outcome data on children (<17 years of age) who presented with blunt head trauma causing loss of consciousness, amnesia, disorientation or other symptoms and who had a Glasgow Coma Score ≥13. Children underwent a standardized clinical and neurological examination, and CT was performed at the physician's discretion. Clinically important brain injury was defined from CT findings;  in cases in which CT was not done immediately, children were followed up at 14 days and were classified as not having brain injury unless there were signs or symptoms necessitating recall for CT. Univariate analysis was used to identify variables associated with the primary outcome (neurological intervention), and then recursive partitioning was done to find a combination of variables that was both sensitive and specific in predicting this outcome.
Over more than 4 years, the study enrolled 3866 patients of which 24 (0.6%) had neurosurgery. CT was performed in 2043 children (52.8%) and brain injury was diagnosed in 159 cases (4.1%). Recursive partitioning analysis identified seven criteria predictive of brain injury, including four that defined patients at high risk: Glasgow Coma Score <15 two hours after injury, evidence of open or depressed skull fracture, worsening headache and irritability. These four criteria had 100% sensitivity and 70.2% specificity, and implied that about 30% of children with minor head trauma should have a CT examination. The clinical decision rule based on all seven criteria, termed Canadian Assessment of Tomography for Childhood Head Injury (CATCH), is expected to help standardize – and minimize – the use of CT for minor pediatric head trauma.

References

1. Osmond MH, Klassen TP, Wells GA et al. (2010)   CATCH: a clinical decision rule for the use of computed tomography in children with minor head injury. CMAJ Feb 8. [Epub ahead of print]
   

Learn cardiac CT in Berlin

Hands-on experience in state-of-the-art cardiac CT can be acquired by attending one of the twice-yearly workshops organized by Marc Dewey and colleagues, from the cardiac imaging group of the Department of Radiology, Charité Medical University.   In two half-day sessions, up to 20 participants attend lectures and practical demonstrations and are guided in the use of image processing software.  Lectures address patient preparation, scanning, image reconstruction and analysis, and cardiac anatomy.  Clinical CT examinations are demonstrated using Sensation 64 (Siemens) and Aquilion ONE and Aquilion 64 (Toshiba) scanners. Then, participants spend up to 3 hours on Vitrea workstations learning to analyze CT angiographic images.
This year, the workshops will be held in English in April and September 2010 and in German in June 2010, on the Charité Campus Mitte, in Berlin.  A substantially discounted fee is offered to medical residents.  The program has been awarded 20 CME credits by the Berlin Medical Council. A program and registration information are available at s196588120.e-shop.info.

Selected literature update
MDCT coronary angiography protocols for radiation dose reduction:  a review and a comparative study

To combat the mounting radiation exposure that has accompanied the technological advances in MDCT, which now permits accurate, noninvasive examination of the coronary arteries, several dose-reducing scanning protocols have been developed. Two papers selected for inclusion in MDCT.net's full text literature archive offer analyses of the feasibility, indications and effectiveness of scanning protocols that limit radiation exposure during MDCT coronary angiography.
Horiguchi and colleagues from Japan compared retrospective ECG-gated spiral CT to the newer prospective ECG-triggered sequential CT [ 1]. This review, published in Current Cardiovascular Imaging Reports, provides a detailed description of the two acquisition protocols, examines the radiation exposure of these two methods compared to other imaging protocols, and summarizes current knowledge on the clinical indications and diagnostic performance of the prospective ECG-triggered technique which, the authors concluded, permits a substantial radiation reduction in patients with low, stable cardiac rhythms.
Malagò and coworkers in Verona, Italy, clinically tested two dose-saving protocols compared to standard 64-slice CT angiography and published their results in La Radiologia Medica [ 2 ]. In the study, the researchers followed an empirical scheme (based on body mass index and heart rhythm) to select patients for the standard method or for one of two dose-saving protocols, namely “cardiac dose right” and “step and shoot”. Overall, 14 patients underwent standard CT angiography (constant tube current with retrospective ECG gating), 45 patients had cardiac dose right CT angiography (ECG-modulated current with retrospective ECG gating), and 6 patients had step and shoot CT angiography (prospective ECG triggering of tube current). Image quality was apparently comparable in all three groups (although a statistical analysis was not done, possibly because of the different group sizes). Effective dose was 20.5 mSv in the standard protocol group, 14.8 mSv in the cardiac dose right group, and 6.6 mSv in the step and shoot group. The authors concluded that these dose-reducing protocols, when applied to accurately selected patients, reduce radiation dose by 30% and 70%, respectively.

References

1. Horiguchi J., Yamamoto H., Kihara Y., Ito K. (2009)    Prospective ECG-triggered sequential versus retrospective ECG-gated spiral CT: Pros and cons . Curr Cardiovasc Imaging Rep 2(6):447-454
   
2. Malagò R., D'Onofrio M., Baglio I. et al. (2009)     Choice strategy of different dose-saving protocols in 64-slice MDCT coronary angiography . Radiol Med 114(8):1196-1213.
   

Focus on MDCT of the thorax

The first issue of 2010 of the bimonthly Radiological Clinics of North America is dedicated to MDCT applications in the thorax. Edited by S. Bhalla of the Washington University School of Medicine (St. Louis, USA), the issue offers 12 chapters on a range of thoracic imaging topics, authored by radiologists from the USA, Korea and France. Overall, the issue summarizes the advances of thoracic MDCT in the past decade, achieved both through improving existing clinical protocols and permitting the development of new ones [ 1]. Individual chapters discuss the history of chest CT, contrast optimization, and clinical imaging applications such pulmonary embolism, acute aortic syndrome, congenital vascular defects, lung nodules, airways, chest pain. A final chapter discusses thoracic applications of dual-energy CT.
MDCT is frequently addressed in this journal's thematic issues. The upcoming March 2010 issue will be dedicated to CT angiography

References

1. Bhalla S. (2010)   Thoracic multidetector CT comes of age. Preface. Radiol Clin North Am 48(1):xiii-xiv
   

Standardization of CT contrast procedures for improved safety

The safe and effective use of iodinated contrast medium requires an accurate assessment of patients' clinical risks, a correct choice of protocols, and a rigorous handling of information regarding contrast reactions. Managing the clinical and imaging data pertinent to contrast medium use can be challenging, especially in radiology departments that serve large numbers of outpatients. This is even more difficult within a healthcare system that comprises multiple hospitals.
Kahlon and colleagues at Partners Healthcare System, a nonprofit organization based in Boston, realized that across their six member hospitals each CT unit used different approaches to assess risks for adverse events, different protocols to administer contrast medium, and different criteria to define contrast medium reactions. Moreover, data on contrast reactions were not archived in electronic clinical records, hindering physicians' access to important information prior to prescribing or performing successive CT examinations. Therefore, a “CT contrast team” was established to assess current procedures, to identify critical areas in the workflow process, and to develop standardized procedures for all hospitals in the group. The team adopted the American College of Radiology's classification of contrast reactions, developed a standard patient questionnaire, established a single contrast medium administration policy, and produced an adverse event form. The electronic medical record (EMR) software was also updated to permit the recording of contrast medium information directly into patients' clinical records.
Now that the new materials and protocols have been implemented, radiologists, technologists and nurses have ready access to each patient's contrast history and can record new adverse events directly in the EMR system. These standardized procedures and information management strategies now also permit this healthcare system to monitor its CT safety performance. According to the authors, this single positive experience can be widely adopted by other large radiology departments

References

1. Kahlon P., McCulllough K., Gazelle GS (2009)    Enhancing patient safety: standardization of CT contrast media practices. J Am Coll Radiol 6:562-566
   

Innovative color CT scanner with European particle detection technology

Researchers from New Zealand have developed an almost space-age color CT scanner called MARS (Medipix all resolution system). The MARS scanner carries a Medipix X-ray detector chip that counts photons and classifies them by energy level, thereby permitting spectroscopic (or spectral) imaging and the creation of color images. The detector chip, developed in a collaboration between the European Organization for Nuclear Research (CERN) and 18 research groups worldwide, is based on CERN particle detector technology used for high-energy physics. Prototype MARS scanners are now available in North American laboratories for clinical testing.
Preliminary results with the MARS scanner, tested on phantoms and small animals, were presented at this year's annual meeting of the Radiological Society of North America (A.P.H. Butler et al., conference presentation code SSC16-01). The “multi-energy” scanner was shown to distinguish contrast agents of different compositions (e.g. iodine, barium, gadolinium). The scanner can also apparently distinguish contrast agents from diverse biological tissues. The researchers predict that this innovative color CT scanner will improve diagnostic imaging, facilitate the development of new applications, and make CT scanning faster and safer. More information about the MARS-CT project is available at wiki.canterbury.ac.nz.

Selected literature update
Seminal 2006 MDCT book now available in updated forms

The book MDCT: A Practical Approach, edited by distinguished radiologists Saini, Rubin and Kalra and published by Springer in 2006, was reissued in 2008 in a revised and expanded version. The original volume was organized in five sections, beginning with “Physics and techniques of MDCT” and then progressing through the major areas of clinical application: abdomen, cardiovascular system, head and neck, and trauma.
The new volume, called MDCT: From Protocols to Practice, has the same editors and maintains the same structure. However, the original chapters have been updated, several sections have been expanded with new chapters, and a small section on pediatric MDCT has been added. The new volume, like its predecessor, ends with an appendix reporting state-of-the-art imaging protocols.

New U.S. FDA recommendations for avoiding accidental radiation overdose during MDCT perfusion examinations

In early December 2009, the US Food and Drug Administration (FDA) issued interim practice recommendations for MDCT facilities performing perfusion imaging [ 1]. The initiative was prompted by the notification of over 250 cases of radiation overdose during brain perfusion examinations. According to a safety alert released in October 2009 [ 2 ], 206 patients at one Californian hospital received about 8-times the normal radiation dose (maximum, 0.5 Gy to the head). The error came to the attention of physicians when patients complained of alopecia and erythema. Through FDA investigations, an additional 50 cases have been identified in California, and other states have reported possible cases of radiation overdose.
The medical error does not seem to be linked to the scanner, as patients had been imaged with instruments produced by two manufacturers. Although the exact cause is currently unknown, one may surmise from the FDA recommendations and from reporting in the general press that the error was operator-dependent, due to the use of incorrect scanner settings.
The FDA recommendations, which apply to all CT perfusion studies, emphasize quality assurance. In particular, the FDA recommends that CT facilities review imaging protocols to check that the radiation doses are correct and that they implement quality control procedures to guarantee that protocols are followed. Moreover, technologists are cautioned to check scanner settings before each study, while manufacturers are encouraged to improve user training.

References

1. FDA (2009)   FDA makes interim recommendations to address concern of excess radiation exposure during CT perfusion imaging. US Food and Drug Administration, Washington, 7 December 2009
   
2. FDA (2009)   Safety investigation of CT brain perfusion scans: initial notification. US Food and Drug Administration, Washington, 8 October 2009
   

CT expert honored as the 2009 RSNA Outstanding Educator

The presentation of two prestigious radiology awards marked the opening of the 95th annual meeting of the Radiological Society of North America (RSNA), recently held in Chicago. During the opening session, the RSNA honored two senior radiologists who have made significant contributions throughout their careers in the fields of radiological education and research.
The 2009 RNSA Outstanding Researcher award was given to Sanjiv Sam Gambhir, professor of radiology and bioengineering at Stanford University. Dr. Gambhir is a world leader in molecular imaging, especially for his development of a Raman nanomolecular imaging approach.
The recipient of the RSNA Outstanding Educator award this year was Dr. Elliot K. Fishman, professor of radiology at Johns Hopkins University and director of diagnostic imaging and body CT at the Johns Hopkins Hospital. Also at Johns Hopkins, Fishman heads the Advanced Medical Imaging Laboratory (AMIL), which aims to improve patient care through research and educational activities, especially regarding spiral CT and 3D imaging technologies. Of the over 800 papers in Medline authored by Dr. Fishman, more than two dozen address the training of radiologists, especially regarding the use of web-based tools.

MDCT scoring systems for interstitial lung diseases: possible use in primary graft dysfunction in lung transplant recipients

The high resolution of 64-slice MDCT has permitted the development of semiquantitative scales for grading the severity of lung pathologies. Most work thus far has focused on the grading of cystic fibrosis, adult respiratory distress syndrome and idiopathic pulmonary fibrosis. There is presently no CT-based scoring system for primary graft dysfunction (PGD), a common early complication of lung transplantation that adversely affects graft success and long-term clinical outcomes. A diagnosis of PGD is currently based on the results of plain radiography and lung function tests. A sensitive imaging test to grade and localize PGD could positively impact the care of lung transplant recipients.
Recognizing the need for a PGD scoring system, researchers at Copenhagen University Hospital systematically reviewed existing CT-based scales for interstitial lung diseases. Their paper, published in Interactive Cardiovascular and Thoracic Surgery [ 1], summarized each scale's parameters and reported values of sensitivity, inter- and intraobserver variability, and reproducibility. From this analysis, they devised a 9-parameter MDCT scoring system for PGD, to be applied to each pulmonary lobe in central and peripheral zones; four additional CT findings outside the lung are also scored. The new scale will be tested clinically in 70 consecutive lung transplant recipients at Rigshospitalets in Copenhagen.






References

1. Belmaati E, Jensen C., Kofoed KF et al. (2009)   Primary graft dysfunction; possible evaluation by high resolution computed tomography, and suggestions for a scoring system. Interact Cardiovasc Thorac Surg 9:859-867
   

Selected literature update
Diagnostic performance of MDCT for gastrointestinal diseases

Two papers selected in October for MDCT.net's literature database examined the performance of MDCT in diagnosing gastrointestinal (GI) pathology. Both papers were contributed by researchers from Sapienza University in Rome.
Frattaroli and colleagues [ 1] examined the use of MDCT in determining the site and etiology of acute GI bleeding in 29 patients with suspected bleeding. Patients underwent both contrast-enhanced 16-slice MDCT and endoscopy (upper endoscopy or colonoscopy, depending on clinical signs). For MDCT, bleeding was defined as extravasation of contrast material into the GI tract. Sensitivity was calculated by accepting as true diagnosis either: (i) the diagnosis made during surgery or autopsy, or (ii) the diagnoses given by the two investigated methods when they were in agreement. In 11 patients with upper GI disease, MDCT had a sensitivity of 100% and 90.9%, respectively, in identifying the site and etiology of the bleeding. In 17 cases with lower GI disease, these values were 100% and 88.2%. Based on these encouraging results, the authors proposed a diagnostic protocol in which these patients first undergo MDCT and then, only if findings are negative despite persistent bleeding, also endoscopy.
Anzidei and coworkers [ 2 ] compared the diagnostic performance of contrast-enhanced 64-slice MDCT and 1.5 T MRI in 40 patients with an endoscopic diagnosis of gastric cancer, using as final diagnosis the results from histopathological analysis of surgical specimens. The study confirmed the high accuracy and sensitivity of MDCT (both 89.4%) in the local staging of advanced tumors (T3 and T4) and demonstrated that MRI has an equivalent diagnostic performance.






References

1. Frattaroli F., Casciani E., Spoletini D. et al. (2009)  Prospective study comparing multi-detector row ct and endoscopy in acute gastrointestinal bleeding. World J Surg 33(10):2209-2217
   
2. Anzidei M., Napoli A., Zaccagna F. et al. (2009)   Diagnostic performance of 64-MDCT and 1.5-T MRI with highresolution sequences in the T staging of gastric cancer: a comparative analysis with histopathology. Radiol Med 114(7):1065-1079
   

ACR position statement: CT colonography is ready for community practice

Last month, the American College of Radiology (ACR) issued revised practice guidelines on the use of CT colonography in adults [ 1]. This was accompanied by a position statement [ 2 ] from the ACR Colon Cancer Committee, author of the guidelines, in which state-of-the-art knowledge on CT colonography was reviewed and the scientific rationale for the guidelines was explained.
Briefly, based on current evidence, the ACR Colon Cancer Committee has determined that CT colonography – when performed according to the latest technical standards – is equivalent to optical colonoscopy in detecting advanced neoplasia. Given continuing technological improvements in CT, the diagnostic performance of this examination is expected to improve further. Based on its safety profile, the authors considered this diagnostic method as both an “effective adjunct to colonoscopy” and a “frontline option” for screening adults with average risk for colorectal cancer, starting at age 50 years. Persons in whom polyps ≥6 mm are found should have colonoscopy and polypectomy, and may benefit from surveillance with CT colonography.
The ACR's position is that CT colonography is now ready for routine use in the community. Critical issues for its effective implementation outside of the controlled research environment include the training of radiologists and the development of reliable quality control measures. Inclusion of CT colonography in public and private healthcare plans will depend on the demonstration of cost-effectiveness in different national settings together with a better understanding of the health risks from radiation exposure during the examination.

References

1. ACR Colon Cancer Committee (2009)   ACR practice guideline for the performance of computed tomography (CT) colonography in adults, revised 2009 (resolution 36). American College of Radiology, Reston
   
2. McFarland EG, Fletcher JG, Pickhardt P. et al. (2009)  ACR Colon Cancer Committee white paper: status of CT colonography 2009. J Am Coll Radiol 6:756-772
   

CT technologies rank high among 2009 Minnies awards

CT technologies and applications placed well in the 2009 Minnies awards for radiological excellence. In particular, coronary CT angiography was considered the hottest clinical procedure, and Siemens Healthcare's Somatom Definition Flash CT scanner was deemed the best new radiological device (with Toshiba's Aquilion Premium CT scanner in second place). A report on 64-slice CT angiography in patients with chest pain (Fazel et al., Am J Cardiol) took second place in the best scientific paper category. CT was also behind the best new radiological software, with Vitrea Enterprise Suite (Vital Images) and ASIR dose reduction software (GE Healthcare) in first and second places, respectively.
The Minnies is a series of awards for radiological excellence given by Auntminnie.com, an online community for radiologists and medical imaging professionals. Candidates for the Minnies are nominated by the website's registered visitors, while winners are chosen by an expert panel. Awards are given in 13 categories that recognize influential persons, new technologies, current radiological issues, leading institutes, the hottest clinical procedure and the best scientific paper of the year. This year's Minnies winners were announced at the end of October.

320-slice MDCT for coronary stent analysis: ongoing trial

Patients with coronary artery stents require follow-up angiography so that the long-term outcomes of the procedure can be assessed and that re-stenosis and disease progression in other coronary segments can be monitored. Despite the great interest in developing a noninvasive imaging method to assess coronary stents, a meta-analysis published in 2008 concluded that 16- to 64-slice MDCT angiography was insufficiently sensitive (82%) for this clinical indication ( see MDCT.net news of August 2008 ) [ 1 ]. Recent studies using 64-slice MDCT have achieved greater sensitivity values, but problems due to blooming and motion artifacts remain [ 2 ].
Researchers at Charité University in Berlin, Germany, led by Dr. Marc Dewey, are undertaking a prospective clinical study to determine if 320-slice MDCT angiography has sufficient diagnostic accuracy to be used in the evaluation of coronary artery stents. The Coronary Artery Stent Evaluation with 320-slice Computed Tomography (CARS 320) study began in April 2009 and is currently recruiting 90 patients aged 40 years or older who require conventional coronary angiography for suspected in-stent restenosis. The trial has been registered at the US National Institutes of Health's clinical trial registry (clinicaltrials.gov).







References

1. Vanhoenacker PK, Decramer I., Bladt O. et al. (2008)  ultidetector computed tomography angiography for assessment of in-stent restenosis: meta-analysis of diagnostic performance. BMC Med Imaging 8:14
   
2. Nieman K. (2009)  Noninvasive stent imaging with MSCT. Eurointervention 5[Suppl D]:D107-111
   

Profile: European Society of Paediatric Radiology

Within Europe and the Mediterranean area, the professional meeting point for pediatric radiologists is the European Society of Paediatric Radiology (ESPR, www.espr.org). This association aims to promote excellence in pediatric imaging by offering opportunities for continued learning in clinical and scientific areas.
The ESPR organizes an annual meeting and postgraduate course which, in 2009, was held in Istanbul; next year's meeting will be in Bordeaux.  At these meetings, ESPR acknowledges its leading members with a series of awards, including a gold medal for life-long service to the field as well as several research awards. ESPR also hold an annual course in pediatric radiology: this year's course in Amsterdam was devoted to gastrointestinal and urogenital imaging, while next year's course in Florence will focus on heart and chest imaging. The ESPR and the US-based Society of Pediatric Radiology hold a joint international meeting every 5 years;  the next such meeting is planned for 2011 in the UK.  These two societies, plus similar associations from Asia and Latin America, work with Springer to produce the journal Pediatric Radiology (see also MDCT.net selected literature archive).

Selected literature update
LV function analysis in patients with mitral valve regurgitation: value of 64-slice MDCT

In primary mitral regurgitation, valvular abnormalities cause the valve to leak, leading to stress on the left ventricle (LV) that may result in permanent damage. Accurate assessment of LV function is essential to determine a patient's prognosis and to guide decision-making about surgery to repair or replace the value. LV function has typically been studied with echocardiography, although the reference method today is cardiac MRI. Early studies using 4- and 16-slice MDCT did not achieve a satisfactory level of accuracy for this purpose. Therefore, researchers from Sichuan University in China tested the possibility of using 64-slice MDCT to evaluate LV function in patients with mitral regurgitation.
In the study, 51 consecutive patients with mitral regurgitation, often with other heart conditions, underwent trans-thoracic echocardiography (2DTTE) and, a few days later, both 64-slice MDCT and MRI.  MDCT was performed with retrospective ECG gating and contrast enhancement, during a single breath hold.   Myocardial mass and LV function parameters were calculated and compared between MRI and the two other diagnostic methods.   In particular, MRI and MDCT gave similar values of end-diastolic and end-systolic volumes, stroke volume, ejection fraction and myocardial mass, with a high intrapatient correlation between the two techniques (Pearson's r, 0.89-0.96).  The authors concluded that 64-MDCT can be used to accurately assess LV function and is especially useful in those patients with limited breath-holding ability or in whom MRI is contraindicated (see also MDCT.net selected literature archive).

References

1. Guo YK, Yang ZG, Ning G. et al. (2009)   Sixty-four-slice multidetector computed tomography for preoperative evaluation of left ventricular function and mass in patients with mitral regurgitation: comparison with magnetic resonance imaging and echocardiography . Eur Radiol 19(9):2107-2116
   

MDCT for measuring aortic valve area: meta-analysis

Stenosis of the aortic valve is a degenerative condition often associated with coronary artery disease. The severity of this condition is typically assessed from the aortic valve area measured using transesophageal echocardiography (TEE) or cardiac catheterization, although recently several studies have described the use of electrocardiography-gated MDCT for this purpose. Researchers from the Cleveland Clinic Florida did a meta-analysis to determine the diagnostic accuracy of MDCT for aortic valve area measurements [ 1 ].
The meta-analysis included 9 studies that assessed aortic valve area using 16-slice or higher MDCT and also TEE as the reference standard. Altogether, the studies included 437 patients, most of whom had known aortic stenosis. These patients had aortic valve areas that ranged from 0.1 to 2.0 cm2 (normal value, about 3 cm2) irrespective of the diagnostic technique. The mean value obtained with MDCT was 1.0 cm2 while that with TEE was 0.9 cm2. There was a strong correlation in the intra-individual results between the two methods (Pearson's r=0.89). The authors concluded that MDCT is “feasible and reasonably accurate” for measuring aortic stenosis and therefore recommended it as a supplementary method, especially when TEE is not diagnostic.

References

1. Shah RG, Novaro GM, Blandon RJ et al. (2009) Aortic valve area: meta-analysis of diagnostic performance of multi-detector computed tomography for aortic valve area measurements as compared to transthoracic echocardiography . Int J Cardiovasc Imaging 25(6):601-609

Selected literature update
MDCT for abdominal emergencies

Two retrospective studies published in August 2009 and selected for inclusion in MDCT.net's literature archive addressed the use of abdominal 4- or 16-slice MDCT in emergency situations.
Researchers from Bari assessed the prognostic value of contrast-enhanced MDCT in 27 patients with bowel infarction due to arterial or venous occlusive ischemia [ 1 ]. Mortality was significantly higher among patients with arterial infarctions (88% vs. 11%). MDCT permitted a correct diagnosis of the arterial or venous nature of the infarction in all cases. Moreover, specific CT findings were associated with prognosis, e.g. pneumoperitoneum and intramural pneumatosis were predictive of a fatal outcome whereas wall thickening was more commonly seen in patients with good outcomes. The authors recommended MDCT for all patients with acute abdomen due to its high diagnostic and prognostic value.
Researchers from Baltimore studied the diagnostic accuracy of triple-contrast-enhanced MDCT in 136 patients with a suspicion of penetrating trauma to the diaphragm [ 2 ]. MDCT was performed at admission to a trauma center, and diaphragmatic injury was confirmed during surgery in 47 cases. Blinded radiologists evaluated CT images for six signs; they accurately identified diaphragmatic injury in 41 patients (sensitivity, 87%) and excluded such injury in 71 cases (specificity, 72%). Considering individual CT findings, the sign of contiguous injury on either side of the diaphragm had the best diagnostic accuracy.







References

1. Moschetta M., Stabile Ianora AA, Pedote P. et al (2009) Whole-lung densitometry versus visual assessment of emphysema. Radiol Med 114(5):780-791
   
2. Bodanapally UK, Shanmuganathan K., Mirvis SE et al. (2009)  MDCT diagnosis of penetrating diaphragm injury. Eur Radiol 19(8):1875-1881.
   

Anticipating ECR 2010

The next European Congress of Radiology (ECR) will be held in Vienna on 4-8 March 2010. It will be presided by Dr. Małgorzata Szczerbo-Trojanowska (Lublin, Poland), who discussed the key topics of ECR 2010 earlier this year in an interview with ECR Today [ 1 ].
According to Szczerbo-Trojanowska, the thematic focus of ECR 2010 will be on imaging in oncology and in clinical emergencies. The coming meeting will introduce a new type of session, called “Organs from A to Z”, which will debut by focusing on the liver. Another innovation is the introduction of multidisciplinary symposia designed to help radiologists update their clinical knowledge; at ECR 2010, there will be four such sessions in which pulmonary, colorectal, prostatic and uterine-cervical cancer are each discussed from the viewpoints of a surgeon, an oncologist and a radiologist. Several sessions will address state-of-the-art applications of computed tomography, such as functional CT, cardiothoracic CT, volumetric CT and CT colonography.
The programming committee is still accepting abstracts for presentations and posters (deadline, 18 September). Online registration is now possible, and the discounted fee for early registration is available until 10 November. The preliminary program, replete with interviews and special topic articles, is now online: www.myesr.org.

References

1. Rouger M. (2009) ECR 2010 President urges radiologists to contribute to further development of specialty. ECR Today, 9-10 March 2009.
   

Profile: Royal Belgian Radiological Society

Founded in 1906, the Royal Belgian Radiological Society has three main objectives: to promote basic and clinical research in radiology, to disseminate scientific knowledge about radiology, and to support the education of its members. The association is currently presided by Dr. G. Villiers and is structurally organized into nine thematic sections. Each year, the association holds an annual symposium and several meetings organized by the individual sections. This year's symposium is dedicated to genitourinary radiology and will be held in Ghent in November; an honorary lecture on emergency imaging in pregnant women will be given by S. Goldman of Houston.
The society publishes a bimonthly journal JBR-BTR (formerly, the Journal Belge de Radiologie - Belgisch Tijdschrift voor Radiologie), in English, French and Dutch languages. The journal is indexed in Medline and freely available in full text since 2001 through the society's website www.rbrs.org.

Acute chest pain: towards development of a diagnostic and prognostic algorithm

Acute chest pain requires a rapid and reliable diagnosis to determine if a patient is at risk for myocardial ischemia or infarction. For this purpose, there are numerous tests based on specific signs and symptoms, laboratory determinations and diagnostic images, although the best combination of these methods is unknown. Researchers at the University Medical Center of Groningen, The Netherlands, are conducting a 3-year prospective study to evaluate a diagnostic algorithm for the quick identification of high-risk patients among those who present with acute chest pain [ 1 ].
The algorithm begins with a clinical workup, including electrocardiography and 21 standard laboratory tests, which permits classification of patients into 4 groups: myocardial infarction, chest pain with high probability of acute coronary syndrome (ACS), chest pain with low ACS probability, and non-cardiac chest pain. Patients with infarction are treated in hospital, while those with chest pain of a presumed cardiac origin undergo electron beam tomography and, in case of high calcium score, also 64-slice contrast-enhanced CT angiography. Blood samples are taken for determination of ACS biomarkers.
The primary objective of the study is to determine if myocardial ischemia or a future cardiac event can be ruled out based on the calcium score, biomarker profile or imaging findings; the secondary objective is to identify the combination of clinical signs and symptoms, biomarkers and imaging findings that best predicts the prognosis of patients with acute chest pain. The methods and rationale for the study have been reported [ 1 ]; the first results are expected later this year.

References

1. Willemsen HM, de Jong G., Tio RA et al. (2009) Quick identification of acute chest pain patients study (QICS) . JAMA 301(5):500-507

MDCT for assessment of respiratory pathology

Among articles selected this month for inclusion in MDCT.net's literature archive are two reports of studies that compared MDCT to standard methods for assessing respiratory pathology.
Italian researchers focused on quantifying the fibrotic damage from chronic obstructive pulmonary disease in 30 patients [ 1 ]. They prospectively compared automated whole-lung densitometry to visual assessment of 16-row MDCT images, elaborated according to two different post-processing algorithms. In particular, densitometry was done on 5-mm slices taken at 5-mm increments over the entire lung and reconstructed with a smooth filter; visual assessment used a 1-mm thickness but considered one of every ten slices taken at 1-mm increments and reconstructed with a sharp filter. Automated densitometry took longer but was more reproducible than visual assessment. Both methods correlated moderately but significantly with a respiratory function test. The authors recommended the automated method for its greater reproducibility.
Researchers from South Africa studied airway compression due to tuberculosis in 26 children aged 4-84 months [ 2 ]. They retrospectively assessed the ability to identify and grade sites of compression using 4-slice contrast-enhanced MDCT with three-dimensional visual rendering. MDCT permitted the identification of almost 60% more sites than did flexible bronchoscopy, the reference method. For sites identified by both tests, agreement on the degree of narrowing was moderate (k=0.39). Compared to bronchoscopy, MDCT had a 92% sensitivity and an 85% specificity for identifying airway compression. The authors concluded that MDCT is complementary to bronchoscopy in evaluating airway obstruction in children.







References

1. Cavigli E., Camiciottoli G., Diciotti S. et al. (2009) Whole-lung densitometry versus visual assessment of emphysema. Eur Radiol 19(7):1686-1692
   
2. du Plessis J., Goussard P., Andronikou S. et al. (2009) Comparing three-dimensional volume-rendered CT images with fibreoptic tracheobronchoscopy in the evaluation of airway compression caused by tuberculous lymphadenopathy in children. Pediatr Radiol 39(7):694-702
   

Diagnostic imaging and pregnancy: revised UK guidelines

The UK Health Protection Agency, together with the Royal College of Radiologists and the College of Radiographers, has recently updated its 1998 guidelines on the use of diagnostic imaging involving ionizing radiation in women of childbearing age. The 24-page document, entitled “ Protection of Pregnant Patients during Diagnostic Medical Exposures to Ionising Radiation” [ 1 ], is targeted to hospital physicians working in radiology and nuclear medicine.
The first part of the report summarizes scientific evidence on the fetal health effects of in utero exposure to radiation. During normal imaging procedures, an embryo or fetus is unlikely to suffer direct tissue damage resulting in death or malformation (deterministic effects), as long as the exposure remains below a 100 mGy threshold. Low levels of radiation, however, may cause gene mutations leading to childhood cancer or hereditary diseases. For these stochastic effects, there is no recognized safety threshold and the risk is directly associated with the radiation dose. To illustrate this fact for childhood cancer, the authors grouped common diagnostic imaging procedures that pregnant women may undergo into 5 categories ranging from low-exposure examinations with low fetal risk (e.g. dental X-ray and mammography) to high-exposure examinations with high fetal risk (e.g. pelvic CT and whole body 18F-PET-CT). Examinations in the higher exposure categories may double the risk of childhood cancer and thus should be avoided whenever possible. Compared to the risk of cancer, the risk of heritable effects from an in utero exposure to radiation was so low as to be considered negligible.
The second part of the document offers guidance on the safe use of diagnostic imaging in pregnant women and in women who could have an as yet unrecognized pregnancy. The report also briefly addresses the medical-professional issues raised when a fetus is inadvertently exposed to radiation.

References

1. HPA, RCR, CoR (2009)  Protection of pregnant patients during diagnostic medical exposures to ionising radiation. Doc HPA RCE-9
   

Head and neck radiology: a conference and course in Verona

The European Society of Head and Neck Radiology (ESHNR) will hold is twenty-second annual meeting and refresher course on 1-3 October 2009 at Palazzo della Gran Guardia, in Verona, Italy. The meeting has been organized by Dr. Roberto Maroldi (Brescia) together with an international scientific committee and with the support of the European Society of Neuroradiology and six Italian medical associations.
The three-day program will address the pathology, treatment and imaging of head and neck diseases, including lymph node metastases, nose and sinus tumors, squamous cell carcinoma of larynx, inner ear disease, temporomandibular joint and facial pain, bone tumors, salivary and orbital lesions, neurogenic tumors, and trauma. The afternoon of the third day will be dedicated to a refresher course on head and neck anatomy and pathology. Almost 50 speakers from all of Europe and Australia have been invited to give the plenary and parallel sessions. A full program and registration information are available at www.eshnr2009.org.

Radiation dose reduction in cardiac CT angiography: impact of a best-practice imaging program

Cardiac CT angiography can expose a patient to a substantial amount of radiation but, as revealed by the PROTECTION I study [ 1 ], the actual dose varies widely and depends on the choice of scanning parameters and on each patient's characteristics. Dose-reduction techniques are available but are not used consistently, possibly for lack of awareness or for concerns about image quality.
The Advanced Cardiovascular Imaging Consortium, comprising imaging centers in Michigan, devised a best-practice program to train radiologists in dose-reduction techniques and investigated the impact of this program on patients' radiation exposures [ 2]. The year-long study had three phases: (i) a 2-month run-in period in which scanning practices and radiation doses were monitored, (ii) an 8-month intervention period in which participants were trained to apply an evidence-based best-practice model for CT angiography acquisition, and (iii) a 2-month follow-up period. Overall, 15 centers participated and data from 4862 patients were analyzed, including 620 during the run-in and 835 in the follow-up.
In the run-in period, median dose-length product was 1493 mGy · cm (interquartile range (IQR), 855-1823) and effective dose was 21 mSv (IQR,12-26). During the training program these values fell by more than 50%, to 697 mGy · cm (IQR, 407-1163) and 10 mSv (IQR, 6-16), respectively, in the follow-up period (p<0.001). The rate of diagnostic-quality exams increased slightly (from 89% to 92%, p=0.07) while the median scan quality score remained the same. The most important factor in reducing radiation dose was use of low tube voltage (100 kVp) in patients ≤85 kg with a body mass index <30 kg/m ².
This prospective study confirmed that patients who undergo cardiac CT angiography are exposed to a high but variable radiation dose and that this exposure can be modulated by an accurate choice of scanning parameters. The study also demonstrated that an evidence-based best-practice algorithm for choosing scan parameters is effective and that a collaborative quality improvement program, offered to small and large imaging centers over a large geographical area, can be successful.

References

1. Hausleiter J., Meyer T., Hermann F. et al. (2009) Estimated radiation dose associated with cardiac CT angiography . JAMA 301(5):500-507
2. Raff GL, Chinnaiyan KM, Share DA et al. Radiation dose from cardiac computed tomography before and after implementation of radiation dose-reduction techniques . JAMA 310(22):2340-2348
   

CT colonography: technical improvement and new application

Among the articles added this month to MDCT.net's literature database, two describe developments in CT of the colon.
Juchems and colleagues from Ulm, Germany, together with researchers at Philips Medical Systems, tested an electronic colon cleansing software for digital subtraction of opacified fluid and barium-tagged feces in the colon [ 1 ]. Using optical colonoscopy as the gold standard, the researchers compared the diagnostic accuracy of 4- or 8-slice MDCT colonography without and with the cleansing algorithm, on an archive of 79 datasets from patients with colonic polyps. The software favorably impacted on the sensitivity of detecting polyps by two blinded readers.
Researchers from the Mayo Clinic in Arizona investigated the accuracy of diagnosing colitis with 8-slice MDCT enterography and both oral and intravenous contrast agents [ 2 ]. This retrospective study evaluated data from 35 patients without and 35 with colonoscopy-confirmed ulcerative or Crohn's colitis. Overall sensitivity was 74%, but this increased to 89% in the subgroup of patients with excellent colon distension and to 93% in patients with moderate-severe disease. Accuracy in classifying disease activity as mild, moderate or severe was limited, suggesting the need to improve imaging protocols for this application.






References

1. Juchems MS, Ernst A., Johnson P. et al. (2009) Electronic colon-cleansing for CT colonography: diagnostic performance. Abdom Imaging 34(3):359-364
   
2. Johnson KT, Hara AK, Johnson CD (2009) Evaluation of colitis: usefulness of CT enterography technique. Emerg Radiol 16(4):277-282
   

Coronary MDCT and acute chest pain

Clinical guidelines for the emergency management of chest pain call for the use of coronary MDCT angiography as a supplemental test, after an observation period, for individuals with a low probability of acute coronary syndrome [ 1 ]. Researchers from Tel Aviv, Israel, reported their experience with 64-slice CT angiography in the workup of patients with chest pain [2]. In their practice, patients are monitored in a chest pain unit for 12 h with electrocardiography and cardiac troponin determinations, and then are directly hospitalized or discharged or undergo noninvasive testing with myocardial perfusion scintigraphy (MPS) or CT angiography, depending on clinical characteristics and instrumental availability.
The report describes the evaluation of 785 patients with acute chest pain who, after observation, were hospitalized (42 cases) or discharged (44 cases), or underwent further imaging with MPS (359 cases) or CT angiography (340 cases). Patients in the MPS group were older and had worse clinical conditions, because this group included persons with contraindications to CT angiography. However, similar proportions of patients (89% and 90%, respectively) were discharged after imaging due to absence of major disease. In the follow-up period, a similar proportion of the discharged patients experienced repeat chest pain (33% and 28%, respectively) and a few patients were readmitted for suspected cardiovascular chest pain (3 and 15, p=0.01). The authors suggested that MDCT angiography could be part of the emergency investigation of acute chest pain in accurately selected patients.

References

1. Anderson JL, Adams CD, Antman EM et al. (2007) ACC/AHA 2007 guidelines for the management of patients with unstable angina/non–S T-elevation myocardial infarction: executive summary . Circulation 116:803-877
   
2. Beigel R., Oieru D., Goitein O. et al. (2009) Usefulness of routine use of multidetector coronary computed tomography in the "fast track" evaluation of patients with acute chest pain . Am J Cardiol 103(11):1481-1486
   

Cancer imaging course in Salzburg

The International Cancer Imaging Society will hold its ninth annual teaching course and annual meeting in Salzburg, Austria, on 1-3 October 2009. The program is focused on the multidisciplinary management of cancer. A first keynote lecture on the use of CT colonography for cancer screening will be given by J.P. Heiken of Washington University School of Medicine. Another keynote lecture on the development of practice guidelines for cancer will be given by L. Ollivier from the Institut Curie. Scientific sessions will address imaging applications for tumors of the brain, spine and lung, pediatric imaging, the management of incidental lesions, imaging applications for oncological emergencies, and tumor ablation. Two hands-on workshops will be given on CT colonography and diffusion-weighted MRI, while other workshops will focus on the female pelvis, pancreatic cancer, molecular imaging, and the diagnosis of abdominal tumors. A full program and registration information are available at www.icimagingsociety.org.uk

CIN & Long-Term Adverse Events: Cause and Effect?

A study on 294 patients administered with either ipopamidol or iodixanol and followed up for 1 year or longer showed a higher rate of long term cardiovascular adverse events (AEs) in patients experiencing CIN [1]. Randomization to iopamidol reduced both the incidence of CIN and the rate of major AEs.



References

1. Solomon RJ, Mehran R, Natarajan MK et al (2009) Contrast-induced nephropathy and long-term adverse events: cause and effect? Clin J Am Soc Nephrol. 4:1162-1169 PMID: 19556381
   

7 ^th European Course of Cardiac CT and MR

The seventh European Course of Cardiac CT and MR (CardioCTMR) was held on 11-12 June 2009, in the center of Paris at the Maison de la Chimie. Over one and a half days, experienced radiologists and cardiologists from five European countries and the United States gave high quality lectures on the state-of-the-art in both cardiac CT and MRI. This was a refresher course for getting up to date in a friendly atmosphere.
The first half-day of the course focused on coronary artery imaging, mainly with CT. Although the complimentary role between cardiac CT and cardiac MRI is now obvious, CT at the present time seems to be the more reliable technique for visualizing the coronary arteries in a noninvasive fashion. The next morning concerned the myocardium, valves and aorta, and included an outstanding presentation on imaging for percutaneous treatment of aortic stenosis by Prof. J.N. Dacher from the University Hospital of Rouen, a pioneering center for this new technique. Finally, the last afternoon of the course dealt with technical issues and included a manufacturers' session which showed the near future beyond 64-slice CT technology and 1.5 T MR imaging.
This successful meeting was highly appreciated by 250 attendees specialized in this field, from 15 countries in Europe and even beyond. The next course will be held in the same location, on 3-4 June 2010, in parallel with a new international meeting on radiation protection and safety issues for patients. Presentations from CardioCTMR 2009, and from CardioCTMR 2008, will soon be available at www.cardioctmr.com.

Coronary CT angiography performance guidelines

This year, the Society of Cardiovascular Computed Tomography (SCCT) published two practice guidelines in its official publication, the Journal of Cardiovascular Computed Tomography. The first report focused on interpreting and reporting the results of coronary CT angiograms (see MDCT.net news from May of this year) [ 1 ]. The second report, now freely available online, sets standards for image acquisition and data processing, and suggests approaches for optimizing image quality and diagnostic yield [ 2 ].
The 15-page document is organized in six main sections, each with a set of recommendations. The first part addresses competencies for physicians and technicians, as well as technical standards for CT scanners. In particular, scanners must have at least 16 detector rows, but 32 or more detector rows are recommended. Moreover, radiation dose should be recorded using the dose-length product for every patient, as recommended in the earlier report. Successive sections focus on screening for contraindications, providing preprocedural instructions and medications, and positioning patients for the examination. Another section describes the administration of contrast medium and recommends using contrast agents with high iodine concentration, injection flow rates of 4-7 ml/s, and bi- or triphasic injection protocols. Regarding image acquisition, the document describes techniques for reducing radiation exposure and discusses the main scanning parameters, including when to use prospective ECG triggering or retrospective ECG gating and how to adjust the imaging protocol to a patient's heart rate and body weight. Finally, the document addresses image reconstruction and editing.
The authors conclude by noting that successful imaging is only possible with a thorough understanding of the advantages and limitations of CT angiography, combined with the proper selection and preparation of patients and the correct scanning and image processing. They call for both expertise and vigilance to ensure an accurate and safe execution of the examination.





References

1. Raff GL, Abidov A., Achenbach S. et al. (2009) SCCT guidelines for the interpretation and reporting of coronary computed tomographic angiography. Society of Cardiovascular Computed Tomography. J Cardiovasc Comput Tomogr. 3(2):122-136
   
2. Abbara S., Arbab-Zadeh A., Callister TQ et al. (2009) SCCT guidelines for performance of coronary computed tomographic angiography: A report of the Society of Cardiovascular Computed Tomography Guidelines Committee.J Cardiovasc Comput Tomogr 3(3):190-204
   

Selected literature update
Automated MDCT measurements: new applications

Two methodological papers on automated MDCT measurements have been included in the literature library of MDCT.net. The papers were published last month in European Radiology.
Researchers from Germany tested the accuracy of different CT protocols in measuring the diameter and volume of lymph nodes in a phantom model [ 1 ]. The phantom had 17 different lesions, which were imaged with 16 scanning protocols that varied in tube current, reconstruction kernel, or slice thickness; data were analyzed using the lymph node algorithm provided with SyngoOncology software. Concordance between actual and MDCT values of diameter and volume, expressed as correlation coefficients, ranged from 0.94 to 1.00. This high concordance achieved in a phantom model suggests that automated MDCT lymph node sizing may be possible in the clinical setting.
Researchers from three French cities tested the reproducibility of automated measurements of airway dimensions [ 2 ]. In the study, 5 women with breast cancer underwent 64-slice MDCT twice on the same day. Image reconstruction and 3D modelling of the bronchial tree were done using BronCare software, developed by the same authors. A strong correlation (r>0.96) was found between the first and second measurements of both lumen area and wall area; this was achieved using either a semi-automated or a fully automated method. The authors also looked at serial changes in bronchial dimensions along 10 successive slices, expressed as the coefficient of variation (CV10); the correlation between CV10 values from the first and second acquisitions was good (r=0.89 for lumen area; r=0.72 for wall area). The authors propose using CD10 values in longitudinal studies of bronchial remodelling.

References

1. Keil S., Plumhans C., Behrendt FF et al. (2009)   Automated measurement of lymph nodes: a phantom study . Eur Radiol 19(5):1079-1086
   
2. Brillet PY, Fetita CI, Capderou A. et al. (2009) Variability of bronchial measurements obtained by sequential CT using two computer-based methods . Eur Radiol 19(5):1139-1147
   

Accuracy of CT colonography screening in high-risk persons

Guidelines published in 2008 by three US medical associations concluded that CT colonography was a valid method for screening the general population for colorectal cancer (CRC) (see MDCT.net news of April 2008) [ 1 ]. However, the accuracy of CT colonography in high-risk individuals had not been reported.
The diagnostic accuracy of CT colonography as a CRC screening method in high-risk persons was evaluated in a multicenter, cross-sectional study, recently published in JAMA [ 2 ]. The study involved 1 Belgian and 11 Italian centers that enrolled persons at increased risk of advanced neoplasia due to a family history of CRC, a previous polypectomy for colorectal adenoma, or a positive fecal occult blood test (FOBT) result. Each individual underwent non-contrasted CT colonography (on 16-slice scanners in over 70% of cases), followed by colonoscopy within 3 hours.
Overall, 937 persons underwent both diagnostic examinations and 177 (18.9%) were found to have advanced adenoma or carcinoma. CT colonography had a specificity of 85.3% and a sensitivity of 87.8% for lesions at least 6 mm in diameter; the negative predictive value was 96.3% overall but 84.9% in the group of subjects with a positive FOBT result. The authors concluded that CT colonography may be considered an alternative screening method also in subjects at high risk for CRC.

References

1. Levin B., Lieberman DA, McFarland B. et al. (2008) Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology . CA Cancer J Clin 58(3):130-160
2. Regge D., Laudi C., Galatola G. et al. (2009) Diagnostic accuracy of computed tomographic colonography for the detection of advanced neoplasia in individuals at increased risk of colorectal cancer . JAMA 301(23):2453-2461
   

Profile: French Society of Radiology

The Société Française de Radiologie (SFR, www.sfrnet.org) is the leading French professional association for radiologists. The association's aims are to promote radiology through advancing knowledge, validating scientific information, and training physicians. SFR celebrated 100 years of activity this year and has more than 7000 members in 21 regional groups.
SFR achieves its goals by publishing the monthly Journal de Radiologie, as well as a society bulletin and the French edition of Imaging Management. In addition, each year it holds the Journées Françaises de Radiologie, an annual conference in Paris. This year's meeting will be held on 16-20 October and is expected to have 17 000 participants, 100 scientific sessions and 500 posters.
SFR encompasses several specialty imaging associations dedicated to otorhinolaryngology, neuroradiology, pediatrics, cardiovascular medicine and to the pathologies of skeletal muscle, breast, thorax, abdomen and genitourinary tract. Moreover, it has about 30 working groups that set SFR policy and suggest topics for the annual conference. The working group on contrast agents (CIRTACI) has prepared a set of practice guides, available online, and has established an observatory for monitoring allergic reactions.

Interpreting and reporting the results of CT angiography

The Society of Cardiovascular Computed Tomography (SCCT) recently published its first guidelines on CT coronary angiography. The 15-page document, authored by 10 physicians from the US and Germany, was developed as an “educational tool” for practitioners and is offered as a contribution towards the establishment of practice standards.
The first part of the document addresses the interpretation of CT angiograms: it begins by reviewing fundamental concepts, such as post-processing image formats and coronary calcium scoring, discusses in detail how to evaluate coronary artery anatomy and pathology, and closes with comments on non-coronary findings. The second part set standards for reporting CT angiography findings, so that referring physicians receive rigorous, clear documentation; for this purpose, the writing committee proposed a structured report, with sections on the patient's clinical status, the imaging procedure (e.g. equipment, patient preparation, acquisition, reconstruction), the results (including technical quality and all clinical findings), and the radiologist's interpretation.




References

1. Raff GL, Abidov A., Achenbach S. et al. (2009) SCCT guidelines for the interpretation and reporting of coronary computed tomographic angiography. Society of Cardiovascular Computed Tomography. J Cardiovasc Comput Tomogr. 3(2):122-136
   

Selected literature update
64-slice CT coronary angiography: latest research

The use of multislice CT angiography to study the coronary arteries has been much discussed in the scientific literature and in MDCT.net's news column (see, for example, stories from March 2009 and December 2008) . Three new reports on 64-slice CT coronary angiography have been included in MDCT.net's literature database this month.
The April issue of European Radiology contains a report describing the objectives and methodology of the CORE-64 trial [ 1 ]. This multicenter trial, conducted in nine centers in North and South America, Europe and Asia, aimed to determine the diagnostic accuracy of 64-slice CT angiography in detecting stenosis in patients with coronary artery disease. Patients underwent contrast-enhanced imaging on 64 scanners and then conventional coronary angiography within 30 days. The authors emphasized that the large size and multicentric nature of CORE-64 should overcome limitations of earlier studies that highlighted an inadequate specificity of 16- to 64-slice CT angiography. It is unknown when the trial's result will be published.
In La Radiologia Medica, Italian and Dutch researchers reported the use of 64-slice CT coronary angiography to investigate aspects of atherosclerotic plaque composition that lead to vulnerability [ 2 ]. They focused on the left main coronary artery, which infrequently has vulnerable plaques, and found that the presence of plaque was associated with increased artery diameter; there also was a moderate correlation between diameter and plaque area.
Finally, researchers at the Medical University of South Carolina tested a prototype instrument that combined 64-slice CT with SPECT for simultaneous assessment of coronary anatomy and myocardial perfusion [ 3 ]. Such a system would obviate the need for image fusion algorithms to combine separate CT and SPECT results and should facilitate assessment of the hemodynamic impact of coronary artery disease.

References

1. Miller JM, Dewey M., Vavere AL et al. (2009) Coronary CT angiography using 64 detector rows: methods and design of the multi-centre trial CORE-64 . Eur Radiol 19(4):816-828
   
2. Cademartiri F., La Grutta L., Malagò R. et al. (2009) Assessment of left main coronary artery atherosclerotic burden using 64-slice CT coronary angiography: correlation between dimensions and presence of plaques . Radiol Med 114(3):358-369
   
3. Thilo C., Schoepf UJ, Gordon L. et al. (2009) Integrated assessment of coronary anatomy and myocardial perfusion using a retractable SPECT camera combined with 64-slice CT: initial experience . Eur Radiol 19(4):845-856
   

Cardiac CT angiography and radiation dose

Despite the increasing use of MDCT angiography worldwide, there is inadequate knowledge of the magnitude of radiation exposure during an examination, the factors that contribute to this exposure, and the effectiveness of dose-reduction protocols. Researchers from the US and Germany, funded by the German Heart Center in Munich, did an observational study to determine radiation dose in daily practice.
The PROTECTION I study, published in JAMA [ 1 ], involved 50 university and community CT centers in 26 countries and enrolled 1965 unselected patients who underwent cardiac CT angiography for various clinical indications with different CT protocols and scanners. Radiation dose was measured as the dose-length product (DLP) while the effective dose was calculated using a conversion factor given in the 2004 CT quality criteria.
Median DLP was 885 mGy · cm per scan (corresponding to 12 mSv effective dose), but there was wide variability in the median value per site, ranging from 331 mGy · cm (5 mSv) to 2146 mGy · cm (30 mSv). There also was wide variability among sites using the same CT scanner, which was attributed to incomplete use of dose-reduction strategies. Multivariable linear regression analysis revealed that DLP increased with scan length (5% per centimeter), yet decreased when sequential scanning was used (-78% vs. spiral scanning), tube voltage was reduced to 100 kV (-46% vs. 120 kV) and tube current was modulated by ECG (-25%); automated exposure control did not reduce radiation dose. A diagnostic reference DLP of 1200 mGy · cm was proposed based on the 75th percentile of values in the study.
The authors concluded that, although CT angiography can exposure patients to a high level of radiation, dose-reduction techniques – in particular ECG modulation of tube current – are effective and should be more widely used. They proposed that DLP be recorded in every CT report to help CT centers monitor radiation dose, and called for better training on the use of dose-reduction strategies.

References

1. Hausleiter J., Meyer T., Hermann F. et al. (2009) Estimated radiation dose associated with cardiac CT angiography. JAMA 301(5):500-507
   

Profile: Society of Cardiovascular Computed Tomography

The Society of Cardiovascular Computed Tomography (SCCT, www.scct.org) is an international professional association whose mission is to promote research, education and clinical practice regarding cardiovascular applications of CT. Members are medical physicians, administrators, scientists and technologists actively engaged in the practice or management of cardiovascular CT.
SCCT produces the Journal of Cardiovascular Computed Tomography, a bimonthly that began in 2007. This July, the association will hold its fourth annual meeting in Orlando; the nearly 400 submitted abstracts will be published in the association's journal. The meeting will be preceded by a 2-day cardiac CT review board course. The SCCT also organizes refresher courses in CT angiography in different US locations.
Since 2005, the association has worked with other professional societies to establish clinical competence guidelines and appropriateness criteria regarding cardiovascular imaging.

US court decides in favor of Bracco Diagnostics in comparative advertising case against GE Healthcare

The NEPHRIC study, published in the New England Journal of Medicine in 2003 [ 1 ], investigated two contrast media produced by GE Healthcare and found that the safety profile of the iso-osmolar iodixanol was superior to that of iohexol, a low osmolar contrast medium.
Although the trial did not investigate other low osmolar agents, subsequent advertisements by GE Healthcare led to misinterpretation of the study by extending the results to other low osmolar contrast agents, such as iopamidol, produced by Bracco Diagnostics.
On 25 March 2009, a US federal court decided that generalizing to all low osmolar contrast agents was scientifically unjustified. The court ordered GE Healthcare to cease from making further false claims, to issue corrective advertisements in order to ensure that healthcare providers are informed about the false claims, and to compensate Bracco Diagnostics for its own expenses in corrective advertising, amounting to US$ 11.4 million.

References

1. Aspelin P., Aubry P., Fransson SG et al. (2003)  Nephrotoxic effects in high-risk patients undergoing angiography . N Engl J Med 348(6):491-499
   

CT colonography endorsed as “alternative cancer prevention test” in ACG guidelines

The American College of Gastroenterology (ACG) recently issued an update to their guidelines on colorectal cancer screening [ 1 ]. One of the innovations of the revised guidelines is the distinction of screening methods into cancer prevention and cancer detection tests: cancer prevention tests can detect both polyps and cancer and thus are preferred to cancer detection tests, which are ineffective in detecting polyps.
The recommended cancer prevention test is colonoscopy (every 10 years starting at age 50 in average-risk persons). Persons who refuse colonoscopy and those in whom colonoscopy is not feasible should be offered an alternative test. Two alternative cancer prevention tests are recommended: flexible sigmoidoscopy (every 5-10 years) and CT colonography (every 5 years). CT colonography, which replaced double contrast barium enema in the revised guidelines, was endorsed because of its 90% sensitivity for polyps 1 cm or larger [ 2 ]. Other attractive features of this method, according to the report, are the ability to detect extracolonic pathology, patients' preference and – subsequently – the possibility that more persons adhere to screening programs using this technology. Current limitations to CT colonography, for which it was not chosen as the first-line method, include the inability to detect small polyps, frequent false positives (86% specificity), and radiation exposure. Thus, until new studies show improved specificity or clinical impact, CT colonography should be used as an alternative cancer prevention test when colonoscopy is not possible.

References

1. Rex DK, Johnson DA, Anderson JC et al. (2009) American College of Gastroenterology guidelines for colorectal cancer screening 2008. Am J Gastroenterol 104(3):739-750
   
2. Johnson CD, Chen MH, Toledano AY et al. (2008) Accuracy of CT colonography for detection of large adenomas and cancers. N Engl J Med 359(12):1207-1217
   

Expert reviews on clinical applications of MDCT

This month's update to MDCT.net's literature archive includes reviews on two important clinical applications of MDCT. Writing in Current Atherosclerosis Reports, clinicians from the Cardioangiologisches Centrum Bethanien (Frankfurt) review evidence supporting the use of MDCT angiography in the assessment of atherosclerosis [ 1]. Their report discusses the effectiveness of CT angiography in diagnosing and characterizing calcified and non-calcified plaques, in ruling out severe stenosis in symptomatic patients in the emergency setting, and in predicting the prognosis of patients with atherosclerosis. Although it remains to be demonstrated that CT angiography is superior to conventional methods of risk stratification for atherosclerosis, the authors conclude that the current evidence is encouraging.
On the pages of European Radiology, radiologists from Beth Israel Deaconess Medical Center (Boston) review the state of the art in the CT evaluation of pulmonary emphysema [ 2]. Their report describes the use of CT to visualize this pathology and to objectively quantify the extent of disease based on attenuation values and complex textural analyses. It discusses how clinical parameters (e.g. patient's age and lung size) and scanning parameters (e.g. imaging during inspiration vs. expiration) impact upon the quantitative evaluation. Finally, it predicts that new-generation MDCT scanners will open new avenues of clinical investigation, such as evaluating lung ventilation and perfusion and studying the evolution of emphysema into chronic obstructive pulmonary disease.

References

1. Schmermund A., Magedanz A., Voigtländer T. (2009) The role of CT angiography in risk stratification for atherosclerosis . Curr Atherosclerosis Rep 11:111-117
   
2. Litmanovich D., Boiselle PM, Bankier AA (2009) CT of pulmonary emphysema - current status, challenges, and future directions . Eur Radiol 29(3):537-551
   

World Congress of Thoracic Imaging

The uses of medical imaging in the diagnosis and treatment of diseases of the chest are the topics of a truly international congress to be held in Valencia, Spain, between 30 May and 2 June 2009. The Second World Congress on Thoracic Imaging and Diagnosis of Chest Disease has been organized by the Fleischner Society, the Society of Thoracic Radiology, the European Society of Thoracic Imaging, the Japanese Society of Thoracic Radiology and the Korean Society of Thoracic Radiology; it is being hosted in Valencia by three Spanish medical associations.
The meeting will offer plenary sessions on interstitial lung disease, chronic obstructive pulmonary disease, cardiac imaging, lung cancer, and pulmonary embolism and hypertension. Numerous scientific sessions will deal with CT applications such as MDCT in the emergency setting, low dose CT, computer-aided diagnosis in chest CT, and CT angiography. The congress will offer 17 instructional courses, an image interpretation session and several manufacturers' symposia. The full program and an online registration form are available at www.2wcti.org.

AHA recommendations on the safe use of cardiac imaging

Decisions regarding the use of ionizing radiation in medical imaging – to keep the radiation dose as low as reasonably achievable – are the responsibility of individual radiologists, who must be up to date on technical issues and understand the risk:benefit balance. To assist radiologists in this important decisional role, the American Heart Association (AHA) prepared a science advisory entitled “Ionizing radiation in cardiac imaging”. AHA science advisories are position statements written and peer-reviewed by AHA members. This report, written by a group of 13 physicians and researchers from the USA, was recently published in Circulation [ 1 ].
The AHA report addresses three main issues: estimating radiation dose, understanding the risks of radiation exposure, and understanding the risks of not performing diagnostic imaging. First, the paper summarizes the parameters by which radiation dose is measured in CT, fluorography and radionuclide studies, and discusses how to interpret and report these parameters. It then reviews the risk of carcinogenesis from radiation exposure and relates this risk to the chances of dying from activities of daily life. It briefly deals with potential risks of not performing needed imaging studies, but acknowledges that there is no evidence of a survival benefit in patients exposed to ionizing radiation. The report concludes with a summary and list of recommendations rated according to the evidence schema of the American College of Cardiology Foundation/AHA.
The recommendations of this AHA science advisory include: (i) a statement against surveillance imaging in asymptomatic patients at low risk for heart disease, (ii) a comment that longitudinal monitoring of patients' cumulative exposures is currently not feasible, (iii) a call for the development of better radiation dose metrics, and (iv) a proposal that radiologists establish references levels for radiation exposure in different diagnostic examinations, to use in international benchmarking studies.

References

1. Gerber TC, Carr JJ, Arai AE et al (2009) Ionizing radiation in cardiac imaging: a science advisory from the American Heart Association Committee on Cardiac Imaging of the Council on Clinical Cardiology and Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention. Circulation 119:1056-1065
   

International exchange program for young radiologists

The European School of Radiology is continuing, for the third consecutive year, its international exchange program for radiologists in training. The Visiting Scholarship program supports a 3-month focused training period in radiology centers of excellence throughout Europe and, for the first time, in New York City.
Topics of study for 2009 are abdominal radiology, breast imaging, cardiac imaging, chest imaging, musculoskeletal radiology, neuroradiology, oncologic imaging, urogenital radiology, PET-CT protocols and MRI protocols. The 2009 edition will provide 29 trainees with scholarship funding to cover living expenses and travel costs. Funding is provided by Bracco together with the Memorial Sloan-Kettering Cancer Center and the European Society of Radiology (ESR). Information regarding eligibility and how to apply is available from the education section of the ESR website. The application deadline is 1 April 2009.

Coronary atherosclerosis investigated with MDCT

The diagnosis – or exclusion – of coronary atherosclerosis in patients with cardiovascular risk factors can help predict the probability of future cardiac events. Two studies addressing this issue in the International Journal of Cardiovascular Imaging have been included in the literature archive of MDCT.net.
Researchers at the University Hospital of Ulm, Germany, investigated if coronary atherosclerosis can be predicted from the thickness of the mid-descending aortic wall, since atherosclerosis is a “diffuse condition” that can simultaneously affect coronary, cerebral, carotid and peripheral arteries [ 1 ]. They retrospectively evaluated contrast-enhanced 40-slice CT coronary angiograms from 58 patients without and 102 patients with coronary atherosclerosis (diagnosed when coronary plaques were seen with CT). Aortic wall thickness increased with age (confirming previous knowledge) and was higher in patients with coronary atherosclerosis (particularly in those with calcified plaques). Thus, the authors hypothesized that coronary atherosclerosis can be predicted from aortic wall thickness measured on routine chest CT studies, without the need for specific cardiac imaging.
The second study, contributed by researchers in Turkey, used 16-slice MDCT calcium scoring to assess cardiovascular risk in 31 patients with subclinical primary hyperparathyroidism (PHP) and in 19 healthy controls. Median calcium score was zero in both groups, but there was wide interpatient variability in the PHP group. When this group was subdivided according to the absence or presence of hypertension, normotensives were found to have calcium scores similar to those of controls whereas hypertensives had significantly higher scores (and were older with a greater prevalence of obesity and hyperlipidemia). The authors concluded that asymptomatic PHP is not a risk factor for coronary atherosclerosis, so these patients can be treated conservatively.

References

1. Jeltsch M., Klass O., Klein S. et al. (2009) Aortic wall thickness assessed by multidetector computed tomography as a predictor of coronary atherosclerosis. Int J Cardiovasc Imaging 25(2):209-217
   
2. Kepez A., Harmanci A., Hazirolan T. et al. (2009) Evaluation of subclinical coronary atherosclerosis in mild asymptomatic primary hyperparathyroidism patients. Int J Cardiovasc Imaging 25(2):187-193
   

ECR 2009: dignitaries in the field of radiology

Each year, the European Society of Radiology acknowledges individuals who have made important contributions to the field of radiology. This year, ten radiologists were named as dignitaries.
Gold medals were given to Helen M.L. Carty (Liverpool) and Antonio Chiesa (Vicenza). Dr. Carty was recognized for outstanding advances in pediatric and orthopaedic radiology. Among her numerous professional roles, she was director of radiological services at Royal Liverpool Children‘ s NHS Trust and professor of pediatric radiology at Liverpool University. She is one of the innovators of a radiological intervention for aneurysmal bone cysts in children. Dr. Chiesa was awarded for exceptional contributions in head and neck radiology and for outstanding leadership in advancing Italian and European radiology. His recent professional roles were as director of the Radiology Department and as professor of radiology in the Schools of Medicine and Odontology, all at the University of Brescia.
The honor of giving the ECR opening lecture was awarded to Hedvig Hricak (New York), whose experience with anatomic and molecular imaging of genitourinary cancer formed the basis for a talk entitled 'Imaging in oncology: endless horizons'. Other honorary lecturers at ECR 2009 were Carlo Bartolozzi (Pisa), Dieter R. Enzmann (Los Angeles) and Anton Valavanis (Zurich).
Honorary membership in the European Society of Radiology, awarded for outstanding scientific contributions to the field of radiology, was given to Jürgen Hennig (Freiburg), Theresa C. McLoud (Boston), Ho-Young Song (Seoul) and James H. Thrall (Boston).
Biographies of these distinguished radiologists are available at www.myesr.org.

ECR 2009: Abdominal imaging

This year's European Congress of Radiology (ECR) has been a tremendous success again, with many excellent talks covering all aspects of radiology. Although the weather was wet during much of the meeting, most - if not all - participants seemed to have greatly enjoyed the opportunity to get up to date with today's topics in radiology. Abdominal imaging was present in the ECR program, although I did not encounter any particularly important advances.
Abdominal topics were not specifically addressed in the "new horizon" sessions, which dealt with cell and plaque imaging and which pointed into the future. This was also the case in the "state of the art" symposia, which centered on stroke management, lung cancer screening, and the interaction of the radiologist with the computer.
Of the 20 "special focus" sessions, one stressed the value of PET-CT in monitoring tumor responses. In the session on dual energy CT, potential applications for this novel technique within the abdomen were presented, but they do not seem ready for widespread clinical use. An excellent session - and the only one that dealt primarily with the abdomen - was named "Portal hypertension, an update". This session stressed the need for multimodality imaging in the work-up of pre-, intra-, and post-hepatic causes of portal hypertension. Both CT and MRI have their specific advantages, but MDCT is well established in this application.
Dedicated "categorical courses" were offered in the fields of spinal imaging and intervention, cardiac imaging, and breast imaging. "Mini courses" were organized on advances in CT and MRI for trauma imaging, and on extremity joint MRI. Again, these sessions offered nothing of specific interest for an abdominal radiologist.
Fortunately, the refresher courses dealt with many interesting topics from the abdominal field, including, for example, the growing role of PET-CT for esophageal cancer, imaging of hepatocellular carcinoma (still strong for MDCT), and the discussion of MRI versus CT in Crohn's disease. There was also a session on imaging and intervention in gastrointestinal bleeding that I was supposed to present myself, but unfortunately I was unable to do so because of acute food poisoning the night before.
In conclusion, this year's ECR did not have abdominal radiology in its primary focus, but both MDCT and abdominal radiology were well represented in many areas.

ECR 2009 : Cardiac CT

Radiation exposure is always an important topic in CT, especially in cardiac CT which delivers a substantial radiation dose. However, as documented by a study published in the February 4th issue of JAMA [ 1 ], the radiation dose from cardiac CT is highly variable among centers. This study, which surveyed 21 academic and 29 community hospitals in Europe, USA, Asia and South America, found that the median radiation dose to patients varied from 5 to 35 mSv depending on the center. Thus, every new technological improvement which may help reduce radiation dose is welcomed.
New strategies for radiation dose reduction in cardiac CT were shown at this year's European Congress of Radiology (ECR), held on 6-10 March in Vienna. In particular, CT manufacturers have introduced several new technological features:

• Sequential scanning protocols, prospectively triggered by ECG recordings, are now routinely proposed by all manufacturers. This technique blocks radiation exposure outside a specific time window, thereby reducing dose by about 75% without impairing image quality for the chosen time window. The applicability of this method is becoming more robust by automatic detection of arrhythmia, avoiding acquisition in an inappropriate temporal window. Acquisition using only one rotation (Toshiba Aquilion One), now possible with very large detector rows, has also improved robustness in sequential scanning. This technique is now routinely applicable in patients with low and regular heart rates. Broad adoption of sequential scanning, however, will take time since only a few centers are currently equipped with the necessary instrumentation: in the study published in JAMA [1], sequential scanning was used in only 6% of cases.

• Enhancement of the quality of detection is another way to reduce dose for a given image quality. This approach was chosen by GE, using new detectors based on Gemstone technology that enhances the detection of X-rays. In addition, new reconstruction algorithms (so-called iterative algorithms, coming from nuclear medicine imaging technology) improve the signal-to-noise ratio without increasing radiation dose. GE claims lower radiation doses with improved image quality. Cardiac images shown in Vienna, obtained with this technique together with the sequential mode, were associated with an exposure of 2 or 3 mSv to the patient, depending on the kilovoltage settings.

• Siemens showed the first cardiac images using the flash mode on the new dual source CT (Flash Definition). This new acquisition technique is based on fast spiral acquisitions (pitch of 3.2, using both tubes). Acquisition is triggered by ECG. The cardiac images are acquired in the diastolic phase in patients with very low and regular heart rates, to avoid motion during this fast acquisition (about 300 ms are required to scan the whole heart, so a long period without heart motion is required). This allows a one-beat acquisition based on speed instead of large coverage, which is the strategy used by Toshiba’s Aquilion One. One-beat acquisition avoids the step artifacts usually seen when acquisition is performed over several heart beats. Because exposition time is short, radiation dose is also low: Siemens claims that by using this new concept for acquiring cardiac images, the exposures will be in the sub-millisievert range. Of note, as for the sequential mode, this low-dose protocol is only suited for use in patients with low heart rate, which remains an important limitation.

Research into new technological solutions to reduce radiation dose is going in various directions. The most efficient radiation dose-sparing strategies will be adopted by manufacturers for the benefit of patients. These new solutions must be evaluated by radiologists, but it is reasonable to anticipate that the mean radiation dose to patients during cardiac CT will soon be lower than that associated with coronary angiography (5 mSv). Alongside better image quality, one can also expect a huge increase in the use of coronary CT in the near future, opening new frontiers such as screening for coronary artery disease, which is still one of the major causes of mortality in developed countries.

References

1. Hausleiter J., Meyer T., Hermann F. et al. (2009) Estimated radiation dose associated with cardiac CT angiography. JAMA 301(5):500-507
   

MDCT angiography and peripheral arterial disease: a meta-analysis

In patients with intermittent claudication or critical limb ischemia from peripheral arterial disease, treatment planning requires accurate diagnostic information regarding stenosis and occlusion. This information is provided by intra-arterial angiography or by noninvasive imaging modalities, such as duplex ultrasonography, magnetic resonance angiography and computed tomography angiography. In particular, MDCT angiography permits high-resolution visualization of the entire vascular tree of the lower extremities. Researchers in Amsterdam did a meta-analysis to assess the diagnostic performance of MDCT angiography; they published their findings in JAMA [ 1 ].
The meta-analysis included 20 diagnostic cohort studies that compared MDCT angiography to digital subtraction angiography in patients with intermittent claudication or critical limb ischemia; 12 similar studies were excluded for not having reported data in a format suitable for meta-analysis. Most included studies used 4- or 16-slice scanners, while two used 64-slice imaging. Overall, the methodological quality of the studies was moderate according to the QUADAS tool for assessing diagnostic accuracy studies [ 2 ].
This analysis found that MDCT angiography is highly accurate for diagnosing clinically significant (>50%) stenosis and occlusion throughout the lower vasculature. For the aortoiliac arteries, combined sensitivity was 96% and combined specificity was 98%. For the femoropopliteal arteries these values were 97% and 94%, while for the tibial arteries they were 95% and 91%, respectively. Sensitivity and specificity values were higher with 16- and 64-slice scanners than with 2- or 4-slice scanners, but did not vary according to disease severity or methodological aspects of the studies. Despite these good results, the authors noted that definitive conclusions cannot be drawn due to methodological limitations of the included papers; they emphasized that future studies on this topic adhere to the STARD checklist for reporting diagnostic accuracy studies [ 3 ].

References

1. Met R., Bipat S., Legemate DA, Reekers JA, Koelemay MJ (2009) Diagnostic performance of computed tomography angiography in peripheral arterial disease. A systematic review and meta-analysis. JAMA 301:415-424
   
2. Whiting P., Rutjes AWS, Reitsma JB et al. (2003) The development of QUADAS: a tool for the quality assessment of studies of diagnostic accuracy included in systematic reviews. BMC Med Res Methodol 3:25
   
3. Bossuyt PM, Reitsma JB, Bruns DE et al (2003) Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative. AJR Am J Roentgenol 181(1):51-55
   

Radiographic search engines

Today, most articles indexed in Medline are available electronically and so can be found with a general search engine like Google. However, comprehensive, sensitive and specific searching is only possible by invoking the controlled vocabulary and search fields available on PubMed and commercial literature databases. In the same manner, general search engines permit searching of radiographic images in medical journals, but the simple search algorithms give unsatisfying results. Two online tools – GoldMiner and Yottalook Images – now permit accurate searching of radiographic images within the electronic texts of peer-reviewed journals.
GoldMiner ( goldminer.arrs.org ), provided by the American Roentgen Ray Society, provides access to 200 000 freely available images from 261 peer-reviewed journals. A user's terms are searched both as free text keywords and as medical concepts after matching to three controlled vocabularies: Systematized Nomenclature of Medicine (SNOMED) clinical terms, the Foundational Model of Anatomy, and NLM's medical subheadings (MeSH). Quality search results are guaranteed by this dual keyword-context search function and by limiting results to a certain anatomical region, imaging finding, age class, gender, and type of image (CT, MRI, PET, US, X-ray, nuclear medicine, photograph, graph).
Yottalook Images ( www.yottalook.com ) is part of the radiological search engine offered by iVirtuoso. This tool permits searching among 750 000 radiographic images from free and subscription-based peer-reviewed journals. Effective searching is guaranteed by natural query analysis of the search terms and by sematic matching against a medical thesaurus based on RadLex (of the Radiology Society of North America). Search results may be limited to one imaging technique (plain radiography, CT, MRI, nuclear medicine, US) or to only freely available sources.
Both Goldminer and Yottalook Images are free to search, but the retrieved images must be used in accordance with each journal's copyright policies. Both tools are now testing multilingual search capabilities.

Profile: European Society of Neuroradiology

The European Society of Neuroradiology (ESNR, www.esnr.org ) is a professional association whose aim is to promote the speciality of clinical neuroradiology, including diagnostic, interventional, head and neck, and pediatric neuroradiology. Legally based in Switzerland, the ESNR's central office is in Milan and its current president is Prof. Marco Leonardi of Bellaria Hospital in Bologna.
The society's 34th congress and 18th advanced course will be held this year in September in Athens, while a joint symposium with the American Society of Spine Radiology (ASSR) will be held in July in Rome. Since 1984, the association has organized neuroradiology courses that permit participants to become certified in neuroradiology at a European level. Moreover, the association annually awards a young neuroradiologist the Lucien Appel Prize of the ESNR, worth eur. 4000. The ESNR's official publication is Neuroradiology, a journal published by Springer ( www.springer.com ).

Three-dimensional imaging with MDCT

Three-dimensional (3D) anatomical visualization with CT is a diagnostic imaging advance made possible by technological developments in both instrumentation and image processing software. Multidetector CT datasets can now be “reconstructed” to show particular imaging planes, tubular structures, fine vascular trees and specific anatomical surfaces. The resulting detailed and accurate images provide excellent support to surgical planning and permit a more precise diagnosis of a pathology and its impact on neighboring structures. To Morton A. Meyers, editor of Abdominal Imaging, these innovations represent a “new imaging paradigm” [1]. Thus, this journal dedicated the first issue of 2009 to 3D CT imaging.
Reports in this issue focus on novel imaging methods for a range of clinical topics, including esophageal pathology, gastric cancer, small bowel obstruction, appendicitis, peritoneal carcinomatosis, pancreatic and biliary pathologies, adrenal tumors, and urinary tract cancer. A number of virtual imaging techniques are described: virtual angioscopy, virtual endoscopy, virtual simulation, and virtual hysterosalpingography. In the words of Dr. Meyers, “read on and share the excitement”.



References

1. Meyers MA (2009) 3D CT imaging in clinical practice. Abdom Imaging 34:1-2
   

Musculoskeletal radiologists to meet in Genoa

This coming June, the European Society of Musculoskeletal Radiology (ESSR) will meet in Genoa, Italy, for a 2-day scientific conference and a refresher course entitled “Hip & Bone Pelvis”. The conference will be preceded by a meeting of the Italian Society of Medical Radiology. This one-day national event will offer scientific sessions, workstation sessions and imaging workshops, and keynote lectures will be given by Daniel Vanel on imaging soft-tissue tumors and by Folco Rossi on radiology in sports medicine. Participants of the joint meeting may also attend a course on ultrasonography of the hip.

The ESSR is accepting abstracts for scientific and educational presentations until 20 February 2009. Accepted abstracts will be published in Skeletal Radiology. More information about the joint conference is available at www.essr-sirm2009.it

Left ventricular dysfunction: comparative study of MDCT vs. MRI plus coronary angiography

Left ventricular dysfunction (LVD) may be due to myocardial ischemia or non-ischemic dilated cardiomyopathy. Defining the etiology of LVD in individual patients is therefore important for prognosis and treatment; this requires examination of both myocardial viability and coronary anatomy. Differentiation between ischemic and non-ischemic etiologies is possible with gadolinium-enhanced MRI: patients with ischemic disease typically have delayed enhancement (DE) in transmural or subendocardial segments, whereas DE is absent or atypical in those with non-ischemic disease. A full diagnosis, however, requires angiography to search for coronary artery disease (CAD).

Researchers from Belgium investigated the possibility of diagnosing LVD with contrast-enhanced MDCT, by combining information from both coronary (immediate) and delayed imaging [1]. They prospectively studied 71 patients who underwent angiography, MRI, and 40- or 64-slice MDCT with iomeprol (400 mg/ml iodine; Iomeron 400, Bracco, Milan, Italy) in a 1-month period. Findings from angiography and MRI were used to classify patients into four groups according to the presence or absence of CAD and of DE characteristic of LVD. Similarly, patients were classified according to the combined MDCT findings, and the results were compared.

Overall, there was good agreement in patient classification between the angiography-MRI protocol and the combined MDCT protocol (κ=0.89), with only 5 patients misclassified. Thus, combined coronary and delayed MDCT was found to have 97% sensitivity, 92% specificity, and 94% accuracy for diagnosing patients with definite or probable ischemic LVD. The authors discussed the advantages and limitations of using contrast-enhanced MDCT to diagnose LVD.

References

1. le Polain de Waroux JB, Pouleur AC, Goffinet C. et al (2008) Combined coronary and late-enhanced multidetector-computed tomography for delineation of the etiology of left ventricular dysfunction: comparison with coronary angiography and contrast-enhanced cardiac magnetic resonance imaging. Eur Heart J 29(20):2544–2 551
   

Biomarkers with potential to identify patients at risk of CIN

Understanding a patient's risk of contrast-induced nephropathy (CIN) is essential for weighing risks against benefits of a diagnostic or therapeutic procedure, and for choosing a prophylactic measure. Of the known risk factors for CIN, reduced kidney function is considered the most predictive.

Kidney function is usually estimated from serum creatinine levels, although other serum and urinary biomarkers have been proposed. Researchers in Japan monitored a series of potential biomarkers to find those that predict the occurrence or onset of CIN [1]. They prospectively studied 87 patients scheduled for coronary angiography, and found that serum levels of cystatin C prior to catheterization were higher in patients who developed CIN. Using a cutoff of >1.2 mg/l, cystatin C had 94.7% sensitivity and 84.8% specificity for predicting CIN. Moreover, in patients who experienced CIN, urinary levels of liver fatty acid binding protein were elevated in the 2 days following catheterization.

In the search for biomarkers, proteomics is considered state of the art. Applying this approach, researchers in the USA investigated 90 children with congenital heart disease who required cardiac catheterization and angiography [2]. Urine samples were analyzed before the procedure and in the subsequent 24 h using SELDI-TOF mass spectrometry and protein chromatographic microarrays (ProteinChips). This identified two small proteins whose pre-procedural urinary levels were significantly different between subgroups of patients who did and did not experience CIN. In particular, a variant of beta-defensin-1 was significantly lower in patients who had CIN, while an unknown 4.6 kDa protein was significantly higher in these patients.

These interesting results, if confirmed, may help avoid CIN by identifying predisposed patients.

References

1. Kato K., Sato N., Yamamoto T. et al (2008) Valuable markers for contrast-induced nephropathy in patients undergoing cardiac catheterization. Circ J 72(9):1499-505
   
2. Bennett MR, Ravipati N., Ross G. et al (2008) Using proteomics to identify preprocedural risk factors for contrast induced nephropathy. Proteomics Clin Appl 2(7-8):1058-1064
   

Selected literature update
MDCT and chronic lung diseases: three methodological advances

Three papers from a recent issue of European Radiology have proposed new methods for quantifying lung disease. Researchers from the University of Lille tested the prototype software in quantifying the extent of emphysema [1]. The software offers automatic and semi-automatic scoring, which compared favorably with visual assessment in 47 patients with severe chronic obstructive pulmonary disease (COPD).

Researchers from Germany and Sweden focused on airway-wall remodelling in COPD [2]. They illustrated the capabilities of YACTA, a software programmed by members of their own group and previously shown to quantify emphysema and facilitate lung segmentation. In this new study using YACTA, airway wall thickness was higher in COPD patients who smoked than in non-smoker controls; moreover, wall thickness correlated with forced expiratory volume.

Finally, researchers in Germany devised an algorithm to automatically classify lung tissue as normal or pathological [3]. Their tool determines the topology of CT attenuation values based on Minkowski functionals. This information, when combined with densitometric data, permitted the accurate identification of diseased lung tissue in patients with emphysema or fibrosis.

These papers are among the full text articles added this month to the database of selected literature in MDCT.net.


References

1. Revel MP, Faivre JB, Remy-Jardin M. et al (2008) Automated lobar quantification of emphysema in patients with severe COPD . Eur Radiol 18:2723-2730
   
2. Achenbach T., Weinheimer O., Biedermann A. et al (2008) MDCT assessment of airway wall thickness in COPD patients using a new method: correlations with pulmonary function tests. Eur Radiol 18:2731-2738
   
3. Boehm HF, Fink C., Attenberger U. et al (2008) Automated classification of normal and pathologic pulmonary tissue by topological texture features extracted from multi-detector CT in 3D. Eur Radiol 18:2745-2755
   

MDCT angiography and coronary artery disease: meta-analysis of clinical impact

MDCT angiography has generally been shown to be highly accurate in the diagnosis of coronary artery disease (CAD). Diagnostic accuracy, although important, is not the only factor that contributes to a technology's adoption as a routine test; also important are technical feasibility, safety and impact on clinical management and outcome. Already this year, two systematic reviews and one expert statement have addressed appropriate clinical uses of MDCT angiography (see MDCT.net news from October , June and February of this year). A recent paper in the International Journal of Cardiology [1] reported the results of a new meta-analysis on the clinical impact of this technology.
Researchers from three European countries searched the English literature (2000-2007) for papers that evaluated ≥16-slice MDCT in patients with confirmed or suspected CAD. Papers were selected if they provided data on accuracy, safety, technical applicability, clinical impact or costs. Overall, 150 studies were included in the analysis; however, only one of these studies assessed clinical impact and none contained an economic evaluation.
The meta-analysis confirmed the high diagnostic accuracy of MDCT for CAD. In particular, sensitivity was 93.1% and specificity was 82.9%; when only 40- and 64-slice scanners were considered, sensitivity and specificity were 97.2% and 91.4%, respectively. Safety data, available for 103 studies, gave an overall adverse event rate of 0.67%. In terms of technical applicability, 84% of patients were clinically eligible for MDCT (data from 45 studies) and the MDCT scans were assessable for 95% of patients (from 129 studies).
The authors commented that, despite the wealth of data on accuracy, there is limited information on the clinical impact of MDCT in patients with CAD. Indeed, they stated that MDCT research is “halted at the very first step of the ideal evaluation process of a new diagnostic technique”. Additional research is especially needed on cost-effectiveness and on the integration of MDCT angiography into clinical pathways.

References

1. Di Tanna GL, Berti E., Stivanello E. et al. (2008). Informative value of clinical research on multislice computed tomography in the diagnosis of coronary artery disease: a systematic review. Int J Cardiol 130:386-404
   

64-slice MDCT assessment of bone microarchitecture: possibile diagnostic use for osteoporosis

By current standards, a diagnosis of osteoporosis is based on low bone mineral density (BMD), as revealed by either dual-energy X-ray absorbtiometry or quantitative computed tomography. Besides low BMD, patients with osteoporosis also have deteriorations of bone microarchitecture. Both low BMD and microarchitectural alterations contribute to bone fragility. Thus, assessment of microarchitectural derangements might help determine the risk of bone fractures.
Researchers from Germany and the USA tested the feasibility of characterizing trabecular bone microarchitecture using 64-slice multidetector CT [1]. Their simulated in vivo study, using 15 intact human cadavers, followed a series of in vitro studies in which MDCT was shown to accurately characterize bone specimens. In this study, four parameters of bone structure were determined for the proximal femur, first on the cadavers with two MDCT imaging protocols and then on dissected specimens using high-resolution peripheral quantitative computed tomography (HR-pQCT).
Significant correlations were found between the gold-standard HR-pQCT and MDCT (135 kVp, 430 mA) for bone volume fraction (r=0.87), trabecular separation (r=0.66) and trabecular number (r=0.53) but not for trabecular thickness (r=0.23). Similar results were obtained for MDCT with 120 kVp and dose-adapted milliamperes.
The authors concluded that MDCT can be used in the clinical setting to assess certain parameters of bone microarchitecture. Further research is, however, necessary to determine if a combined assessment of BMD and bone microarchitecture is clinically advantageous over the standard BMD evaluation.

References

1. Diederichs G., Link T., Kentenich M. et al. (2008) Feasibility of measuring trabecular bone structure of the proximal femur using 64-slice multidetector computed tomography in a clinical setting . Calcif Tissue Int 83:332–341
   

RSNA 2008: Focus on education at the 94th annual meeting of the RSNA

The theme of this year's annual meeting of the Radiological Society of North America, which closed 5 December 2008 in Chicago, was “personal learning in the global community”. For Dr. Theresa McLoud, President of RSNA 2008, this motto refers to the choices that a medical professional makes regarding continuing education, in light of the current abundance of learning opportunities.
Radiology education was the focus of the President's address and opening session. Dr. McLoud spoke on trends in radiology training, from an international perspective, and argued for global standards; she also emphasized the importance of “sub-specialization”.
Dr. Jannette Collins, who was selected as RSNA's outstanding educator in 2005, spoke about lifelong learning, which implies a conceptual change from mastering a fixed set of skills to integrating education into one's career path. She advocated being active in scientific associations, teaching others, undergoing peer assessment and performing self-assessment.
Dr. Steven L. Dawson, who created the Center for Innovative Minimally Invasive Therapy, spoke of the educational opportunities afforded by medical simulation. According to Dr. Dawson, simulation technology facilitates the learning of skills and permits the assessment of performance. He encouraged expert radiologists to work with engineers to create specific radiological simulation devices and to commit to use them while teaching.
For the approximately 28 000 medical professionals who attended RSNA 2008, the 28 focus sessions, 86 multisession courses, 252 refresher courses, 209 scientific papers, 626 scientific posters and 1663 education exhibits offered an excellent opportunity for continued professional learning.
Based on articles published in the RSNA Daily Bulletin .

RSNA 2008: RSNA honorary membership awarded for significant contributions to radiology

The Radiological Society of North America (RSNA), despite its name, is an international association with members from 121 countries. Its international outlook was reinforced by its decision to award honorary membership to radiologists from two European nations and from China for their outstanding contributions to the field of radiology. This year's honorary members were Maximilian F. Reiser, Gustav K. von Schulthess and Jian-Ping Dai [1].
Dr. Reiser is currently Chair of the Department of Clinical Radiology at Ludwig Maximilian University of Munich and Dean of the Munich University Medical School. He was president of this year's European Congress of Radiology and has also served as President of the European Society of Musculoskeletal Radiology. His research interests include skeletal and abdominal imaging, and his most recent publications included comparative studies of MRI and CT for abdominal, cardiac and cranial imaging.
Dr. von Schulthess directs the Division of Nuclear Medicine and the MR Centre at University Hospital Zürich, and is a professor of nuclear medicine at the University of Zürich. He is also co-director of the International Diagnostic Course in Davos. One of his main research interests is multimodal or “fusion” imaging, e.g. PET/CT and SPECT/CT, regarding which he has recently written several review papers.
Dr. Dai is professor of neuroradiology in the Beijing Neurosurgical Institute (Beijing Tiantan Hospital, Capital University of Medical Sciences). Among his other appointments, he was director of medical services for all athletes participating in the 2008 Olympic Games. Dr. Dai is considered to have had a major role in promoting quality in radiology services and, in particular, to have introduced neurointerventional radiology in China.


References

1. Honorary members, RSNA 2008
   

RSNA 2008: Toshiba, GE, Philips and Siemens: four manufacturers, four different strategies

RSNA 2008 is clearly marking a new step in MDCT technology, after a 8-year run in which industry was driven mainly by one concept: increasing the number of slices (4-slice, 16-slice, 40-slice, then 64-slice CT). For heart imaging, the most obvious benefit of larger coverage is the lower incidence of step artefacts in the z-axis. 64-slice CT is now considered a minimal basis for routine cardiac imaging, and cardiac CT imaging is now performed on a routine basis using this technology in many sites.
Limitations of cardiac imaging using 64-slice CT are well known. High cardiac rhythm, coronary calcification and radiation dose associated with retrospective cardiac acquisition are the main factors limiting the widespread use of this technique, especially for non-cardiac imaging specialists.
To overcome these limitations, technology has pushed into various directions, depending on the manufacturer’s choices:

• For GE, the main axis of development is image quality. Although the number of detectors is the same (64 rows) with the new VCT Discovery 750 HD, new Gemstone detectors are provided, which improve X-ray detection by shortening the afterglow period. This favours radiation dose reduction for the same image quality. In addition, iterative algorithms are now provided in order to diminish artefacts (for example, metallic artefacts). Additionally, fast kilovolt switching will allow a new approach called “spectral imaging”, in which dual-energy acquisition is achieved with a single source.
• Toshiba's approach, already presented at RSNA 2007, is based on maximizing z-coverage: up to 16 cm are covered, making it possible to scan the heart in one beat. With full coverage of the heart in one beat, step artefacts should no longer be seen. Also, due to the full coverage, the heart's exposition time – and thus radiation dose – should be largely lowered.
• Philips has chosen an intermediate solution using an 8-cm coverage (128 detectors of 0.625 mm, with a double projection) and a curved detector. Temporal resolution has also been improved with a gantry rotation of 270 ms, which is the fastest on the market. For cardiac CT dose reduction, a step-and-shoot mode using only 2 prospective acquisitions makes low-dose acquisition possible.
• Siemens keeps a dual-source strategy by increasing the number of detectors (64 detectors, 128 slices for each source) and the speed of spiral acquisition. A new mode of cardiothoracic acquisition has been proposed, using a pitch of 3, with cardiac synchronisation, making it possible to acquire the whole thorax including the heart in 0.6 s. In principle, the heart may be scanned without motion artefacts during the diastolic phase if the heart rate is low and regular. This new type of acquisition may be associated with a very low range of radiation dose.

In conclusion, MDCT technology is constantly evolving, but now in different directions. More robust cardiovascular imaging and substantial radiation dose reduction will be certainly achieved with the new generation of CT machines presented at RSNA 2008. The tough competition between manufacturers, which have chosen very different strategies, is the best guarantee for optimal improvements in the near future, for the benefit of all patients.

RSNA 2008: Technical innovations in CT showcased at RSNA 2008

During RSNA 2008, the annual meeting of the Radiological Society of North America held in Chicago from November 30th to December 5th, the major manufacturers presented their latest developments in CT technology. These innovations are briefly summarized.

General Electric
GE introduced the new Gemstone detector that presents a primary speed 100-times greater and an afterglow 4-times lower than the previous detector. This change results in a 2.5-fold increase of views, a 40% increment of contrast resolution and a spatial resolution up to 230 microns. Due to these improvements, GE has applied the new name HD (high definition).
GE also presented a new generator designed for dual energy with ultra-fast switching; this allows switching from 80 to 140 kVp in less than one millisecond.
The new X-ray tube, also designed for dual energy with ultra-fast switching, allows, with its dynamic focal spot, the acquisition of 128 slices/rotation, of which 64 can be acquired at low energy and 64 at high energy, with a 50 cm FOV.
All these technical innovations will allow the following applications:

• Adaptive statistical iterative reconstruction (ASIR): a new algorithm for image reconstruction, which should permit a 50% dose reduction.
• Volume helical shuttle: an alternative table motion during dynamic acquisition, which allows assessment of perfusion of entire organs.
• Spectral imaging: a system for acquisition in dual energy with a 50 cm FOV at very high temporal resolution. Also possible is reconstruction in spectral imaging of monochromatic images with 101 different levels of specific energy, from 40 keV to 140 keV. Spectral imaging also allows the reduction of beam hardening and metal artefacts and optimization of the contrast/noise ratio.

Philips
Philips expanded its Brilliance iCT platform scanner family by adding the new Brilliance iCT SP (scalable platform). The new SP platform joins the Brilliance iCT 256-slice scanner and consists in a 128-slice upgradable scanner, i.e. if needed the number of slices can be doubled. The SP system has a gantry rotation time of 0.27 s and an X-ray tube power of 120 kV, i.e. the same as the 256 platform. The Nano-Panel 3D Spherical detectors permit large volume coverage while the Eclipse Dose Right Collimator technology focuses on low dose. Focal spot X-ray tube technology improves sampling density for greater spatial resolution. The Brilliance iCT SP system delivers as many clinical benefits as the 256 flagship model and can be situated in a room of 365 square feet.
In terms of software, Philips highlighted new applications, including automatic whole body bone removal for advanced vessel analysis, advanced brain perfusion and “perspective filet view” for virtual colonoscopy. Philips has also met the need for thin-client based software by adding to its CT workflow solution, Brilliance Everywhere, a thin-client-based information management system.
The new hardware and software configurations presented by Philips make this system scalable and upgradable depending on the local needs.

Siemens
Siemens presented the new Somatom Definition Flash Dual Source CT scanner, which represents a significant improvement since the introduction in 2005 of dual-source technology. The new Definition Flash is equipped with two 4-cm detectors that each acquire 128 slices of image data. Gantry rotation has further been decreased to 0.28 s, which translates into a temporal resolution of 75 ms. X-ray tube power has been increased to 2 x 100 kW, which facilitates the scanning of obese patients.
With the dual-source scanner, it is possible to achieve gapless z-sampling even with a pitch above 3; in fact, the two detectors create complementary data spirals that, when put together, include all the information generally found in a single spiral.
All these technical innovations allow scanning the entire thorax in 0.6 s, performing a 120 cm (whole body) scan in 3 s, and imaging the heart and coronary arteries in 250-300 ms.
Extremely important is the significant reduction of X-ray dose to the patient. For example, the heart and coronary arteries can be scanned with a radiation dose less than 1 mSv, as a consequence of several systems to reduce and control the dose.
Finally, single-dose dual-energy has also become possible due to the presence of a new Selective Photon Shield that pre-filters high kilovolt X-rays removing low-energy photons. This improves energy separation and material differentiation by 80%, while also reducing the dose significantly. Dose can also be reduced by a new system called Organ-Sensitive Dose Protection, which blocks X-rays from the portion of the spiral that will not be used in image reconstruction.

Toshiba
Toshiba presented the first dynamic volume CT system in the world:  the Aquilion One Dynamic Volume CT, winner of the "Minnies 2008" Best New Radiology Device, is a real breakthrough in CT technology.  Equipped with the Evolution Gantry and Quantum V detector technology, this scanner features 320 ultrahigh-resolution detector rows (0.5 mm in width), boosting this system to  16-cm coverage  over  a single 0.35 s gantry rotation.  On-board is the 16-cm wide new Mega Cool V Tube and Hybrid Slip ring technology that converts heat from kinetic energy gantry rotation into electricity.
Toshiba’s  technological achievements  allow a major step forward in dynamic CT evaluation, providing larger volume dynamic data sets,  and therefore setting new standards in 4D evaluation.  A single organ can be studied in terms of perfusion in a single breath hold and a temporally uniform acquisition, while cardiac evaluation is achieved  with a single heart beat acquisition.  Whole-brain perfusion studies can be viewed over the precontrast, arterial, and venous phases and the data can also be displayed for the first time as whole-brain CT digital subtraction angiograms.
One of the main focuses in the development of the Aquilion One has been dose and contrast medium reduction, allowing one to image a patient with a 50-cc contrast injection and a 5 mSv radiation dose.
In terms of software, different innovations were presented, focusing on dose reduction (variable helical pitch, cardio perspective, exposure,exposure pediatric, start demo), automated workflow (colon, cardio, cardio scoring, perfusion, pulmo) and clinical applications (fluoro, subtraction, plaque, phasexact).  The ConExact algorithm was also introduced as a new reconstruction software to manage the larger cone angle of the Aquilion One.
The new Aquilion One makes feasible the evaluation of dynamic motion and perfusion of anatomical structures in ways that were not previously possible, setting new standards in dynamic CT and presenting new challenges for the future.
 

Meta-analysis of prophylatic agents for CIN

Low- or iso-osmolar contrast agents and hydration protocols lower, but do not eliminate, the risk of contrast-induced nephropathy (CIN).  Thus, with the aim of further reducing this risk, several drugs have been tested for prophylactic action.  Researchers from Michigan did a meta-analysis of randomized controlled trials (RCTs) on the efficacy of CIN-protective drugs when iodinated contrast agents were administered intravenously [1].  They searched multiple bibliographic databases for studies published in English, French, German, Spanish or Italian.
The meta-analysis included 41 RCTs (6379 patients), published between 1994 and November 2006. Of these, 34 trials included patients with impaired renal function and no study excluded persons with diabetes; all but one trial involved cardiac catheterization. The most commonly tested agent was N-acetylcysteine (26 studies); theophylline was tested in 6 trials, dopamine, fenoldapam and furosemide were each studied twice, and single trials evaluated simvastatin, bicarbonate, mannitol, ascorbic acid and iloprost.  The meta-analysis found that N-acetylcysteine significantly reduced the incidence of CIN, with a relative risk (RR) of 0.62;  theophylline also reduced the risk (RR=0.49) but the results were not significant.  Single studies showed that ascorbic acid and bicarbonate were also protective.  Furosemide, instead, increased the risk, although the data did not reach significance.
Considering the low cost and high safety profile of N-acetylcysteine, the authors encourage its use in high-risk patients.  Nonetheless, they note that additional studies are required to determine the best prophylactic regimen. 

References

1. Kelly AM, Bwamena B., Cronin P. et al. Meta-analysis: effectiveness of drugs for preventing contrast-induced nephropathy. Ann Intern Med 148:284-294
   

ACR Appropriateness Criteria: updated version online

Over the past 15 years, the American College of Radiology (ACR) has produced a series of evidence-based guidelines with the aim of promoting high-quality radiology within the context of cost-effective healthcare.  The guidelines, called ACR Appropriateness Criteria, assist radiologists, referring physicians and patients in decisions on diagnostic imaging and radiological therapies. 
The ACR Appropriateness Criteria are organized into ten diagnostic categories (cardiac, gastrointestinal,  musculoskeletal, neurologic, pediatric, thoracic, urologic, vascular, women, women's breast) and eight therapeutic categories (interventional and oncological:  bone, brain, breast, Hodgkin's, lung, prostate, rectal-anal).  Overall, 160 guidelines are available, but each deals with several pathological variants, for a total of 700 clinical conditions considered.  Each guideline  contains of a series of tables indicating, for each condition, the recommended radiological procedures, their ratings determined by an expert panel (from 1 to 9, where 9 is the most appropriate), and the relative radiation level (scored in 5 categories). Each document also offers a  literature review. 
Unique feature of the ACR Appropriateness Criteria is their adherence to the Institute of Medicine's seven “attributes” for acceptable guidelines:  validity, reliability/reproducibility, clinical applicability, clarity, multidisciplinary process, scheduled review and documentation.  In fact, the guidelines are systematically updated (the latest release is dated October 2008), and new topics are added when epidemiological or technical factors require. The guidelines are freely available at the ACR website (www.acr.org) in the section “Quality and Patient Safety”.



 

Selected literature update: MDCT techniques for head and neck

Two methodological papers regarding head and neck imaging have been included in the full text literature library of MDCT.net.  The papers were published last month in European Radiology and  the International Journal of Cardiovascular Imaging.
In the first study [1], German and Slovenian researchers evaluated the reproducibility of functional 16-slice CT imaging of squamous cell carcinoma of the head and neck. They measured perfusion in tumor, before and after radiotherapy, and in nearby muscle tissue using dynamic contrast-enhanced CT, and determined the repeatability and levels of inter- and intraobserver agreement; these data are necessary for setting limits beyond which a therapeutic response may be defined.   
The second paper, contributed by researchers in Rotterdam [2], assessed the reproducibility of noninvasive measurements of carotid artery plaque from contrast-enhanced 16-slice CT angiograms.  Total volume and volumes of plaque components were measured using a plug-in called “Polymeasure”, created by one of the authors for the open source program ImageJ (http://rsb.info.nih.gov/ij). Interobserver variability was moderate, but improved when the three readers came to a consensus regarding the lesions' boundaries. The authors expect that software improvements will increase the reproducibility of this analysis, which may one day permit the assessment of stroke risk from MDCT angiographic findings.



References

1. Bisdas S., Surlan-Popovic K., Didanovic V., Vogl TJ (2008) Functional CT of squamous cell carcinoma in the head and neck: repeatability of tumor and muscle quantitative measurements, inter- and intra-observer agreement. Eur Radiol 18(10):2241-2250
   
2. de Weert TT, de Monyé C., Meijering E. et al. (2008) Assessment of atherosclerotic carotid plaque volume with multidetector computed tomography angiography . Int J Cardiovasc Imaging 24(7):751-759
   

Profile: European Society of Urogenital Radiology

Advancing knowledge in urogenital medicine and, particularly, in the use of imaging technologies for diagnosis and intervention in kidney, urinary tract and genital pathology is the mission of the European Society of Urogenital Radiology (ESUR). This medical society was founded in the early 1990s in Copenhagen by Henrik S. Thomsen, Ludovico Dalla Palma and other European radiologists who organized a series of symposia on uroradiology.
What is striking to the visitor of the esur.org website is the recent content (much of which is freely available) documenting the association's activities.  Persons interested in the association can read the twice-yearly newsletter and browse the abstract volumes of past annual meetings.  Also freely available is a 36-page publication reporting the ESUR's guidelines on the use of contrast medium; first drafted in 1996, the document is in its sixth revised edition (2007). The issue of safety in contrast-enhanced imaging is a major focus of the association, as shown by its book Contrast Media: Safety Issues and ESUR Guidelines, edited by H.S. Thomsen and J.A.W. Webb and published by Springer; the second edition is expected in February 2009. 

ESCR 2008 – A growing European meeting in cardiology

This year's annual meeting of the European Society of Cardiac Radiology (ESCR) was held in Porto, the second largest city of Portugal after Lisbon. Porto is an historical city, and the city's center has been declared a World Heritage Site by UNESCO.
ESCR meetings have had an increasing participation by radiologists and also some cardiologists, and are organized by the main experts in the field of cardiac CT and MRI.  This year, 600 participants attended the 3 day-congress covering the current indications for CT and MRI in the cardiovascular field.  The fact that many young European radiologists attended the meeting illustrates the high level of interest and potential of this emerging field of radiology. In fact, cardiac radiology has become a full sub-specialty of radiology, and a large number of examinations are expected to be performed by radiologists in the near future.
A large part of this congress was dedicated to education, with sessions on the basics of cardiac CT and MRI as well as those on state-of-the-art imaging protocols. Overall, 10 educational sessions were organized, including 8 parallel paper sessions and 2 “meet the experts” sessions.  Various symposia from CT and contrast medium manufacturers were also organized. In addition, more than 200 posters were available electronically. This resulted in rich content provided by specialists from all over Europe. This year, the importance of myocardial imaging was stressed in 6 sessions: myocardial perfusion, myocardial perfusion and infarction, imaging of cardiomyopathies, imaging of myocardial infarction, right heart disease and congenital heart disease.
In summary, ESCR is becoming an important European meeting that successfully mixes scientific and educational content in the field of noninvasive cardiovascular imaging.

Expert statement on noninvasive coronary artery imaging

Major progress has been made during the past decade in the noninvasive imaging of the coronary artery system using both magnetic resonance (MR) angiography and multidetector CT angiography. The advantages and limitations of these techniques and their expected future applications have been summarized in a “scientific statement” of the American Heart Association, recently published in Circulation [1]. 
The report contains the findings of a systematic review of the English language literature (1990-2006) indexed in PubMed. For each technique, the authors summarized technical aspects (e.g. imaging protocols, resolution, contrast enhancement) and clinical applications, including assessment of anomalous coronary arteries, coronary artery aneurysms and stenoses, and bypass grafts. Values of sensitivity and specificity in the detection of stenosis and bypass graft occlusion, reported in the literature, are tabulated for comparison. Limitations inherent to both of these purely diagnostic techniques, as well as those specific to one imaging modality, are presented briefly. Expert recommendations are provided on how coronary angiography results should be reported, and the possibility of detecting noncalcified plaques with noninvasive imaging is also discussed. 
The authors concluded with six recommendations, herein briefly summarized: patients without signs or symptoms of coronary artery disease should not undergo MR or MDCT angiography; symptomatic patients should undergo either MR or MDCT angiography depending on the presence of calcification or stenosis; anomalous coronary artery can be assessed with either technique, although MR angiography is preferred; reports of imaging examinations should indicate in detail the technique used, all cardiac and noncardiac findings, and any inadequacies of the procedure; multicenter and multivendor trials are needed to further validate current knowledge; and additional research is necessary to determine if these imaging techniques can accurately assess plaque. 


References

1. Bluemke DA, Achenbach S., Budoff M. et al. Noninvasive coronary artery imaging. Magnetic resonance angiography and multidetector computed tomography. A scientific statement from the American Heart Association Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention, and the Councils on Clinical Cardiology and Cardiovascular Disease in the Young. Circulation. 2008 Jul;118:586-606.
   

Dutch multicenter trial of a cardiac imaging algorithm for high-risk patients

Arterial disease of the lower extremities (peripheral arterial disease, PAD) is associated with increased risk of cardiovascular morbidity and mortality.  Dutch clinicians hypothesized that, in patients with PAD but without cardiac symptoms, noninvasive screening for heart disease followed by treatment (when necessary) would reduce the rate of cardiac events.  This hypothesis is being tested in an ongoing randomized controlled trial at four institutes in the Netherlands. The study design and rationale have been recently published [1] in Trials, a journal dedicated to the procedures, performance and reporting of clinical trials.
In the trial, patients assigned to the control group undergo coronary calcium scoring only. Patients randomized to the experimental group are screened according to a cardiac imaging algorithm. Briefly, after coronary calcium scoring, contrast-enhanced MDCT angiography (16 detector rows or more) is used to search for coronary artery stenosis, while MRI stress testing is used to screen for ischemia; patients with positive findings are referred for further testing and treatment. All patients are followed for 5 years to determine if the imaging algorithm, combined with appropriate treatment, reduces the rate of cardiovascular events.
The trial is registered at ClinicalTrials.gov with the identifier NCT00189111. A total of 1200 patients is necessary to demonstrate a 24% reduction in cardiovascular events. The trial began recruiting patients in 2005 and will conclude in 2012.



References

1. de Vos AM, Rutten A., van de Zaag-Loonen H. Non-invasive cardiac assessment in high risk patients (The GROUND study): rationale, objectives and design of a multi-center randomized controlled clinical trial. Trials. 2008 Aug; 9:49
   

Selected literature update: Pediatric CT radiation dose in Switzerland

Pediatric CT safety became a key topic of 2008 with the launch of the Image Gently campaign (see previous news from July 2008 ). In the interest of standardizing radiation dose settings on CT scanners, Image Gently recently held its first summit with vendors and healthcare providers. But to minimize radiation dose, scanning parameters must be optimized, i.e. through the establishment of diagnostic reference levels (DRLs). This was the scope of a recent paper in European Radiology.
Verdun and colleagues, working in Lausanne, Switzerland, surveyed the scanning practices of  pediatric CT centers nation-wide. Limiting the analysis to children 15 years of age or younger, the eight responding centers performed over 3500 CT examinations in 2005. Almost two-thirds of these examinations were of the brain, while the remainder involved  the chest or abdomen. One-third of all examinations were done on a single-slice scanner while two-thirds used multislice CT (8, 16 or 64 detector rows). 
Radiation dose ranged widely among centers for specific applications and age classes. For example, there was a 6.9-fold variation in dose-length product for brain examinations in 10- to 15-year-olds and a 51.4-fold variation in CT dose index for chest examinations in 1- to 5-year-olds. Mean scanning parameters were used to calculate DRLs for four age groups (<1, 1-5, 5-10 and 10-15 years); these were compared to those recently reported from the UK and Germany. 
The authors acknowledge that their recommendations are preliminary and will be revised on the basis of larger surveys. Despite an unusual organization (most results are presented in the Discussion) and a confusing or incorrect representation of data from Tables 4 and 5 in Figure 1, this paper is a important contribution to the development of radiation safety standards in pediatric healthcare.


References

1. Verdun FR, Gutierrez D., Vadar JP et al.  CT radiation dose in children: a survey to establish age-based diagnostic reference levels in Switzerland . Eur Radiol.  2008; 18:1980-1986.
   

Focus on skeletal science and imaging

The study of the skeleton and its pathologies is an interdisciplinary field involving radiologists, pathologists, orthopedic surgeons and rheumatologists. Skeletal researchers and physicians from these fields can meet in the International Skeletal Society (ISS), founded in 1974 and now with 500 members from 40 countries.
Major activities of ISS are organizing an annual meeting and producing the journal Skeletal Radiology. This year's meeting, which will be held in New Delhi from 29 October to 1 November, will include refresher courses in radiology and pathology; next year's meeting is planned for Washington DC. The society's official journal, Skeletal Radiology, is published monthly by Springer-Verlag. Edited by D.I. Rosenthal, M. Sundaram and J. Hodler, this journal deals with pathologies of the musculoskeletal system, emphasizing radiological aspects but also taking an interdisciplinary approach and publishing on anatomical, pathological, physiological, clinical, metabolic and epidemiological issues of the skeleton. Articles about multidetector CT published in Skeletal Radiology are included in MDCT.net's selected literature database.

Society profile: European Society of Thoracic Imaging

The European Society of Thoracic Imaging (ESTI, www.esti-society.org) was established in 1993 by a group of chest radiologists, led by the founding president Robert Dondelinger. The main activities of ESTI regard the annual meeting, held each June in a different European city. The meetings are focused on technical advances in imaging and state-of-the-art knowledge of chest diseases, including focal and diffuse airway diseases, diffuse infiltrative lung diseases, chest malignancies, and thromboembolic diseases of the pulmonary arteries. More recently, the society has focused attention on functional imaging of the lung and heart. 
ESTI is a member of European Society of Radiology and, through its interest in chest diseases, has ties with the Fleischner Society. ESTI, the Fleischner Society and three other societies from Asia and America organized a world congress on thoracic imaging in 2005, in Florence, Italy. A second world congress will be held in Valencia, Spain, city of the current president José Vilar, from 30 May to 2 June 2009. The conference program and call for papers are already available at www.2wcti.org.

Selected literature update: consensus paper on coronary artery calcium screening

A joint writing committee, formed by members of the European Society of Cardiac Radiology and the North American Society for Cardiovascular Imaging, recently produced a consensus paper on the methods and applications of coronary artery calcium (CAC) screening. The 26-page paper was simultaneously published in European Radiology and International Journal of Cardiovascular Imaging [1] and has been selected for inclusion in the full text literature database of MDCT.net.
In the paper, the authors summarized and compared current recommendations regarding CAC and discussed the interpretation of CAC scores. In particular, they analyzed the use of CAC scores as indicators of luminal stenosis and atherosclerotic plaques, and as predictors of cardiovascular events. They reviewed how CAC scores should be interpreted according to race, age and the presence of comorbidities such as diabetes mellitus and renal failure. They pointed out the importance of a zero calcium score in asymptomatic and symptomatic patients, and discussed the clinical interpretation of changes in CAC scores over time. Finally, they emphasized the need for standardized imaging protocols and quantification algorithms to assess CAC using multidetector CT scanners.



References

1. Oudkerk M., Stillman AE, Halliburton SS et al. Coronary artery calcium screening: current status and recommendations from the European Society of Cardiac Radiology and North American Society for Cardiovascular Imaging. Int J Cardiovasc Imaging. 2008 Aug; 24:645-671.
   

Italian clinical trial of new approach to CIN prophylaxis

Overnight hydration therapy is the standard procedure for preventing contrast-induced nephropathy (CIN) in patients with impaired renal function. A new clinical trial will investigate if furosemide-induced diuresis together with saline hydration is comparable or superior to standard hydration treatment.
The open, randomized trial is led by Drs. Antonio L. Bartorelli and Giancarlo Marenzi of the Monzino Cardiology Center (University of Milan), whose ethics committee recently approved the study. Adults may be enrolled if they have an estimated glomerular filtration rate <60 ml/min and require contrast-enhanced cardiac catheterization or percutaneous coronary interventions.
In the trial, standard saline hydration (1 ml/kg · h) will begin 12 h prior to catheterization and will continue for >12 h afterwards. The experimental treatment will be provided by RenalGuard (PLC Systems, Franklin, MA, USA; www.plcmed.com); this automated device increases urine output with furosemide (0.5 mg/kg given 1 h prior to catheterization) and replaces the lost fluid with an matched volume of saline during the procedure and in the following 4 h.
The trial is registered at ClinicalTrials.gov with the identifier NCT00702728. It began recruiting patients in June 2008 and will be completed by December 2009.

ImPACT: assessing the performance of CT scanners

In the healthcare sector, evidence-based purchasing means the acquisition of medical devices and equipment on the basis of objective data regarding the utility, efficacy and safety of the products. The ImPACT group, from the Medical Physics Department of St. George's Hospital in London, performs objective evaluations of CT scanners and provides advice on the purchase of such equipment. The group takes its name from “imaging performance assessment of CT scanners”.
The ImPACT group carries out independent evaluations of CT scanners in terms of functionality (technical aspects, imaging performance and radiation exposure) and usability of the systems. The evaluations are done according to standardized testing procedures developed over 25 years. Outcomes of the tests are published as reports, which may be single-product evaluations, multiproduct comparisons, user assessments and technical papers, such as one on radiation dose in multislice CT. All reports are freely available from the website www.impactscan.org.

Society profile: International Cancer Imaging Society

Promoting education in the multidisciplinary management of malignancy is the scope of the International Cancer Imaging Society (ICIS), founded in 1998 by Janet Husband and Rodney Reznek. The Society is actively involved in organizing continuing education courses for radiologists and specialists in nuclear medicine, and in promoting clinical research in oncology. The Society publishes the online, subscription-only journal Cancer Imaging, indexed in Medline since 2005.
Regular membership in ICIS is open to everyone interested in oncological imaging, and members with particular experience and competence can become “fellows” of the Society. Fellows contribute to ICIS by serving as section editors of Cancer Imaging and by organizing the annual teaching course.
The Society will hold its eighth annual teaching course and meeting on 6-8 October 2008 in Bath, UK. This year's course focuses on the clinical role of imaging in oncology; key topics include PET-CT, colorectal metastasis in the liver, imaging prior to radiation therapy, and tumor ablation. There will be a poster session and hands-on workshops. More information about ICIS, its meetings and journal is available at www.icimagingsociety.org.uk.

Award-winning web search tool in radiology

Radiologysearch.net is a new online tool designed to improve searching for information about radiology in the web. The tool was launched at the 2007 meeting of the Radiological Society of North America, by Roland Talanow (MD, PhD) of the Department of Radiology at The Cleveland Clinic Foundation (Cleveland, USA). Radiologysearch.net permits searching for content from radiology journals, online radiology teaching files and images, news, books, societies, courses, vendors, products. Free to use and free of advertising, the search tool facilitates more specific searching by limiting results to “thousands of peer-reviewed radiological web sites and hundreds of radiology journals”.
Among the unique features of the search engine is the ability to limit a search to specific types of content, choosing from a drop-down menu. Searching for recent radiological news can be limited to one of 18 different radiology specialties. The home page provides direct access to websites of over 200 radiology journals and almost 200 radiology societies worldwide.
Radiologysearch.net was presented as a scientific electronic exhibit at the 2008 meeting of the American Roentgen Ray Society (ARRS) and won a certificate of merit.

Selected literature update: MDCT and gastrointestinal bleeding

Gastrointestinal (GI) bleeding is a significant cause of hospitalization and death, especially in the elderly. The diagnosis of GI bleeding often requires a multidisciplinary effort, due to the many etiologies and patterns of hemorrhage, the difficulty of accessing the GI tract, and the choice of examination [1]. Two papers recently inserted in the literature database of MDCT.net discuss new diagnostic approaches for GI bleeding.
Filippone and colleagues, from Chieti, Italy, focused on obscure GI bleeding, defined as “ recurrent bleeding for which no definite source has been identified by routine endoscopic and barium contraststudies” [2]. Their paper in Abdominal Imaging provides an overview of two techniques to investigate obscure GI bleeding in the small bowel. Wireless capsule endoscopy permits direct visualization of the mucosal walls, while MDCT enteroclysis also permits assessment of the lumen and extraintestinal anatomy. The authors summarized the etiology of obscure GI bleeding and reviewed the clinical applications and advantages of both technologies.
Jaeckle and colleagues, from Ulm, Germany, published in European Radiology a prospective study of 36 patients with clinical signs of acute GI bleeding or intraperitoneal hemorrhage [3]. The results obtained with contrast-enhanced biphasic MDCT were compared to those from endoscopy, interventional angiography or surgery. MDCT correctly identified the bleeding site in 24 of 26 patients with GI bleeding and in 9 of 10 with intraperitoneal hemorrhage; no false-positives were recorded. The authors concluded that MDCT is a fast and accurate method for locating the site of acute GI bleeding.

1. Laing CJ, Tobias T, Rosenblum DI et al. (2007) Acute gastrointestinal bleeding: emerging role of multidetector CT angiography and review of current imaging techniques. Radiographics 27:1055-1070.
   
2. Filippone A, Cianci R, Milano A et al. (2008) Obscure gastrointestinal bleeding and small bowel pathology: comparison between wireless capsule endoscopy and multidetector-row CT enteroclysis. Abdom Imaging 33:398-406
   
3. Jaeckle T, Stuber G, Hoffmann MHK et al. (2008) Detection and localization of acute upper and lower gastrointestinal (GI) bleeding with arterial phase multi-detector row helical CT. Eur Radiol 18:1406-1413
   

Meta-analysis of diagnostic capabilities of MDCT angiography

In patients treated for coronary artery stenosis, in-stent restenosis (ISR) remains a clinical problem, even when drug-eluting stents are used. The current standard for follow-up evaluation of these patients is invasive coronary angiography, which is costly and poses a risk of complications. No noninvasive test for ISR has been clearly demonstrated to be effective, although numerous studies have evaluated the diagnostic capabilities of MDCT.
To assess the evidence on the diagnostic performance of MDCT angiography as a noninvasive test for ISR, Vanhoenacker and colleagues from Aalst (Belgium) and Ann Arbor (USA) did a meta-analysis of the relevant literature [1], and recently published their findings in BMC Medical Imaging. The authors searched the English language literature (1998-2007) for trials in which patients underwent both coronary angiography and MDCT angiography after stent implantation. They included studies that used at least a 16 detector-row scanner.
The meta-analysis included 14 studies (from 2004-2007), which provided data on 1039 stents and 400 patients; 5 studies used a 64 detector-row scanner. There was substantial heterogeneity in the size and type of stent studied, leading to heterogeneous results. The greatest variability in data regarded the percentage of stents considered non-evaluable, which reached 46% in one study. When data were combined in meta-analysis, the pooled specificity was very good (91%), but the sensitivity was moderate (82%) and considered insufficient for clinical use. Moreover, the authors found that the positive and negative likelihood ratios (9.34 and 0.20) were also inadequate for a diagnostic test.
The authors concluded that, on the basis of the published evidence, MDCT angiography has insufficient sensitivity to be used as a noninvasive diagnostic test for ISR. However, considering the evolution in scanner technology and the increasing use of thinner, less dense stents, additional studies are warranted.

1. Vanhoenacker PK, Decramer I, Bladt O et al. Multidetector computed tomography angiography for assessment of in-stent restenosis: meta-analysis of diagnostic performance. BMC Med Imaging. 2008, 8:14
   

Image Gently: an initiative of the Alliance for Radiation Safety in Pediatric Imaging

In July 2007, a group of pediatricians and radiologists met in Cincinnati to discuss issues of radiation exposure to children during CT examinations. From this meeting, the Alliance for Radiation Safety in Pediatric Imaging was formed, as was their educational campaign "Image Gently" [1]. The campaign, launched in the first months of 2008, aims to increase awareness about the need to adapt – or "child-size" – CT protocols to children to reduce radiation exposure. Four key guidelines have been developed: reduce the amount of radiation used, scan only when necessary, scan only the indicated area, and scan only once.
The alliance was founded by four pediatric and radiological societies in the US, and now involves 12 other associations including, from outside North America, the Sociedad Latino Americana de Radiologia Pediatrica and the Asian-Oceanic Society for Paediatric Radiology. Mailings about the initiative were sent to 500 thousand members of the participating societies, and 1340 medical professionals have taken the pledge to image gently. Information about how to adhere to the campaign is available from the website www.imagegently.org, as are useful resources including guidance on developing pediatric CT protocols.

1. Goske MJ, Applegate KE, Boylan J et al. The Image Gently campaign: working together to change practice. AJR Am J Roentgenol. 2008; 190:273-274
   

Selected literature update: novel MDCT applications

This month's addition to MDCT.net's full-text library includes two studies highlighting novel clinical applications. The papers report interesting but preliminary techniques which require continued evaluation in future studies.
A brief report from the Catholic University of Korea, published in Rheumatology International [1], illustrated the use of three-dimensional MDCT to examine erosive bone lesions in the rheumatic wrist. Volume-rendered 3D CT of two arthritic hands showed multiple tiny erosions that were not seen with conventional radiography.
A report from Germany [2] tested the possibility of using semi-automatic volumetry on lymph node metastases. Automated volume assessment had previously been shown to be precise and reproducible for lung nodules but, as the authors noted, lymph node assessment is more difficult due to their irregular shape and their frequent vicinity to tissue of similar density. This study compared manual volume calculations to those done by the prototype software OncoTREAT, and found that the semi-automatic method was slightly faster than manual assessment and gave a smaller interobserver difference in mean volume.

1. Ju JH, Kang KY, Kim IJ et al. Application of three-dimensional computed tomography for the rheumatoid wrist. Rheum Int. 2008 Jun; 28:811-813
   
2. Fabel M, von Tengg-Kobligk H, Giesel FL et al. Semi-automated volumetric analysis of lymph node metastases in patients with malignant melanoma stage III/IV-A feasibility study. Eur Radiol. 2008 Jun; 18(6):1114-1122
   

Practical CT colonography workshop

The ninth Hands-on Workshop on CT-Colonography will be held this September at the Forum des Deutschen Beamtenbundes in Berlin. Organized by Dr. Patrik Rogalla of Charité Hospital and the European Society of Gastrointestinal and Abdominal Radiology, the workshop will be led by 18 faculty from 7 European countries and Japan.
Key topics of this workshop on state-of-the-art CT colonography include fecal tagging, diagnosis of polyps and colorectal cancer, 2D and 3D viewing, image processing, and comparison with MR colonography. Participants will be able to try out several workstations and gain experience using each system's software. A detailed program is available online (http://www.esgar.org/index.php?pid=99&lang=1). The registration deadline is 18 August 2008.

CardioCTMR-2008: a new European course on noninvasive cardiac imaging

After 4 previous meetings in French language, in 2008 this new course turned into a European meeting, including simultaneous translation and the presence of speakers from different European countries. The scientific committee was composed of Dr. H.T. Abada (Iowa City), Dr. J. Bremerich (Basel), Prof. J. Bogaert (Leuven), Prof. B. Gerber (Brussels), and Prof. M. Oudkerk (Groningen). High quality lectures were given by internationally recognized speakers in a friendly atmosphere, during springtime in the center of Paris. In a beautiful art deco location, 300 participants listened to clinically oriented presentations about CT and MRI in cardiovascular diseases.
During the presentations, cardiac CT and MRI appeared most of the time as complementary techniques for cardiac and vascular imaging, rarely competitive. If anatomical information about coronary arteries is mainly provided by CT, functional assessment is until now the strong point of MRI. Cardiac myocardial contrast enhancement may be detected by both, even if late enhancement on MRI is still probably more reliable due to higher contrast with gadolinium.
The first part of the congress addressed technical points for both CT and MRI. After the manufacturers’ session, introducing the latest developments of GE, Philips, Siemens and Toshiba, 2 presentations addressed the benefits of a high temporal resolution and of a large z-coverage. The next presentations described the safety aspects of both CT (radiation dose and iodine injection) and MRI (including 3T imaging).
The second session in the afternoon focused on vessel imaging, with a large part dedicated to coronary vessels. A communication from Prof. Oudkerk extensively reviewed the value of calcium scoring for stratification of cardiac risk. State-of-the-art CT coronary angiography was presented by Dr. Küttner and Dr. Sablayrolles. Coronary plaque imaging was addressed by Dr. Leber. State-of-the-art MR coronary angiography, with its actual limitations, was detailed by Prof. Bogaert. The end of this session included a presentation by Dr. Huppertz on a new concept of whole body MR angiography with intravascular contrast agent, underlying new possibilities and improvements in diagnostic accuracy.
The last session concerned myocardium, valves and heart disease with a large part for discussion and questions from the audience. The new possibilities of CT for myocardial evaluation were stressed in balance with MRI by Prof. Gerber, probably one of the greatest experts in this field. Dr. Habis from Paris described the new possibilities of CT for valve imaging from his own experience and from a review of the recent literature. The complementarity of CT and MRI was evident after 2 lectures about congenital heart disease and the following discussion. The congress ended with selected cases and free communications.
In conclusion, this successful meeting was of high interest for radiologists and cardiologists specialized in this field. The next congress will be held in the same location, on 11-12 June 2009. More information is available at http://www.diagest.com/cardioctmr.

Post-graduate course of ESGAR: European Society for Gastrointestinal and Abdominal Radiology

The 19th annual meeting and post-graduate course of the European Society for Gastrointestinal and Abdominal Radiology (ESGAR, www.esgar.org) took place in Istanbul, Turkey, from 10 to 13 June 2008. More than 1200 participants from over 50 countries attended the meeting, making it one of the most successful in the history of ESGAR. The main topic of this year's postgraduate course was MDCT of the abdomen. The congress presidents, Profs. Akhan and Elmas, stated that the "amazing advances of MDCT technology and its applications demanded that a meeting be devoted to this exciting issue". Key issues of abdominal MDCT were reviewed and summarized by internationally renown speakers. In-depth discussions about the role of MDCT and its promising applications in the daily practice of abdominal radiology were expected - and the high expectations of the course's participants were well met by the faculty of speakers. The course was aimed at both radiologists in-training and sub-specialists and experts in the field, and all relevant topics of ESGAR's subspecialties were covered, which worked out very well. The four sessions of the abdominal MDCT course (each 90 minutes in length) were entitled "All you need to know", "Added value in hepatic, pancreatic and biliary imaging", "Gastrointestinal tract imaging: evolution or revolution?" and "Abdominal vascular imaging: a success story". In the first session, relevant background information regarding the development of MDCT from 4x to 320x detector configurations and its implications was provided, followed by an excellent lecture dealing with dose issues in MDCT, of which we all have to be aware. Additional lectures discussed potential benefits of dual energy imaging, perfusion imaging, and hybrid PET-MDCT. In the liver talks, emphasis was put on both the value of MDCT in the detection and characterization of incidental liver lesions in the non-cirrhotic liver and the significance of MDCT in the surveillance of the cirrhotic liver. In addition, the added value of MDCT over spiral CT and other non-invasive modalities in the evaluation of biliary malignancies was discussed. Of course, the tremendous value of MDCT in the detection and evaluation of pancreatic carcinoma was also presented and discussed, including protocols for pre-operative assessment of pancreatic carcinomas, and the role of MDCT versus state-of-the-art MRI in this context. The title-question "Gastrointestinal tract imaging: evolution or revolution?" was definitely answered with "Both: evolution and revolution!" The lectures not only focused on CT colonography, but also provided excellent insight into protocols for the MDCT assessment of the esophagus, stomach, duodenum and smal bowel. An additional emphasis was put on the value of computer-aided detection for CT colonography. Regarding abdominal vascular MDCT imaging, the specific contrast protocols for these indications including contrast injection, timing and image reconstruction strategies were introduced. After this introduction, three lectures focused on the fantastic possibilities and genuine value of MDCT in the clinical settings of hemorrhage, thrombosis and liver transplantation. Overall, this one-day post-graduate course was very well perceived by the participants. It can only be hoped that it will be repeated in a similar form in future meetings. In addition to the post-graduate course, MDCT was an important topic in many scientific presentations, workshops and lunch sessions of the main meeting. Congratulations to ESGAR for this successful, interesting and highly educational meeting!

Effectiveness of MDCT angiography: a systematic review from the UK Health Technology Assessment programme

Researchers from Aberdeen reviewed the literature for evidence on the clinical and cost effectiveness of MDCT angiography, as alternative to invasive coronary angiography, in diagnosing coronary artery disease (CAD). The 180-page systematic review [1] was recently published in the monograph series Health Technology Assessment, produced by the Health Technology Assessment (HTA) programme in the UK.
The authors searched the English-language literature (from 2002-2006) for diagnostic and prognostic studies that compared 64-slice (or higher) CT angiography to coronary angiography. Data from 21 articles and 24 abstracts were analyzed.& When data were pooled (from 13 studies), 64-slice CT angiography was found to have high sensitivity (median, 99%) and negative predictive value (100%) and only rarely were CT images not evaluable. Sensitivity and specificity were also determined for individual cardiovascular segments and for the analysis of bypass grafts and stents.
From this analysis, the authors concluded that 64-slice CT is "almost as good as coronary angiography in detecting true positives." However, a lower specificity in certain segments may provide false-positive diagnoses so, they warn, coronary angiography remains necessary to confirm pathological findings. Although no study specifically assessed the costs of 64-slice CT angiography for CAD, the authors noted that, in persons in whom CT has ruled out CAD, avoidance of coronary angiography will result in notable savings.
The monograph ends with recommendations for both practice and continued research. Clinically, the authors see the main advantage of 64-slice CT angiography as that of ruling out CAD in symptomatic persons. Regarding future research, they call for high-quality studies on the advantages and costs of 256-slice CT angiography, including the ability of MDCT to characterize plaques.

1. Mowatt G., Cummins E., Waugh N. et al. (2008) Systematic review of the clinical effectiveness and cost-effectiveness of 64-slice or higher computed tomography angiography as an alternative to invasive coronary angiography in the investigation of coronary artery disease. Health Technol Assess 12(17):1–164
   

Selected literature update: gynecological applications of MDCT

Recently selected for full-text inclusion in MDCT.net are two articles from European Radiology that describe the use of 16-row contrast-enhanced CT in staging endometrial carcinoma [1] and differentiating adnexal masses [2]. These "back to back" publications were authored by Tsili and coworkers from the University of Ioannina, in mainland Greece.
In the first study, the researchers tested the effectiveness of MDCT in assessing the depth of myometrial invasion and the presence of cervical infiltration. The prospective study, prompted by the fact that single-row CT for this pathology has low accuracy, was carried out in 21 women with newly diagnosed endometrial carcinoma. Regarding myometrial invasion, MDCT had 100% sensitivity, 80% specificity and 95% accuracy (compared with histological analysis on surgical specimens), and thus was considered equivalent to MRI. For cervical involvement, sensitivity and accuracy were lower (78% and 81%, respectively).
The second report compared the diagnostic performances of MDCT and MRI in 67 women with suspected ovarian masses. At surgery, 89 adnexal masses were found; histopathological analysis revealed that 23 of these were malignant. Both imaging techniques detected 85 of the 89 lesions. In identifying malignant lesions, MDCT had 90.5% sensitivity, 93.7% specificity, and 92.9% accuracy. MRI performed better but at receiver operating characteristic (ROC) analysis, this difference was not significant.
The authors note that their findings must be confirmed in larger, more heterogeneous series. They predict that MDCT will become a widely used method for characterizing ovarian masses due to its ease of use and wide availability.

1. Tsili AC, Tsampoulas C., Dalkalitsis N. et al. (2008) Local staging of endometrial carcinoma: role of multidetector CT. Eur Radiol 18(5):1043-1048
   
2. Tsili AC, Tsampoulas C., Argyropoulou M. et al. (2008) Comparative evaluation of multidetector CT and MR imaging in the differentiation of adnexal masses. Eur Radiol 18(5):1049-1057
   

Lung Imaging Database Consortium

In 2000, the Cancer Imaging Program (of the US National Cancer Institute) created the Lung Imaging Database Consortium (LIDC). Goals of the LIDC are to establish guidelines on spiral CT imaging of the lung, to populate a database of spiral CT images of the lungs, and to develop new algorithms for image searching and analysis. The LIDC was formed with the idea that the effectiveness of spiral CT screening for lung cancer in at-risk persons may be improved by advanced image processing methods.
Membership in LIDC is awarded to institutions who have received funding for research on computer-aided diagnosis (CAD) of lung nodules on thoracic MDCT. Currently, research teams from 5 US universities are members. Since its founding, the main focus of LIDC-sponsored research has been to resolve clinical and technical issues in nodule detection and image database design. The resulting database and its image analysis algorithms will be made available to the public and medical imaging community. More information on the methods and goals of the LIDC is available online at http://imaging.cancer.gov/programsandresources/InformationSystems/LIDC/page1; some first results have been published [1].

1. Meyer CR, Johnson TD, McLennan G. et al. (2006) Evaluation of lung MDCT nodule annotation across radiologists and methods. Acta Radiol 13(10):1254-1265
   

First coronary images from 320-detector row CT

The International Journal of Cardiovascular Imaging recently published an analysis of coronary images acquired by the new AquilionOne Dynamic Volume CT scanner (Toshiba, Tochigi-ken, Japan) [1]. The scanner, which was showcased at last year's meeting of the Radiological Society of North America, has been installed in only a few sites but will shortly become commercially available.
Researchers at Brigham and Women's Hospital, Boston, one of the AquilionOne test sites, worked with Toshiba America Medical Systems to assess the scanner's performance in whole cardiac coverage, single-beat coronary CT angiography. They studied 40 patients who received iopamidol (370 mg I/mL at 6 mL/s) prior to imaging with prospective (n=34) or retrospective (n=6) ECG gating. Two independent readers subjectively rated each patient's images at 15 coronary segments on a 4-point scale: 1, unevaluable; 2, acceptable despite artifacts; 3, good (minor artifacts); and 4, excellent (no artifact). Each reader thus scored 600 segments for image quality and contrast opacification.
Seventeen coronary segments were not characterizable for anatomical reasons, leaving 583 segments for study. Readers 1 and 2 gave an excellent image quality score to 88.7% and 89.9% of these segments, and a good-acceptable score to 11.1% and 9.9% of segments, respectively; only one segment was considered unevaluable by both readers. Contrast opacification was also excellent, with a mean score of 3.93 (out of 4.00) for all segments, but the percentage of segments with an excellent opacification score was not reported. The mean estimated radiation dose for all patients was 8.3 mSv (SD=3.4); it was significantly greater in patients with body mass index (BMI) >30 kg/m2 (vs. those with BMI<30) and in patients who had retrospective ECG gating (vs. prospective gating).
The authors attributed their successes to a "meticulous protocol" for controlling heart rate and to the high iodine load and injection rate. They acknowledged, however, that further study is necessary to define the threshold of temporal resolution that provides images without motion artifacts, and to assess the opacification achievable with smaller iodine doses. Finally, since the CT dose index method of calculating radiation exposure is not applicable with 320-row scanners, they estimated dose with a scaling factor. Thus, new methods of calculating radiation dose for wide-area CT scanners are required.

1. Rybicki FJ, Otero HJ, Steigner JL et al. (2008) Initial evaluation of coronary images from 320-detector row computed tomography. Int J Cardiovasc Imaging 24:535-546
   

Selected literature update: new tools for managing radiation dose

Included among the recently published articles selected for full-text inclusion in MDCT.net are two presentations of tools for reducing and estimating radiation dose.
In a technical note published in Radiation Medicine [1], Funama and colleagues from Kunamoto University, Hitachi Medical and Gate Tower Institute of Image Guided Therapy (all in Japan) described a noise-reduction filter designed to improve the quality of hepatic images acquired with low-dose CT. They claimed that, using the filter, radiation dose can be reduced by 50% without compromising on quality.
Deak and colleagues from the University of Erlangen-Nürnberg, the UK Health Protection Agency, and the German National Research Center for Environment and Health described a Monte Carlo tool to simulate the 3D distribution of radiation during multidetector CT [2]. In this phantom study, the researchers adapted an existing Monte Carlo algorithm to the lastest multidetector CT technology, incorporating information regarding scanner geometry and X-ray spectrum. Due to its modular nature, the new algorithm should be able to evolve with multidetector CT scanners.

1. Funama Y., Awai K., Miyazaki O. et al. (2008) Radiation dose reduction in hepatic multidetector computed tomography with a novel adaptive noise reduction filter . Radiat Med 26(3):171-177
   
2. Deak P., van Straten M., Schrimpton PC et al. (2008) Validation of a Monte Carlo tool for patient-specific dose simulations in multi-slice computed tomography. Eur Radiol 18(4):759-772
   

Italian Society of Medical Radiology: national meeting and press conference

The forty-third national congress of the Italian Society of Medical Radiology (SIRM) was held on 23-27 May 2008. The association, founded in 1913, holds a conference every two years. This years' meeting, held in Rome, welcomed 5000 radiologists and 1000 exhibitors and visitors. During the conference, Prof. A. Siani became President of SIRM, replacing Prof. R. Lagalla.
The principal themes of the meeting were outlined in a press conference on 22 May. The presentation of data from a nation-wide survey of radiology structures received the most press coverage in Italy. Another hot topic was the risk of ionizing radiation from diagnostic imaging, discussed by Prof. A. Giordano. Several important Italian studies were presented, including the multicenter NIMISCAD study on the use of multidetector CT in the diagnosis of coronary artery disease, and the IMPACT study on the use of virtual colonoscopy to diagnose colorectal neoplasia.
Other issues discussed at the press conference included the potentials of teleradiography (Prof. A. Siani), the difficulties in reducing waiting list times (Prof. P. Marano), and the future of echosonography (L. Solbiati). Finally, regarding the profession, Dr. S. Montemezzi reported on the underrepresentation of women radiologists in positions of power, and emphasized the need to train university women in leadership. Prof. A. Siani described the future figure of the radiologist: a specialist able to follow the technological evolution of the field, manage diagnoses, assess the outcomes of therapy and carry out radiological interventions as necessary.



by V. Matarese

National survey of diagnostic and neurological radiology structures in Italy

In occasion of the 43rd conference of the Italian Society of Medical Radiology (SIRM), preliminary data from a nation-wide survey of radiology structures were presented. The survey, organized by SIRM together with the Italian Association of Neuroradiology and the National Radiologists Union, aims to survey radiological equipment, information systems and personnel throughout the country. Completion of the survey, which should involve 950 public and 600 private structures, is expected to require 4 years.
At the SIRM conference, data were presented for 193 radiology units from Valle d'Aosta, Bolzano, Trento, Tuscany, the Marche and Sicily. Altogether, in these six regions and autonomous provinces, more than 2800 radiological instruments were recorded. Of these, 12% are CT scanners, 5% are MRI scanners, and 5% are for mammography. Overall, 23% of the instruments are older than 10 years and 56% are older than 5 years, the time when such technology is considered to become obsolete, noted Prof. Lagalla, President of SIRM.
Moreover, in these six surveyed geopolitical areas, over 8 million radiological examinations or interventions were performed in 2006, leading to an estimate of 40-50 million examinations yearly in all of Italy, a country with a population of just 59 million. Prof. Lagalla commented that this excessive number of requests for diagnostic radiology is having a major impact upon healthcare costs and waiting list times, is encouraging patients to turn to private structures that do not always have the best equipment, and is contributing to the population's exposure to ionizing radiation. In light of these consequences, SIRM is emphasizing the adherence to national guidelines regarding the prescription of radiological examinations and is also encouraging public education regarding the health effects of radiation exposure.



References

1. Il "parco radiologico" italiano invecchia. Corriere della Sera Salute, 23 May 2008
   

Stanford's International Symposium on Multidetector-Row CT

The 10th annual International Symposium on Multidetector-Row CT, organized by Stanford University's Department of Radiology, was held in Las Vegas, on 13-16 May 2008. As in previous years, the meeting was extremely successful with a large participation of radiologists from North America but few from Asia or Europe. The meeting was attended by approximately 1800 delegates who packed the room throughout the course.
The course, directed by Drs. Geoffrey Rubin and Gary Glazer of Stanford University, followed the format of previous editions, with speakers from Stanford and other institutions in the United States, Europe and Asia. Many representatives from different vendors were also present, and the large technical exhibition permitted course attendants to get the lastest news regarding producers of CT scanners, image-processing software, picture archiving and communications system (PACS) and contrast agents.
Starting at 7 a.m. and continuing until 6.30 p.m., the course offered a large number of lectures covering all aspects of MDCT, from technical innovations to clinical applications. For the first time this year, interactive sessions were also provided. In these 90-minute sessions focused on different CT applications, participants reviewed cases in pairs and then discussed them with experts.
The first day focused on technical innovations, especially dual-energy CT, contrast agent administration and the risks associated with its injection. It was emphasized that contrast-induced nephropathy is a rare condition that can be significantly reduced by correctly hydrating patients.
The abdominal sessions evaluated the advantages and limitations of CT and indicated if and when other examination are required. Particularly interesting are the potentials of dual-energy CT in abdominal applications. In fact, it may become possible to routinely use virtual nonenhanced images to quantify enhancement and help characterize lesions in abdominal organs, such the kidneys. Dual-energy CT may also help characterize renal stones and, therefore, improve the management of patients with urolithiasis.
The importance of image processing was also illustrated in many different applications. Three-dimensional CT acquisition may help overcome the limitations of bi-dimensional RECIST criteria in the follow-up of oncology patients, with the aid of precise volumetric measurements. In this setting, the sixth annual workstation face-off was interesting in that it permitted comparison of how the major workstations can be used to visualize and analyze volumetric MDCT data. A set of vascular, cardiac, colon and lung cases were provided to users of ten different workstations; these users were asked to demonstrate, in a few minutes, the capabilities and results of the workstations. All workstations provided excellent results, although only few had full capabilities in all anatomical fields. For instance, integration of different modalities, such as CT and PET in lung imaging, is provided by only a few vendors. The discussion stressed the fact that radiologists use tools that are readily available, possibly on a PACS, and prefer not to use different workstations for each option. This is particularly true for the analysis of lung images by computer-assisted detection (CAD), which few of the course faculty and participants use in routine practice.
In the vascular sessions, the role of CT angiography was well documented, with all established clinical applications and several new fields, such as the assessment, in combination with PET, of atherosclerotic plaque, and imaging of the entire vasculature with whole-body protocols of acquisition and administration of contrast agent.
Apart from the scientific sessions, the meeting offered several social events in the lively atmosphere of Las Vegas.



by C. Catalano

Getting up to date in radiology – in the Mediterranean

With the approaching warm weather, radiologists have several opportunities to combine continuing education and a visit to the Mediterranean area, with two national conferences in Western Mediterranean countries and a "cruise course" to the Eastern Mediterranean.
The Italian Society of Medical Radiology (Società Italiana di Radiologia Medica) will hold its forty-third national congress in Rome, on 23-27 May. The congress will offer monothematic courses, round table discussions, radiology and informatics workshops, oral presentations and posters. The scientific program can be viewed online at www.congresso.sirm.org.
During the same days, in Seville, the Spanish Society of Medical Radiology (Sociedad Española de Radiologia Medica) will hold its twenty-ninth national congress. Each day of the conference will be divided into sessions of continuing education, updating, debate and practice workshops. Further information and the scientific program are available at www.seram2008.com.
Finally, the Johns Hopkins University School of Medicine is organizing a cruise course called "Advanced topics in multidetector CT scanning". Dubbed "MDCT at sea", this course will be held from 27 July to 3 August onboard the ship Navigator of the Seas (Royal Caribbean Cruise Lines). As participants sail along the coasts of Italy, Greece and Turkey, they will follow about 25 lectures on state of the art MDCT, with a focus on 64-slice scanning, given by E. Fishman and KM Horton (Baltimore), MP Federle (Pittsburg) and EA Zerhouni (Bethesda).
Further information is available at www.hopkinscme.net.

North American physicians rate vendors and their products

Vendors of healthcare software, services and equipment are rated twice yearly by a panel of North American physicians and hospital directors in the KLAS Top 20 Report (KLAS Enterprises, Orem, USA). Produced since 1998, this report ranks 750 products and services from 200 vendors. Top-rated vendors for each market segment are designated as "category leader" and, for the most important segments, as the "Best in KLAS".
Published in December 2007, the latest report identified the Toshiba Aquilion 64-slice CT scanner as Best in KLAS in the CT segment. All category leaders are listed at klasresearch.com.
The same firm also offers a report on 64-slice CT. Published in April 2007, the report is based on data from interviews with 130 CT users. The study compared four major scanners (GE LightSpeed VCT, Philips Brilliance, Siemens Somatom Sensation and Toshiba Aquilion) on issues of image quality, reliability, field of view and productivity for clinical applications of colonography, angiography, and head, chest, spine and whole body imaging.



by V. Matarese

Guidelines on screening and prevention of colorectal cancer: role of CT colonography

Three US medical associations recently combined forces to issue joint guidelines on screening for colorectal cancer (CRC). The consensus statement, published simultaneously this March in the journals Gastroenterology, Radiology, and CA: A Cancer Journal for Clinicians (1), was authored by 14 physicians representing the American College of Radiology, the American Cancer Society, and the Multi-Society Task Force on Colorectal Cancer.
In Europe, CRC is the second most common neoplasm and the second most important cause of cancer-related death in men and women (2). In screening for CRC, the primary goal has been to reduce mortality by early detection. However, since some screening methods also identify adenomatous polyps, considered "nonobligate precursor lesions", a second goal can be cancer prevention by polpectomy.
In this context, the authors document the effectiveness of various screening options for asymptomatic adults at normal risk, with the aim to help physicians and patients make informed decisions. Screening options considered in the report are divided technologically into stool tests and so-called structural exams, including endoscopic and diagnostic imaging approaches. Stool tests are effective in identifying CRC but not premalignant adenomatous polyps, while structural examinations identify both cancer and premalignant polyps.
The report summarizes evidence for the efficacy, benefits and risks of three stool tests and four structural examinations (e.g. flexible sigmoidoscopy, colonoscopy, double-contrast barium enema and CT colonoscopy). Regarding CT colonoscopy, the authors state that, on the basis of recent evidence, this method "is comparable to [optical colonoscopy] for the detection of cancer and polyps of significant size when state-of-the-art techniques are applied" and therefore is an "acceptable option for CRC screening".
The authors recommend that patients be informed of the choice of screening options and the associated risks and benefits. They encourage the use of screening tests that detect both polyps and cancer, and argue that cancer prevention should become the main purpose of CRC screening.

1. Levin B., Lieberman DA, McFarland B. et al. (2008) Screening and Surveillance for the Early Detection of Colorectal Cancer and Adenomatous Polyps, 2008: A Joint Guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. CA Cancer J Clin Mar 5; [Epub ahead of print]
   
2. Ferlay J., Autier P., Boniol M. et al. (2007) Estimates of the cancer incidence and mortality in Europe in 2006. Ann Oncol 18:581-592
   

Best practices in recording and reporting radiation dose

A new report entitled "The measurement, reporting, and management of radiation dose in CT" [1] has been issued by the American Association of Physicists in Medicine (AAPM). With this report, AAPM aims to provide expert guidance to institutions and individual radiologists on how to understand and manage radiation from CT.
The 34-page technical report begins with an overview of multidetector CT technology, and then defines and discusses parameters for assessing CT radiation dose, in particular the computed tomography dose index (CTDI), the dose-length product and the effective dose. The document also reviews methods for reducing radiation exposure, by modifying technical parameters (e.g. X-ray beam filtration or collimation, tube current modulation), adapting scanning parameters to a patient's size and weight, and using automatic exposure control and noise-reduction algorithms. It concludes by commenting on the clinical use of CTDI and other dose parameters.
Founded 50 years ago, AAPM is a nonprofit scientific, educational and professional organization that promotes the application of physics to the diagnosis and treatment of human disease, by supporting research and by disseminating scientific and technical information.

1. American Association of Physicists in Medicine (AAPM) (2008) The measurement, reporting, and management of radiation dose in CT. Report of AAPM Task Group 23 of the Diagnostic Imaging Council CT Committee. AAPM, College Park (report no. 96)
   

UK advisory board statement on personally initiated CT examinations

Some asymptomatic individuals request CT examinations at private clinics to abate anxiety about health due to a particular fear of or "emotional connection" to a disease. This fact and the commercial availability of CT services have led the Committee on Medical Aspects of Radiation in the Environment (COMARE) to issue a report entitled "The impact of personally initiated X-ray computed tomography scanning for the health assessment of asymptomatic individuals." COMARE is an independent expert committee that advises the UK government on all aspects of radiation.
Although the extent of personally initiated CT examinations is unknown, the report noted that more than 90% of all examinations in the UK are done within the National Health Service, but this leaves almost 10% of examinations in the private sector. Commercial examinations are becoming more frequent, as they are marketed as a form of preventative healthcare. The current offer regards whole body scanning as well as imaging of the lung, heart and colon.
In this context, COMARE assessed the evidence for benefits and detriments of CT examinations of asymptomatic individuals, outside of population screening programs. This evidence is summarized in an 83-page document, which ends with 9 recommendations. In particular, COMARE recommended that information from commercial CT services be fully integrated into public "pathways" of healthcare and that symptomatic individuals who request a commercial CT examination be instead referred to a general practitioner. While CT of the colon and heart may be beneficial in some asymptomatic individuals, the authors found no evidence of a benefit from lung imaging in individuals. Finally, COMARE strongly recommended against whole body CT screening of asymptomatic individuals because of the impossibility of optimizing exposure parameters.



References

1. Committee on Medical Aspects of Radiation in the Environment (COMARE) (2007) Twelfth Report. The impact of personally initiated X-ray computed tomography scanning for the health assessment of asymptomatic individuals. Health Protection Agency, Oxon

European Congress of Radiology 2008

The annual European Congress of Radiology (ECR) was recently held in Vienna, on 7-11 March 2008. Forty years after the first European conference, the ECR has developed into a truly international event with almost 18 000 visitors this year from 95 countries. A 20% increase in abstract submissions testifies to the scientific importance of this conference, and the fact that only one-third of submitted abstracts was accepted is evidence of its selectivity. In the following news items, MDCT.net's board members report on what they found to be the most interesting aspects of the conference.

ECR 2008 sessions on gastrointestinal and abdominal imaging

At ECR 2008, different aspects of MDCT in the abdominal-gastrointestinal context were discussed both in the categorical course "Multidetector CT made easy” and in several scientific sessions. The categorical course was organized in eight 1.5-h sessions, two of which were dedicated to abdominal and gastrointestinal imaging.
In the talk “The liver: is MDCT beating MRI?”, R.C. Nelson from Durham, USA, pointed out that although it has long been recognized that the inherent tissue contrast between liver parenchyma and liver tumors is greater for magnetic resonance imaging (MRI) than for CT, this has not necessarily thrust MRI ahead of CT in clinical practice. In general, contrast-enhanced imaging with either iodine (CT) or gadolinium (MRI) yields similar enhancement patterns and thus comparable sensitivities. Still, MR cholangiography has an advantage over CT in the evaluation of the biliary tree and, furthermore, some liver-specific gadolinium-based contrast agents have delayed biliary excretion, which can be helpful for characterizing certain tumors.
While this talk emphasized that MRI may still have advantages over MDCT in terms of liver imaging, M. Zins from Paris, France, in the talk “The pancreas: MDCT stays the number one”, claimed that MDCT is the standard of reference for the assessment of most pancreatic diseases. These include pancreatic cancer, endocrine and cystic tumors, and acute and chronic pancreatitis. Zins admitted, though, that MRI is a strong competitor in terms of evaluation of biliary and pancreatic ducts and (again) that MRI is especially useful for the evaluation of associated liver disease. However, the improved spatial resolution of MDCT with MIP reconstruction allows the best evaluation of resectability in patients with pancreatic cancer.
Regarding the kidneys and the excretory system, F. Stacul from Trieste, Italy, discussed the problem of radiation exposure when substituting intravenous urography (IVU) with MDCT. MDCT allows the acquisition of urographic images comparable to those obtained with IVU and thus can replace IVU in clinical situations in which imaging of the entire urinary system with detailed calyceal evaluation is required, e.g. asymptomatic hematuria, follow-up of transitional cell carcinoma, congenital anomalies, fistulas, tuberculosis, and planning of difficult endo-urological procedures. The best way to lower radiation exposure is through radiologists' awareness of it. MDCT urography has to be tailored to the clinical problem. While higher exposures may be justifiable in patients at high risk of neoplasms, this may not hold true in patients with a high probability of having benign disease. Such tailored approaches may result in MDCT urography cancelling the residual role of IVU.
P. Rogalla from Berlin, Germany, tackled the issue of small bowel MDCT in his presentation entitled “Small bowel CT: try it, you'll like it”. He distinguished three types of indications: general overview (non-specific examination), exclusion of neoplasia or inflammatory bowel disease (IBD), and suspected intestinal ischemia. Similar to the previous arguments regarding CT urography, he indicated that it is mandatory to tailor the MDCT imaging protocol to the predominant clinical question. He explained that both radiodense (positive) and radiolucent (negative) contrast agents are in use and that their individual characteristics may be advantageous diagnostically. If the arterial perfusion of the small bowel wall stays in the foreground (e.g. when imaging inflammatory diseases), negative contrast agents should be preferred, while for detection of tumors and fistulas, positive agents may be advantageous. He concluded that with optimized contrast filling of the entire small bowel, tumor detection and staging can be performed in a single CT examination.
J. Stoker from Amsterdam, Netherlands, continued on the topic of gastrointestinal imaging with the talk “Bowel emergencies: the basic tool”, and explained that MDCT has surpassed ultrasonography (US) in imaging of bowel emergencies in many situations due to high spatial resolution in a large field of view with vascular information. MDCT protocols include the use of intravenous contrast medium, while oral contrast medium is not routinely used in many institutions. Important imaging findings include abnormal air and fluid configurations, fat infiltration and vascular abnormalities (e.g. thrombosis). Apart from good test accuracy, MDCT is fast, and communication with clinicians and comparisons of repeat examinations are easier than with US.
Finally, A. Laghi from Latina, Italy, gave a talk entitled “Colon and rectum: not only colonography” and pointed out that, in current clinical practice, MDCT plays an important role in the study of the large bowel, but rigorous technique is mandatory in order to get optimal images. Air insufflation, even in an unprepared colon, may help to better define the length of colonic involvement and to assess the presence of a luminal stricture. Intravenous administration of contrast medium is also extremely useful in the analysis of parietal alterations, especially in inflammatory lesions. These represent clear indications for MDCT of the colon, in particular in defining unclear clinical findings (e.g. mild diverticulitis). Complications of inflammatory processes (abscesses) can be easily diagnosed and treated, if necessary. In cancer imaging, MDCT is extremely important in local as well as distant staging. In particular, in rectal cancer, high-resolution MDCT, using thin collimation with sub-millimeter resolution, is challenging MRI in the assessment of perirectal tumor spread as well as the involvement of the mesorectal fascia.
Then, in the scientific session “CT colonography”, 7 of 10 presentations focused on different aspects of computer-assisted detection (CAD), which clearly demonstrated that CAD in CT colonography is one of the hot topics in MDCT of the gastrointestinal tract. In another scientific session entitled “Small bowel and appendix”, 8 of 10 presentations explored various aspects of MRI in imaging of the small bowel (mostly for inflammatory bowel disease) while only one presentation referred to MDCT in the diagnosis of bowel endometriosis. The authors of this presentation concluded that, although MDCT is effective in diagnosing bowel endometriosis, the X-ray dose has to be optimized.

ECR 2008: Categorical Course in Multidetector CT

During last ECR 2008, the Categorical Course on Multidetector CT was repeated after its success at ECR 2007. The course was again organized by Drs. Mathias Prokop from the University Hospital of Utrecht and Carlo Catalano from La Sapienza University of Rome.
The course consisted of 8 sessions, each of 90 minutes with three different lectures. All aspects of MDCT were reviewed starting from the technical aspects going through all clinical applications. Most speakers were the same as last year with a few exceptions. All were very experienced on each topic and provided exceptional cases and results that can be achieved by the correct use of MDCT. The content was in general well balanced. Special highlights (with many participants) were the topics in which there is a known rapid development, such as cardiac CT, brain perfusion, (small) bowel imaging and trauma.
The course was held in room B, which was full in all sessions. On average, there were 300 radiologists attending each session.
On Friday morning, during the first session after the first lecture on the technical aspects of MDCT and the new advances provided by the different vendors, Dr. Dominik Fleischmann from Stanford University illustrated the importance of a correct intravenous administration of contrast agents. In the same session, an explanation was given on radiation exposure in CT and on how to reduce the dose in the different CT applications, utilizing automatic exposure control systems and dedicated protocols.
The clinical sessions provided information on the advantages and limitations of CT and especially of MDCT in different body areas. Most lectures also provided comparisons with other imaging modalities, mainly with MRI and ultrasonography.
In all sessions, examples were shown on what can be achieved with current scanners but also on the advantages that new scanners may provide. In fact, possible functional applications were demonstrated in the evaluation of lung parenchyma, the brain and also the heart and abdominal organs. In this regard, particularly interesting were the results that can be achieved with dual energy CT in the assessment of the lungs, liver, abdominal organs and brain. An example is the possibility of avoiding pre-contrast scanning and of generating simulated unenhanced images by subtracting two different data sets obtained at different energies after contrast agent administration. Dual energy CT may also become an important tool in oncological imaging, specifically in perfusion assessment before and during treatment with new antineoangiogenic drugs.
Many attendees were extremely interested in less diffused applications, such as the evaluation of the spine and the skeletal system. During the course, it became apparent that MDCT was indicated in this area as an adjunct examination to MRI and that the two techniques should not be considered alternatives but as integrated modalities that together provide a better diagnosis of spinal pathologies.
Dr. Novelline, chairman of the Emergency Radiology Department at Massachussets General Hospital, clearly demonstrated the importance of MDCT in the acute-phase examination of patients with polytrauma. With a single, fast examination, it is possible to evaluate the head, neck, spine, limbs and internal organs of the thorax and abdomen.
Particularly interesting and very well attended were the sessions on the heart and vascular system, in which MDCT provides excellent results and has opened a new frontier in noninvasive imaging. Apart from well established applications, it was also shown that MDCT is becoming increasingly important in the assessment of plaques and the atherosclerotic burden.
In summary, the overall impression was very favorable in terms of quality and attendance of this course. Given the continuous evolution of MDCT, it is worth repeating this course at the next ECR or in another large meeting.

MDCT angiography at ECR 2008

A scientific session entitled "CT angiography and perfusion" was held on Friday, 7 March 2008. Moderated by I.M. Björkman-Burtscher (Lund) and J. Walecki (Warsaw), the session provided 10 interesting presentations regarding MDCT angiography.
Watanabe and co-authors from Suita, Japan, studied dual energy bone removal CT angiography for the evaluation of intracranial aneurysms or stenoses; bone removal was successfully achieved in all 6 patients studied, with good results in 4 patients and moderate results in 2 patients. Bone removal techniques were also investigated by Papke et al. from Duisburg, Germany; while performing intracranial CT angiography in 15 patients, they found that subtraction of a non-enhanced bone mask with “neuro-DSA” was superior to dual energy CT bone removal.
Another study by Papke et al. compared the shape of intracranial aneurysms as delineated by 16-row MDCT angiography and by 3D rotational angiography in a phantom model; there was a high correlation between the two modalities in defining aneurysmal shape.
Psychogios and co-workers from Goettingen, Germany, evaluated the value of CT angiography in peri-interventional diagnostic imaging. CT angiography was found to be highly reliable in detecting peri-interventional subarachnoidal and intracranial hemorrhage, while it was less reliable in predicting early signs of infarction. CT angiography was also the topic of a presentation by Gao et al. from Beijing, China. These researchers compared dynamic CT angiography to helical CT angiography with 64-slice MDCT in the diagnosis of MCA stenoses in patients with transient ischemic attacks. They reported that dynamic CT angiography, using data from the perfusion scan, can replace helical CT angiography.
Rijsdijk from Utrecht, Netherlands, evaluated the relationship between vasospasm and cerebral perfusion after subarachnoidal hemorrhage: increasing degrees of vasospasm led to decreased CBF and CBV values and to increased MTT and TTP values. Another study by Rijsdijk assessed global and focal cerebral perfusion after aneurysmal subarachnoidal hemorrhage. Delayed cerebral ischemia appeared to be a focal or multifocal process rather than a global one.
Borny et al. from Kortrijk, Belgium, investigated the ability of perfusion CT parameters to differentiate penumbra from infarct core in patients with acute stroke, and found that an absolute CBF cutoff value of 10 ml/100 g min was the best parameter. Changes in perfusion parameters of double CT perfusion, as predictors of outcome in ischemic stroke, were the focus of study of Langner et al. from Greifswald, Germany. Changes in rCBF within the first 48 hours had high predictive value for the early neurological outcome.
Finally, Smits and co-workers from Netherlands compared the cost-effectiveness of various CT scanning strategies in patients with minor head injury: the Canadian CT head rule was found to be the most cost-effective.

New MDCT approaches to head and neck examinations at ECR 2008

One of the ECR scientific sessions dedicated to head and neck radiology focused on "new examination approaches". Although the session, moderated by R. Maroldi (Brescia) and A. Trojanowska (Lublin), covered different imaging modalities, there were 5 interesting presentations on MDCT.
Baum and co-authors from Erlangen, Germany, studied the influence of different mAs products on image quality in MDCT of the head and neck region. They reconstructed images with a slice width of 3 mm at effective tube currents of 160, 120, 80 and 40 mAs. Mean image noise was similar at 80, 120 and 160 mAs for the oropharynx, larynx and thoracic inlet, but image quality was significantly different at 40 and 80 mAs for the larynx and thoracic inlet.
Lee et al. from Ansan, Korea, compared different scan delays and total volumes of contrast media in order to optimize scan parameters for MDCT of the head and neck region. They found that a reduction of total contrast media volume could be counterbalanced by an optimization of scan time delay.
Coppenrath and coworkers from Munich and Neuherberg, Germany, compared the doses of dental MDCT and dental cone beam CT in a phantom study. Cone beam CT was found to have a lower dose than dental MDCT. However, both methods are low-dose examinations.
Otani et al. from Akita, Japan, evaluated 3D-CT angiography in the head and neck region using bone removal software: AutoBone Xpress reduced post-processing time and gave good results regarding vascular delineation.
Finally, Yerli and co-workers from Izmir and Ankara, Turkey, compared magnetic resonance imaging (MRI) and dynamic contrast-enhanced MDCT in the diagnosis of parotid tumors in 18 patients. The diagnostic accuracies of MRI and MDCT were 86% and 81%, respectively.

MDCT of the skull base and temporal bone at ECR 2008

A scientific session with several interesting presentations on MDCT in head and neck imaging was held on Tuesday, 11 March, 2008. Of the 10 presentations in this ECR session, 5 focused on MDCT.
Verbist and co-authors from Leiden, Netherlands, evaluated four 64-slice MDCT systems (Toshiba, Philips, GE, Siemens) in postoperative imaging of cochlear implants. All scanners met the technical requirements for acquiring adequate postoperative data in patients with cochlear implants. The systems differed, however, in the degree of visibility of the cochlear implant and in the quantitative assessment of electrode contact.
In other presentations, Lee et al. from Seoul, Korea, demonstrated the CT findings of various first branchial anomalies with detailed anatomy and morphology. Katsaros and co-workers from Athens, Greece, described their experience with both CT and magnetic resonance imaging of congenital deformities of the ear and proposed a new classification scheme. Iaia et al. from Newark, USA, evaluated the CT-morphological diagnosis of superior semicircular canal dehiscence syndrome and found that MDCT with multiplanar reformations of the semicircular canal improved diagnostic accuracy. Zhao et al. from Jinan, China, studied the depiction of traumatic ossicular chain separation with MDCT and concluded that additional MIP reformations increased diagnostic accuracy.

MDCT Technology News from ECR 2008 – Toshiba and GE

At the Toshiba symposium at ECR 2008 in Vienna, visitors had the opportunity to see the first clinical images acquired with the new, 320-row, 16-cm detector installed on the Aquilion One scanner. CT images were provided by La Charité Hospital, Berlin, Germany and Leiden University, Leiden, Netherlands.
For heart imaging, the most obvious benefit of this new scanner is the absence of step artifacts in the z-axis due to the very large z-coverage. A large reduction in radiation dose is expected by the use of the prospective mode on the basis of a one-beat acquisition. These preliminary results must be confirmed in larger series of patients with different clinical conditions, especially high or variable heart rates.
The new Toshiba scanner may also permit some new, unexpected applications, for example in thoracic imaging in children, due to the possibility of full coverage of the thorax in sequential mode: this makes dynamic evaluation of the airways possible and may allow clinicians to monitor for changes in upper airway caliber over time. For brain imaging, whole brain perfusion studies are now possible, with clear advantages for detection of ischemia in cases of acute stroke. Interestingly, 4D imaging allows comprehensive anatomical evaluation of complex cerebral arteriovenous malformations, with 3D images during both arterial and venous phases within the same injection. With this new CT technology, all the contrast medium injection protocols must be reconsidered.
New scanner technology was also presented by GE: in this case, new detectors based on Gemstone technology provided improved image quality. At this presentation, the future availability of dual-energy scanners, based on a fast kV switching within a single source, was confirmed. Compared to the double-tube technology, this will avoid the problem of scatter artifacts, but acquisition at the same effective tube current (mAs) using two different energy levels raises issues about image quality at low kilovoltage. With many improvements, the 64-slice detector technology remains the cornerstone of CT technology at GE.
In conclusion, ECR 2008 confirmed the choices of the CT vendors as announced at RSNA 2007: the race is now ongoing with completely different technological strategies for the four main manufacturers.

Clinical practice guidelines in CT urography

The European Society of Urogenital Radiology (ESUR) recently published clinical guidelines for multidetector CT urography [1]. The authors defined CT urography as a diagnostic imaging examination of the kidneys, ureters and bladder, and stated that this technique uses "multidetector CT with thin-slice imaging, intravenous administration of contrast medium, and imaging in the excretory phase".
The guidelines are based on a systematic review of the English and German literature since 1995. Since the evidence supporting various CT urography techniques and applications is limited (randomized controlled trials have not yet been reported), expert opinion from radiologists at the 2006 and 2007 annual ESUR meetings was also considered.
The document is organized in three main sections: indications, technical aspects, and imaging protocols. CT urography is recommended as the first examination in patients with macroscopic hematuria and in those suspected of having urothelial neoplasia; the technique is also valid in the diagnosis of microscopic hematuria and bladder cancer. The second part of the document provides detailed information on preparing patients for the examination, administering contrast medium, performing excretory phase imaging, analyzing the data, and understanding and minimizing radiation dose. The document closes by proposing a three-tiered approach to CT urography, using distinct imaging protocols when a patient's clinical features suggest: (I) limited benign disease, (II) extensive benign disease or possible malignancy, and (III) high probability of malignancy.

1. Van Der Molen AJ, Cowan NC, Mueller-Lisse UG et al. (2008) CT urography: definition, indications and techniques A guideline for clinical practice. Eur Radiol 18:4-17

Cardiac CT: expert consensus on clinical uses

The state of the art of cardiac CT has been recently reviewed by a joint working group of the European Society of Cardiology and the European Council of Nuclear Cardiology [1]. Authored by 14 European radiologists and cardiologists, the document offers an expert consensus on appropriate clinical applications, potential indications, and current challenges in the field of cardiac CT.
The paper begins with a brief review of multidetector CT technique applied to cardiology, touching on the use of electrocardiogram gating, contrast medium application, data acquisition and radiation exposure. The bulk of the 26-page document is dedicated to cardiac applications of CT, in particular the imaging of coronary arteries, coronary plaques, ventricular function, myocardial viability, and cardiac valves and veins. For each application, the authors review the relevant literature, often using tables to compare the evidence of different studies, and they summarize the evidence into a concise clinical recommendation. The paper closes with a call for establishing guidelines for the development of cardiac CT training programs. Moreover, the authors note that cost-effectiveness studies are needed to support reimbursement schemes that correspond to appropriate clinical uses of cardiac CT.


References

1. Schroeder S., Achenbach S., Bengel F. et al. (2008) Cardiac computed tomography: indications, applications, limitations, and training requirements. Eur Heart J 29(4):531-556
   

ECR dignitaries in radiology, 2008

In anticipation of the European Congress of Radiology (ECR), to be held on 7-11 March 2008 in Vienna, the European Society of Radiology has named dignitaries in the field of radiology for 2008. This year, nine radiologists will receive recognition in one of five categories.
A lifetime achievement award will be given to Albert L. Baert, who is cited for outstanding scientific accomplishments, particularly in lymphography, angiography and contrast-enhanced body CT, and for excellent leadership as president of the ECR and the European Association of Radiology and as editor of European Radiology.
A gold medal will be awarded to Nicholas Gourtsoyiannis, whose clinical work has focussed on gastrointestinal and abdominal radiology. Prof. Gourtsoyiannis has also made outstanding contributions to the field of radiology through his work as founding member, president and director of numerous associations and their conferences (including the ECR) and as editor and editorial board member of several scientific journals.
Honorary membership in the European Society of Radiology will be given to R. Gilbert Jost, Frederick S. Keller, and Lizbeth M. Kenny for their important work in the field of radiology. Three additional radiologists – Jürgen Hennig, Christiane K. Kuhl, James H. Thrall – have been selected to give lectures in honor of Wilhelm Conrad Röntgen, Peter E. Peters and Josef Lissner, respectively. Finally, Ernst Pöppel has been chosen to present the ECR 2008 inaugural lecture, entitled "Images in the brain – pictures in the eyes".
Biographies of these distinguished radiologists, and of the 2006 and 2007 dignitaries, are available at www.myesr.org.

Stanford's 10th annual MDCT symposium

On 13-16 May 2008, at the five-star Wynn resort and casino in Las Vegas, Stanford University's Department of Radiology will hold its tenth annual International Symposium on Multidetector-Row CT. The program is accredited as a continuing medical education event for both physicians and technologists. The symposium will focus on advances in the field of MDCT and will provide participants with practical information for optimizing scanning protocols and interpreting imaging data.
Directors Geoffrey Rubin and Gary Glazer, both of Stanford University's School of Medicine, have put together an intense program, with about 175 ten-minute presentations given on days that begin at 7 am and finish at 6:30 pm. Altogether, 46 guest faculty – mostly from the US but also from Germany, Italy, the Netherlands and Japan – together with 18 Stanford University faculty will speak. A break from this rhythm will be provided on the second day, with the sixth annual "workstation face-off". Here, radiologists will demonstrate in real time how to elaborate clinical datasets on different commercial workstations, and participants will be able to assess for themselves the advantages of each system.
The rich program will be complemented by concomitant hands-on workstation training opportunities, a trade exhibit of products from manufacturers and publishers, practical case-reading sessions, and events organized by industry partners. Futher information on the program and registration details are available at radiologycme.stanford.edu.

Cardiovascular CT and MRI: 6th European meeting

Cardiac imaging is pushing the technology of CT and MRI to continuous improvements, and is therefore making knowledge of the latest technology crucial for radiologists and cardiologists. In cardiovascular imaging, CT and MRI are increasingly used as complementary techniques in daily pratice, depending on each patient's pathology and presentation.

This European congress, the only one in Paris on this topic, will focus on the latest technological developments and the techniques for optimising both CT and MRI, including safety aspects. Internationally recognized speakers will present the state of the art of vessel imaging, including coronary arteries, myocardium and heart anomalies.

The meeting is being organised by Jean-François Paul of the Hôpital Marie Lannelongue and J. Garot of CHU Créteil, France. It will be held on 6-7 June 2008, in the center of historical Paris, and the presentations will be in French or English with simultaneous translation.
More information on the program and on how to register is available at www.diagest.com.

Excellence in radiological research: ART

Recent Medline entries simply signed by researchers from a program for the Assessment of Radiological Technology (ART) may raise astute readers' curiosity. ART is an educational and research program organized by the Department of Radiology and Department of Epidemiology and Biostatistics of Erasmus University Medical Center, Rotterdam. Members of ART are clinical researchers and students of masters and doctoral programs in these departments, as well as collaborators in other departments at Erasmus and at other universities in the Netherlands and United States.

This network of researchers is dedicated to evaluating technology for diagnostic imaging and for image-guided treatment, using knowledge of clinical epidemiology, decision sciences and technology assessment. Moreover, the researchers are actively engaged in developing methods for evaluating imaging procedures. The group has 25 papers indexed in Medline since 2001, including numerous meta-analyses, randomized controlled trials and cost-effectiveness analyses. This research network seems to show that collecting the best medical evidence is not just a science but also an ART.

Selected literature update: new volume on MDCT radiation dose

Inserted this month in MDCT.net's literature database are selected contents from the volume entitled Radiation dose from adult and pediatric multidetector computed tomography, edited by Denis Tack and Pierre Alain Gevenois, from Hôpital Erasme, Brussels. The book is addressed to general and specialized radiologists, referring physicians and other professionals involved in MDCT, and aims to increase understanding about radiation exposure during CT and how to manage it.

The 17 chapters of the book are divided into two sections, one on the radiation risks of MDCT and the other on clinical solutions for the reduction of radiation exposure and the optimization of image quality. From the first section, chapters selected for MDCT.net include one that reports an analysis of different European surveys on the collective radiation exposure from CT, and three chapters on technical aspects of imaging that determine radiation dose. From the second section, selected chapters discuss the optimization of radiation dose in specific clinical applications and radiation risk management in lung cancer screening programs.

More information on this book: www.springer.com

See also the book review by Professor Jean-François Paul on MDCT.net.

Evidence-based radiology: a short series

Evidence-based medicine, defined as "the integration of current best evidence with clinical expertise and patient values" can be put into practice by following a 5-step paradigm. These steps are briefly: (i) define questions to guide the search for evidence, (ii) carry out the search, (iii) assess the retrieved information using validated methods, (iv) apply this information in clinical practice, and (v) evaluate the clinical outcomes.

The process of evidence-based practice has recently been illustrated in a short series of papers published in Radiology. The first two steps – defining realistic clinical questions and searching the literature for evidence – are the topic of the first paper in the series (1). The paper considers the clinical scenario of suspected occult gastrointestinal hemorrhage, and takes readers through the steps of formulated questions to guide searching and then searching effectively on PubMed and other radiological resources. Subsequent papers in the series focussed on assessing the literature on diagnostic and interventional radiology and evaluating systematic reviews and meta-analyses in radiology (steps 3 and 4), and finally evaluating the outcomes and understanding the issues (step 5).

References

1. Staunton M. (2007) Evidence-based radiology: steps 1 and 2—asking answerable questions and searching for evidence. Radiology 242:23-31

Anticipating ECR 2008: abstract volume now online

The 2008 annual meeting of the European Society of Radiology is now just one month away. To be held on 7-11 March at the Austria Center Vienna, the European Congress of Radiology (ECR) expects 17 000 participants from 94 countries.

ECR attendees will be able to choose among 1700 scientific presentations in the forms of papers and exhibits, organized into 17 topics. The top three topics, by number of presentations, are neurology, interventional radiology and musculoskeletal radiology. Presentations will be given by delegates from 29 countries. From Europe, the most actively participating countries are Germany (with 263 presentations accepted), followed closely by Italy (244 presentations), Spain (151 presentations) and the UK (129 presentations).

To help attendees optimize their time while at the ECR, an online program planner and abstract viewer is now available (http://tinyurl.com/3cd97f). This free interface permits one to browse the program by topic, date and type of session and to search on specific topics using a multifield form. A further feature of this online program planner is the ability to create a personalized itinerary for the 5-day conference, in order not to miss a single important presentation.

European School of Radiology in China

RSNA 2007

MDCT at RSNA 2007

Association profile: Cardiovascular and Interventional Radiological Society of Europe

New adaptive CT scanner installed at University Hospital Erlangen

by V. Matarese

Selected literature update: MDCT in patients with acute chest pain

 
References

1. Coles RD, Wilde P., Oberhoff M. et al. (2007) Multislice computed tomography coronary angiography in patients admitted with a suspected acute coronary syndrome. Int J Cardiovasc Imaging 23:603-614
   

by V. Matarese