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december 2007
European School of Radiology in China | Appreciation of radiation exposure from CT: survey of pediatric surgeons | Association profile: European Society of Gastrointestinal and Abdominal Radiology | RSNA 2007 | MDCT at RSNA 2007 | RSNA 2007 - Brain and stroke imaging with MDCT | RSNA 2007 - Brain aneurysms, imaging and intervention | RSNA 2007 - Carotid artery disease session at RSNA | RSNA 2007 - Brain hemorrhage session | RSNA 2007 - Vascular disorders of the spine | RSNA 2007 - The multislice race is still going on | RSNA 2007 - A new "intelligent" iCT scanner from Philips | RSNA 2007 - CT news from Siemens Medical Solutions |
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by V. Matarese |
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The Radiological Society of North America (RSNA) recently held its 93rd scientific
assembly and annual meeting in Chicago, from 25 to 30 November 2007. The theme of this year's
meeting was "connecting radiology", an appropriate choice considering the importance of information
and communication technologies to the field of radiology. The theme was also important in that the
meeting brought together almost 62,000 radiologists and related healthcare professionals, including
more that 7000 international colleagues. This is, in fact, the largest international medical
congress in the world.
RSNA 2007 offered to the visitor more than 2200 presentations and posters, 250 refresher courses and 700 commercial vendors' exhibits. The meeting dealt with 16 specialistic subject areas: breast imaging; cardiac imaging; chest imaging; emergency radiology; gastrointestinal imaging; genitourinary imaging; health services, policy and research; molecular imaging; musculoskeletal imaging; neuroradiology, head and neck imaging; nuclear medicine; pediatric imaging; physics; radiation oncology and radiobiology; informatics; and vascular and interventional radiology. In the following articles, MDCT.net's board members in attendance have reported on what they found to be the most important highlights of the conference. by V. Matarese |
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During the 93rd scientific assembly and annual meeting of the RSNA, a large number of
scientific and educational sessions was devoted to multidector computed tomography.
One symposium, held in the Arie Crown Theater, was entitled “CT acquisition and visualization: the state of the art”. In this session, two major experts, Drs. Willi Kalender and Eliot Siegel, reviewed the technical innovations in CT including 64- and 256-slice MDCT scanners, flat-panel detectors and dual-energy CT. The two speakers also discussed the clinical methods that are facilitated by these new technologies and emphasized the importance of advanced visualization techniques in routine clinical practice. The technical and clinical limitations of current CT systems were explained with several examples. They stressed that it is important to know each patient's dose during modern CT and therefore explained the different methods of dose reduction. Finally, the speakers revealed their ideas on the future of CT, with some possible innovations in terms of speed of acquisition and improvement of spatial resolution and image quality. In an Interactive Session, the importance of radiation dose in MDCT was discussed from both American and European perspectives. It was explained that vendors approach this problem in different ways, aiming at a significant dose reduction but trying nevertheless to maintain or even improve image quality. In this session, the risks associated with radiation dose from MDCT in adults and children were reviewed. It was noted that the approaches to reduce radiation dose in the pediatric population could also be used in adults. Many clinical sessions were devoted to the role of CT in specific fields. One of the Case Review Sessions devoted to cardiac CT was organized in conjunction with North American Society for Cardiac Imaging (NASCI). The Cardiac CT Case Review consisted of four courses, during which the normal coronary anatomy and variants were shown, as well as coronary artery disease, arterial and venous by-pass grafts. Importance was also given to valves and cardiac function, pulmonary veins and pericardium, adult congenital heart diseases and incidental non-cardiac findings. The gastrointestinal series offered two separate, 150-min sessions. The first was devoted to CT colonography, while the second focused on imaging the liver with CT vs. MRI. For what regards CT colonography, during the scientific assembly, results were presented of a large multicenter trial conducted in 15 institutions in the US, which recruited 2600 asymptomatic subjects over 2 years. The study found that CT colonography is highly accurate in detecting intermediate and large polyps and has an accuracy similar to that of colonoscopy. The study also showed that on average there is no statistically significant difference in accuracy between primary 2D review and primary 3D review. The main implication from this study is that radiologists with appropriate training in CT colonography review can use either primary 2D or primary 3D review, if the exams are obtained with at least a 16-row scanner. The importance of CT in the acute patient was also emphasized by several scientific presentations. Some of them noted that in MDCT angiography, whole-body imaging offers several advantages over focused CT. In fact, the results from a large multi-traumatized population showed no statistically significant difference between the two protocols. Whole-body imaging is faster and provides high resolution images of the cervical, thoracic and lumbar spine, chest, abdomen and pelvis. The focused protocol implies a higher radiation dose and longer acquisition time, while the whole-body approach is just a sweep with no overlapping zones between segments. Many scientific presentations demonstrated differences in terms of enhancement and image quality by using highly concentrated iodinated contrast agents. Results were shown for what concerns not only CT angiography and vascular imaging with CT but also abdominal CT and parenchymal assessment. In fact, lesion conspicuity has been shown to be greater with highly concentrated contrast agents, especially in liver imaging. Again, during the 2007 RSNA meeting, many sessions were devoted to MDCT and all its different aspects. New developments, radiation dose and the attempts to reduce it, and all clinical applications were all given equal importance and emphasis. by C. Catalano |
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november 2007
Cardiovascular and Interventional Radiological Society | New adaptive CT scanner | MDCT and acute chest pain | Most recent results from the IMPACT study |
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Since its founding, CIRSE has organized annual meetings in European cities, and recent levels of attendance have exceeded 4000. The 2007 meeting was recently held in Athens and the 2008 meeting is scheduled for Copenhagen. While interventional radiology is the major emphasis of the meetings, new technologies are also represented. Finally, through the CIRSE Foundation, the association has created the European School of Interventional Radiology and will organize the first European Conference on Interventional Oncology, to be held in April 2008 in Florence, Italy. More information is available at www.cirse.org and www.ecio2008.org. by V. Matarese |
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The study recruited patients who presented to the emergency room with acute chest pain suggestive of coronary syndrome and who needed further investigation with conventional coronary angiography (CCA). Patients were excluded if they required immediate CCA, were hemodynamically unstable, or had several other clinical conditions. Before CCA, patients underwent MDCT coronary angiography with ECG-gating, on a 16-slice scanner; contrast enhancement was achieved with iomeprol-400. Coronary arteries were scored in 11 segments according to the AHA classification. The final diagnosis was considered that from CCA. During the study period, 365 patients were prescribed CCA for acute chest pain and were thus invited to participate in the study. Of these, 120 enrolled while the remaining 235 patients were excluded for clinical reasons (including need for immediate angiography), lack of consent or MDCT scanner time, etc. For 7 of the enrolled patients, full data were not available, leaving 113 patients for analysis. In this group, CCA revealed no pathology or non-significant stenosis in 26%, while 21%, 26% and 27% of patients had single-, double- and triple-vessel disease, respectively. With MDCT coronary angiography, diagnostic quality images were achieved in all 11 segments for 33 patients (29%) and in 5 proximal segments for 86 patients (76%). In detecting the presence of at least one significant stenosis, MDCT coronary angiography had a sensitivity of 92% and a specificity of 55%. The authors concluded that the diagnostic accuracy of this imaging modality for patients with acute chest pain was only moderate and less than that reported in earlier studies with elective or asymptomatic patients. This study found that MDCT coronary angiography has limited relevance in stratifying emergency patients and thus cannot offer the hoped for reduction in cardiac catheterization. Although the authors indicated that this was a pilot study, the study population was reasonably large and the data analysis was extensive. The authors noted--as limitations to their own work--the rapidly evolving technology which resulted in software changes during the course of the study. Whether new scanner technology, such as 64-slice scanners, will have greater diagnostic accuracy in this clinical setting remains to be tested.
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Most recent results from the IMPACT study
In the IMPACT study, 166 patients with chronic kidney disease were randomized to receive equivalent doses (40 g I) of either iopamidol-370 or iodixanol-320 (4 ml/s), prior to CE-MDCT of the liver or peripheral arteries. The first IMPACT article, published in the November 2006 issue of the same journal [LINK] showed that there was no significant difference in the incidence of CIN between the two groups.
The recent publication by Sahani et al. now reports that the effects of the intravenous injections on heart rate were also similar in the two groups. Moreover, iopamidol-370 provided significantly greater enhancement during the arterial phase and similar enhancement during the portal venous phase.
The new IMPACT abstract is available at www.investigativeradiology.com
Journées Françaises de Radiologie: annual meeting
This year, thematic sessions were organized with emphasize on specific points: osteoporosis, radioprotection, post-processing and PACS were the highlighted subjects.
Continuing medical education was promoted with organisation of specific CT post-processing treatment (including all main manufacturers). In particular, post-processing workshops for coronary artery imaging, virtual colonoscopy and detection of pulmonary nodules were organized.
Numerous scientific and thematic sessions were organized every day, and multislice CT presentations were numerous. In addition, multimodal thematic approaches were organized on specific topics, describing limitations and pitfalls of each modality in given clinical situations. Noninvasive cardiovascular imaging, especially cardiac CT and cardiac MR, is now a full part of radiological concerns.
In conclusion, Journées Française de Radiologie 2007 confirmed the leading place of this congress in the French-speaking world. It is organized every year at the end of October.
by JF Paul
European Society of Cardiac Radiology: 2007 annual scientific meeting
Rome, 18-20 October 2007
The 2007 annual scientific meeting of the European Society of Cardiac Radiology (ESCR) was held
in Rome from October 18th to 20th. The meeting, organized in collaboration with the Department of
Radiological Sciences of Sapienza, University of Rome, chaired by Prof. Roberto Passariello, was
attended by 475 delegates from all European countries; a few radiologists from North America, Asia
and even Australia also participated. The participation was extremely successful, with a 65%
increase in registrations compared to the previous 2006 edition.
The
scientific programme was well balanced with 5 educational sessions, 3 case
discussion sessions and 3 highlighted sessions. The opening session was dedicated to the role of
noninvasive coronary imaging by means of CT angiography, in which the current limits of diagnostic
coronary angiography and the advantages of CT were shown. Drs. K. Nikolau (Munich, Germany), H.
Alkadhi (Zurich, Switzerland) and P. Rogalla (Berlin, Germany) clearly demonstrated that the
possibility of visualizing not only the vessel lumen but also the walls represents a major
advantage of CT. Nevertheless, indications for coronary CT angiography are still debated, although
there is increasing evidence that patients with intermediate risk for coronary artery disease
should undergo CT.
Two lunch symposia dealt with the importance of contrast agent administration in
CT coronary angiography. The role of high concentration contrast agents was clearly shown in terms
of diagnostic accuracy of highly enhancing coronary arteries. The importance of good hydration of
patients at risk for developing contrast-induced nephropathy was also stressed. In fact, many risk
factors for coronary artery disease may also cause contrast-induced nephropathy.
Throughout the meeting,
the need to reduce patients' radiation dose, by different means according to
different vendors, was stressed. New developments in CT technology, such as dual source and
256-slice scanners, have further reduced the acquisition time and therefore have improved the
temporal resolution. No limitations are seen in scanning patients with high heart rate or
arrhythmias. Combined with these are strategies for reducing radiation dose, such as ECG-pulsing
with prospective gating and elimination of the spiral acquisition, which may further expand the use
of CT coronary angiography.
During the meeting
several sessions were devoted to the role of MRI, with morphological and functional
studies, especially in the assessment of the myocardium and its viability, inflammatory heart
diseases, cardiomyopathies, cardiac arrhythmias and the involvement of the heart in systemic
diseases.
During the scientific sessions, more than 90 oral communications and EPOS posters on cardiac
imaging were presented. Several clinical trials demonstrated an increasing accuracy of noninvasive
modalities. Finally, hands-on sessions were extremely successful in presenting
selected clinical cases, as seen with different 3D reconstruction software.
The meeting concluded on Saturday evening with the hope that the ESCR may further increase the
number of members. All delegates are invited to the 2008 meeting which will be held in Oporto,
Portugal.
by C. Catalano, Rome, Italy
Clinical competence statement on vascular imaging
The
Journal of the American College of Cardiology recently published a "clinical competence
statement" for the use of computed tomography (CT) and magnetic resonance imaging (MRI) in vascular
imaging applications [1]. The report was written by a task force representing the American College
of Cardiology Foundation (ACCF), the American Heart Association (AHA), the Society of
Atherosclerosis Imaging and Prevention, the Society for Cardiovascular Angiography and
Interventions, the Society of Cardiovascular Computed Tomography, the Society for Cardiovascular
Magnetic Resonance, and the Society for Vascular Medicine and Biology. This document, the first
task force statement to address vascular CT and MRI, aims to guide the assessment of physicians'
ability to perform specific procedures, by specifying the minimum experience, knowledge, and
technical skills required. The statement is based on scientific evidence and, when evidence is
limited, on expert opinion.
The document is divided into two parts that deal with vascular CT and vascular MRI separately;
each part contains sections on cognitive knowledge required for competency, formal training, and
maintaining expertise. Regarding vascular CT, the document reviews hardware, acquisition
techniques, image processing and interpretation, the use of contrast agents, and radiation
dosimetry. It discusses specific applications referred to anatomical areas, including aorta, upper
extremity arteries, extracranial cerebrovascular arteries, pelvic and lower limb arteries, renal
arteries, and mesenteric arteries. A short section focusses on CT venography. Finally, it addresses
various ways of obtaining training through formal fellowships and mentoring. Expertise is
maintained through both clinical experience with a regular workload and continuing medical
education.
by V. Matarese
- Kramer CM, Budoff MJ, Fayad ZA et al.; American College of Cardiology Foundation; American Heart Association; American College of Physicians Task Force on Clinical Competence and Training (2007) ACCF/AHA 2007 clinical competence statement on vascular imaging with computed tomography and magnetic resonance. A report of the American College of Cardiology Foundation/American Heart Association/American College of Physicians Task Force on Clinical Competence and Training. J Am Coll Cardiol 50:1097-1114
ICRP report on dose management in MDCT
A forthcoming report from the International Commission on Radiological Protection (ICRP) will
focus on managing radiation exposure during MDCT. The report is an update to the 2000 document
entitled "Managing patient dose in computed tomography", in which MDCT was briefly mentioned. The
report has now been updated in response to the enormous increase in MDCT applications since 2000
and the rapid evolution of MDCT technology.
The new report is structured in four major sections. First, MDCT technology is summarized and
compared to single-slice CT (SSCT) technology. In section two, the radiation dose from MDCT is
reviewed and compared to that from SSCT; this section provides perspectives on radiation dose and
discusses the responsibilities for managing patient exposure. The third section details the
operators' choices that affect a patient's radiation exposure during MDCT. The last section is
dedicated to clinical management of radiation dose, with reference to particular imaging
applications and patient groups. An appendix summarizes how to report CT radiation dose data.
Although the report is not yet published, interested persons can consult a draft report [1]
and the accompanying expert commentary [2].
by V. Matarese
- International Commission on Radiological Protection. Managing patient dose in multi-detector computed tomography. ICRP, Stockholm (draft version, 32/219/06 Dec.).
- www.icrp.org
New literature on the use of high-concentration contrast medium
A number of recent studies have investigated the use of contrast media with high iodine concentration as a means of obtaining better quality CT images. In general, high-concentration contrast medium (HCCM) helps achieve high arterial enhancement with a lower volume of contrast medium, and facilitates the timing of CT data acquisition after injection. The usefulness of HCCM in specific clinical applications is, however, the focus of current study. The availability of contrast agents at different iodine concentration makes it possible to perform controlled trials and thus to compare the effectiveness of HCCM vs. lower concentration contrast agents.
The benefits of using HCCM in neurovascular imaging have been investigated in three recent studies. von Tengg-Kobligk and colleagues used 400 mg/ml iodine concentration during 16-slice CT angiography of spinal cord feeding arteries in 18 patients with thoracic aorta pathologies, before and after endovascular aortic repair [1]. Schuknecht the same iodine concentration in 23 patients with vascular stenosis who were examined with 64-slice CT angiography [2]. König et al. [3] did a randomized controlled trial to compare CT perfusion image quality obtained using two different iodine concentrations (300 mg/ml and 400 mg/ml) in 21 patients with suspected cerebral ischemia. According to these authors, the benefits afforded by HCCM included high image quality, ability to delineate fine anatomy, and better therapeutic decision making.
by V. Matarese
- von Teng-Kobligk H., Bockler D., Jose TM et al. (2007) Feeding arteries of the spinal cord at CT angiography before and after thoracic aortic endografting. J Endovasc Ther 14(5):639-649
- Schuknecht B. (2007) High-concentration contrast media (HCCM) in CT angiography of the carotid system: impact on therapeutic decision making. Neuroradiology 49[Suppl 1]:S15-S26
- König M., Bultmann E., Bode-Schnurbus L. et al. (2007) Image quality in CT perfusion imaging of the brain. The role of iodine concentration. Eur Radiol 17:39-47
Selected literature update: new volumes from
Advances in MDCT
The fulltext of two issues of the series Advances in MDCT: an international literature review service has been indexed in MDCT.net's Selected Literature archive.
Head and neck imaging is the focus of the first issue of volume 3 (2007). The issue offers three reviews and four chapters of commented abstracts on head, neck and spinal imaging, and touches topics such as acute stroke, imaging optimization for the neurosurgeon and the head and neck surgeon, and MDCT of the maxillofacial region. The fourth issue of volume 3, dedicated to thoracic imaging, uses the same formula of reviews and commented literature. Specific topics include virtual bronchoscopy, imaging of chronic lung disease and pulmonary embolism, and image processing. All chapters are illustrated and fully cited.
by V. Matarese
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september 2007
CT colonography training standards | MDCT and acute chest pain | Lung cancer screening with CT | IMV company profile |
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Training for CT colonography: recommendations from a US task force
The American Gastroenterological Association (AGA) Institute recently published training standards for gastroenterologists regarding the use of CT colonoscopy (1). The AGA Institute—w hile considering CT colonography to be a controversial imaging test—recognized that this technology may in the future have a major impact in the field (2). Thus, the CT Colonography Task Force was formed to establish training criteria so that gastroenterologists will be able to accurately perform and interpret these studies.
The document, freely available from
Gastroenterology, begins with a summary of the current status of CT colonography and the
currently accepted indications for this diagnostic imaging modality. It then makes recommendations
regarding the qualifications of persons performing and interpreting the exams: formal theoretical
training is encouraged as well as practical experience involving the interpretation of at least 75
cases. A list of cognitive skills that physicians must have is also presented. Patient preparation,
scanner specifications and CT protocol are discussed. Finally, the task force suggests best
practices for reading CT images and reporting the findings.
Although these standards focus on the training of US gastroenterologists and on the use of CT
colonography within the American healthcare system, the document could guide the elaboration of
European training standards.
by V. Matarese
- Rockey DC, Barish M., Brill JV et al. (2007) Standards for gastroenterologists for performing and interpreting diagnostic computed tomographic colonography. Gastroenterology 133(3):1005-1024
- 2006 Position of the American Gastroenterological Association (AGA) Institute on computed tomographic colonography. Gastroenterology 131(5):1627-1628
Selected literature update: a consensus statement on the use of MDCT in the evaluation of
acute chest pain
The International Journal of Cardiovascular Imaging recently published a consensus statement on the use of MDCT in the assessment of patients with acute chest pain [1]. The consensus statement was authored by 19 radiologists, cardiologists and emergency physicians, from six countries, who formed an expert panel representing both the European Society of Cardiac Radiology and the North American Society of Cardiac Imaging. Goals of the joint panel were to combine experiences from countries with vastly different medical systems and to thereby overcome bias from local preferences and practices.
The first section of the document focuses on the triage of patients with acute chest pain in the
emergency setting. The authors describe the clinical presentations of acute coronary syndrome,
pulmonary embolism and acute aortic syndrome as well as alternative diagnoses. Much of the
remainder of the document is dedicated to the use of MDCT in these diagnoses and, in particular, on
the possibility that MDCT may be used for the "triple rule-out", i.e. simultaneously determining
with one diagnostic test if a patient has coronary, pulmonary or aortic disease. Regarding the CT
protocol to be used with these patients, the paper reviews scanner technology, patient preparation,
calcium scoring, specific CT angiography parameters, and image post-processing and evaluation. On
the basis of their analysis of the latest evidence, the authors conclude that minimally invasive
MDCT may improve management of patients with acute chest pain, and thus they encourage clinical
research on the use of MDCT in the emergency setting.
by V. Matarese
- Stillman AE, Oudkerk M, Ackerman M et al (2007) Use of multidetector computed tomography for the assessment of acute chest pain: a consensus statement of the North American Society of Cardiac Imaging and the European Society of Cardiac Radiology. Int J Cardiovasc Imaging 23:415-427
CT screening for lung cancer: updated clinical practice guidelines
The journal Chest recently dedicated an entire supplement to the updated clinical practice guidelines on the diagnosis and management of lung cancer. The first such guidelines were produced by the Health and Science Policy Committee of the American College of Chest Physicians (ACCP) in 2003; the revised guidelines are the work of almost 100 ACCP members and staff [1].
Although only 4 years have passed since the original clinical practice guidelines were written, a number of important advances warranted the revision [2]. One new issue regards the benefit of adjuvant chemotherapy after surgery in selected patients. New chapters are devoted to sonography-guided biospy and positron emission tomography. Still controversial topics are discussed in detail. For example, one chapter is dedicated to lung cancer screening using low-dose CT. Considering the insufficient evidence regarding the risk-benefit profile of CT-based screening, the authors recommended that this imaging modality be used for screening only within the context of a clinical trial.
The guidelines are published online. Some content is freely available.
by V. Matarese
- Alberts WM (2007) Diagnosis and management of lung cancer executive summary: ACCP Evidence-Based Clinical Practice Guidelines (2nd edition). Chest 132[3 Suppl]:1S-19S
- Alberts WM (2007) Introduction: diagnosis and management of lung cancer: ACCP Evidence-Based Clinical Practice Guidelines (2nd edition). Chest 132[3 Suppl]:20S-22S
Company profile: IMV Medical Information Division Inc
Although most radiologists are probably unfamiliar with the company International Marketing Ventures Ltd, it is likely that they frequently consult the company's website AuntMinnie.com. International Marketing Ventures (IMV) and its Medical Information Division produce the AuntMinnie Internet portal targeted to the medical imaging community, which offers news and resources about imaging technology, conferences and continuing education opportunities.
The 30-year-old IMV is also active in market research specifically focused on the medical
imaging and diagnostic instruments markets. From the corporate website imvinfo.com, visitors can
purchase market research reports on 15 medical imaging and 7 clinical topics. Regarding CT, the
company offers a market summary report regarding currently installed equipment (in the US), use of
contrast media, buying plans, operational budgets, etc. The benchmark report permits CT centers to
compare their performances with those of other facilities. The ServiceTrak product scores
manufacturers of CT scanners for quality of service and customer satisfaction.
These products may help directors of radiology departments make decisions regarding the purchase of CT equipment and the management of their facilities.
by V. Matarese
Clinical trials registries: a window on ongoing MDCT research
Traditionally, scientific congresses were the only official way of learning about research being conducted by colleagues around the world. Now, at least regarding clinical trials, it is possible to know what new studies are planned and ongoing, thanks to online clinical trials registries.
In 2005, the International Committee of Medical Journal Editors (ICMJE), a group of editors of general medical journals from 9 countries, began to require that researchers deposit information about new clinical trials in a public repository prior to recruiting patients [1]. Trial registration prior to enrolment was deemed a prerequisite for publication in the 12 ICMJE journals, but many other medical journals have adopted this recommendation. In the two years since adoption of this policy, the number of trials listed in online repositories has soared, providing useful information to researchers, research sponsors and, most importantly, patients seeking cures from experimental therapies. Among the clinical trial registries that meet ICMJE criteria are the US NIH's clinicaltrials.gov, the WHO's International Clinical Trials Registry Platform and the International Standard Randomised Controlled Trial Number (ISRCTN) Register.
Searching for multidetector CT in the titles and descriptions of registered studies reveals a number of trials experimenting with new applications for MDCT or using MDCT as an investigative technique. For example, researchers at St. Joseph's Healthcare in Ontario are conducting a large (900-patient) phase IV study to further evaluate if MD-CT angiography is comparable or superior to conventional coronary angiography. Researchers at the University of Aarhus are just starting enrollment for a study that will determine the accuracy of MDCT in assessing the morphology of coronary atherosclerotic plaques. At the Rikshospitalet-Radiumhospitalet HF in Oslo, two trials are nearing completion regarding the applicability of MDCT in patients who have received transplanted hearts and are thus at high risk of coronary artery disease.
Numerous other ongoing or completed trials are listed in these registries, which provide a brief overview of the medical question, a description of the study protocol and eligibility criteria, and contact information. When using these registries to find information on MDCT research, it is important to remember that, unlike Medline, entries are not indexed with standard keywords. Therefore, possible search terms are not only MDCT but also multidetector CT, multi-detector CT, and so on.
by V. Matarese
- Lane C., Horton R., DeAngelis CD et al (2007) Clinical trial registration: looking back and moving ahead. CMAJ 177(1):57-8
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august 2007
Liver imaging software | International Diagnostic Course in Davos | State of the art in MDCT |
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New liver imaging software from EDDA
A new liver imaging software was presented at the annual meeting of the Society for Imaging Informatics in Medicine (SIIM), held in June 2007 in Providence, USA. EDDA Technology presented IQQA-Liver Enterprise for abdominal applications of contrast-enhanced MDCT. This enterprise software, which runs on standard hospital PACS workstations, permits real-time evaluation of liver anatomy, lesions and vasculature. In particular, the software permits volumetric imaging with 3D segmentation and advanced 4D applications.
The IQQA-Liver software follows last year's launch of another "intelligent/interactive qualitative and quantitative analysis" (IQQA) product for chest imaging. Both applications take advantage of EDDA's "enterprise engine", which can be loaded onto any existing PACS without code-level integration, thereby simplifying installation and maintenance.
IQQA-Liver software has already been used in several leading Chinese hospitals, and has received regulatory approval from the US Food and Drug Administration and the Chinese State Food and Drug Administration. EDDA is headquartered in Princeton, USA and has a subsidiary in Shanghai, China. More information is available at www.edda-tech.com.
by V. Matarese
Selected literature update: a new volume from the International Diagnostic Course in
Davos
The 39th annual International Diagnostic Course in Davos (IDKD), held in March 2007, focused on diagnostic imaging and interventional techniques for diseases of the heart, chest and breast. Summaries of 31 workshops given by world renown clinicians have been published in the volume Diseases of the Heart, Chest and Breast. Edited by J. Hodler, G.K. von Schulthess and C.L. Zollikofer, this "Syllabus" is available in fulltext on SpringerLink.
Several of the workshops gave particular attention to multidetector CT and are therefore included in MDCT.net's literature database. For example, de Roos and Revel described the use of MDCT and MRI to investigate cardiac and pericardiac diseases. Grenier reviewed the use of MDCT to assess acute and chronic inflammatory and fibrotic lung diseases, of small and large airways, as well as obstructive lung diseases. Papaioannou and colleagues focused on volumetric CT of the tracheobronchial tree, especially as it aids presurgical planning.
Information about next year's course, which focuses on diseases of the brain, head & neck and spine, is available from www.idkd.org.
by V. Matarese
Symposium preview: State of the art in MDCT technology and applications
This coming October 2007, the "State of the art in MDCT technology and applications" symposium will be held in Düsseldorf, at the Radisson SAS Scandinavian Hotel. Sponsored by an unrestricted educational grant from Bracco, this 2-day event follows last year's symposium which was held in Amsterdam and for which audiovideo e-Lectures can be viewed online at MDCT.net.
This year's symposium focuses on curent examination techniques and advanced clinical applications using the latest-generation scanners. The symposium is organized in four sections dedicated to MDCT technology, neuro- and cardiovascular applications, abdominal applications, and safety issues particularly in at-risk patients.
The symposium will be accredited by the UEMS Section and Board of Radiology and the European Accreditation Council for Continuing Medical Education. A preliminary program and registration information are available from the Academy for Advanced Educational Projects.
by V. Matarese
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july 2007
Skeletal imaging |
News from ESGAR 2007 |
The CARE study
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MDCT practical course
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Skeletal imaging: a selected literature update
Among the publications inserted into MDCT.net's Selected Literature database for the month of June 2007 were 3 journal articles that focused on multidetector CT of bone structures.
Bauer and colleagues [1] assessed the feasibility of using MDCT to image the architecture of trabecular bone within a soft-tissue context. They studied 4 phantoms derived from proximal femoral heads (from patients who underwent total hip arthroplasty), alone and within a simulated torso composed of porcine tissue. Micro-computed tomography (MCT) was used as a reference technique for assessing parameters of trabecular bone. MDCT images of the femoral phantom were substantially affected by the presence of the simulated torso, which caused scattering artifacts and reduced the signal-to-noise ratio. Nonetheless, parameters of trabecular bone assessed with MDCT correlated with those determined by MCT, suggesting that MDCT can be used to image bone architecture even at deep anatomical sites.
Zhen et al. [2] developed a spiral MDCT protocol for imaging the adult temporal bone, working with fresh cadaveric heads. After imaging, thin-section anatomical slices were obtained to determine MDCT's ability to identify temporal bone details. All 50 anatomical structures seen on anatomical slices were fully identified on MDCT images, validating the authors' imaging protocol.
The third paper, by Milillo and coworkers [3], described a clinical study in which MDCT was used to assess osteonecrosis of the jaw, a side effect of bisphosphonate therapy for osteoporosis or malignant diseases. The study enrolled 38 such patients with symptoms of jaw osteonecrosis (e.g. temporomandibular joint pain, altered mouth sensations) which had been triggered by tooth extraction or endodontic treatment. MDCT showed alterations of facial bone in the upper or lower jaw in all patients and documented the short-term results of reconstructive surgical treatment. The authors noted, however, that osteonecrosis of the jaw should also be studied with MRI, which is considered superior in assessing the soft tissues.
by V. Matarese
- Bauer JS, Link TM, Burghardt A. et al. (2007) Analysis of trabecular bone structure with multidetector spiral computed tomography in a simulated soft-tissue environment. Calcif Tissue Int 80:366-373
- Zhen J., Liu C., Wang S. et al. (2007) The thin sectional anatomy of the temporal bone correlated with multislice spiral CT. Surg Radiol Anat 29(5):409-418
- Milillo P., Garribba AP, Favia G., Ettorre GC (2007) Jaw osteonecrosis in patients treated with bisphosphonates: MDCT evaluation. Radiol Med 112(4):603-611
FROM ESGAR -
Lisbon 12 - 15 June 2007
18th Annual Meeting and Postgraduate Course of The
European Society of Gastrointestinal Abdominal Radiology
The 18th annual meeting and postgraduate course of the
ESGAR was recently held in Lisbon, and it was successful for both the
organizers and the participants. Browsing through the program, it was evident that MDCT has a
distinctive role in cross-sectional imaging of the abdomen, although MRI and ultrasonography are
also well established imaging techniques for this purpose.
A major topic discussed in lectures, scientific sessions, lunch symposia and electronic poster
presentations was CT colonography. Although some data were presented on MR colonography as well, CT
colonography clearly is much better established. Issues discussed focused on the use of CAD,
radiation exposure, bowel preparation, political issues and the potential use of CT colonography
for nation-wide screening programs. Especially regarding screening issues, there were evident
differences in opinion among the different European countries.
In liver imaging, some discussion developed on the appropriate timing for arterial phase
imaging, but no really new data were presented. For imaging of focal liver lesions, more emphasis
was set on MRI, liver-specific MR contrast agents, and the potential value of diffusion-weighted
imaging than on MDCT.
Pancreatic imaging sessions were dominated by MDCT issues, including optimization of the iodine concentration for pancreas CT, the accuracy of MDCT in the preoperative evaluation of pancreatic carcinoma, and the differentiation of cystic lesions into benign or malignant forms with CT.
Regarding small bowel imaging, discussion on MDCT concentrated on emergency-related issues
(small bowel obstruction, gastrointestinal bleeding) and, although some data were presented on CT
imaging of patients with Crohn’s disease, the majority of Crohn’s disease-related papers focused on
MRI.
Last but not least, the extremely high value of MDCT in the workup of acute abdomen and
abdominal trauma was stressed in many presentations.
by AJ Aschoff, Germany -
Abstracts of the ESGAR meeting can be found in
Supplement 3 of volume 17 of European Radiology
The CARE study: Cardiac Angiography in REnally impaired patients
The results of the
Cardiac
Angiography in
REnally Impaired Patients (CARE) study were recently published in the American Heart
Association’s journal Circulation. The CARE trial is the largest, prospective, randomized,
double-blind comparison of the iso-osmolar iodixanol-320 with the low-osmolar iopamidol in
high-risk patients. The CARE study found that the rate of contrast-induced nephropathy (CIN) in
high-risk patients undergoing cardiac angiography or percutaneous coronary procedures was not
significantly different between patients who received iopamidol-370 and those who received
iodixanol-320.
The purpose of this multicenter, double-blind, randomized study was to prospectively compare
the incidence of CIN following administration of the nonionic monomer iopamidol-370 (796 mOsm/kg)
with that after administration of the nonionic dimer iodixanol-320 (290 mOsm/kg). A total of 414
patients with moderate-to-severe chronic kidney disease, including 170 with diabetes mellitus, was
evaluated. The CARE study results show that osmolality is not the sole contributing factor in CIN.
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june 2007
Low-dose MDCT in asbestos-exposed workers | A practical course in MDCT |
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Low-dose MDCT for lung cancer screening in asbestos-exposed workers: a selected literature
update
A recent addition to MDCT.net's Selected Literature database is an article by Das and colleagues (1) from Aachen, Germany, regarding the Asbestos Surveillance Program Aachen (ASPA). In this report, the authors presented baseline screening results for 187 persons at high risk for lung cancer but without a history of malignancy. The high-risk population was identified by ranking over 5000 former power-plant workers according to their age, asbestos exposure time and smoking habit. Subjects who entered the study had a mean age of 67 years and a mean asbestos exposure time of almost 30 years; 89% were current smokers and 10% ex-smokers.
Screening was performed using a 16-slice scanner, without contrast medium administration, and
following a low-radiation-dose protocol (mean effective dose, 1.1 mSv). Of the 187 individuals
screened, only 24 had no pulmonary nodules and 16 had nodules with a diameter exceeding 10 mm.
Overall, 9 subjects were identified with lung cancer (including 4 with advanced-stage
disease), giving a prevalence of 4.8%.
The authors comment that the prevalence of lung cancer in this high-risk population is the
highest ever reported in a low-dose MDCT screening study, possibly due to the selection of
highest-risk subjects on the basis of asbestos exposure time. According to the authors, only one
other screening trial considered both asbestos exposure and smoking habit to select at-risk
subjects, and reported a lung cancer prevalence of <1% (2). The differing results may be explained by the scanning
technology used (the earlier trial used standard spiral CT technology) or by differences in the
study populations' characteristics. Thus, this new report of a European lung cancer screening
program is welcomed, although the study is somewhat limited by its small population and sometimes
flawed scientific reporting.
by V. Matarese
- Das M., Muhlenbruch G., Mahnken AH et al. (2007) Asbestos Surveillance Program Aachen (ASPA): initial results from baseline screening for lung cancer in asbestos-exposed high-risk individuals using low-dose multidetector-row CT. Eur Radiol 17:1193-1199
- Tiitola M., Kivisaari L., Huuskonen MS et al. (2002) Computed tomography screening for lung cancer in asbestos-exposed workers. Lung Cancer 35:17-22
A practical course in MDCT: the fourth MDCT National Symposium
The Society of Computed Body Tomography and Magnetic Resonance (SCBT-MR) is holding the
fourth annual national symposium on MDCT, this coming September at the Westin Boston Waterfront
Hotel (Boston, USA). The course, directed by Sanjay Saini of Harvard Medical School, is intended
for practicing radiologists from both private and academic settings, as well as student
radiologists and physicians in other related fields. The 2-day course will be taught by 23
physicians, mostly from US universities, and has been sponsored by an unrestricted educational
grant from Bracco Diagnostics.
Goals of the national MDCT symposium are to impart knowledge of scanning protocols that can
be immediately applied in clinical practice. Specifically, the course addresses the following
topics: principles of MDCT, scanning techniques and radiation safety; correct administration of
contrast medium; common MDCT protocols for chest and abdomen; and procedures for oncology,
cardiovascular medicine and colonography. Further details about the course and an online
registration form are available at
www.mdct-apracticalapproach2007.com.
by V. Matarese
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may 2007
Dual-energy CT colonography | MDCT of aortic trauma | MDCT of acute abdominal pain | 64-slice coronary angiography | Diagnostic imaging of vertebral artery dissection | Cardiac CT |
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Dual-energy CT colonography on unprepped colon: in vitro testing
Researchers from Emory University School of Medicine (Atlanta, USA), headed by Sunit
Sebastian, studied the possibility that the dual-energy setting would permit performing CT
colonography on an unprepped colon. For the study, they employed a human colon model containing
simulated polyps and fecal matter. Preliminary results with this in vitro model were promising
(accuracy, 69%-87%) and the researchers are now planning a clinical trial of dual-energy MDCT
colonography. The possibility of screening for colon cancer without prior colonic preparation is
expected to increase patient compliance and thereby improve the chances of detecting colon cancer
early. The study was presented at the 107th annual meeting of the American Roentgen Ray Society,
held on 6-11 May 2007 in Orlando, USA. Adapted from a press release of the American Roentgen Ray
Society (www.arrs.org).
[from the Annual Meeting of the ARRS, Usa, May 2007 - by V. Matarese]
Diagnosis of aortic trauma with MDCT
MDCT may eliminate the need for catheter angiography in the diagnosis of aortic trauma.
Researchers from the Medical University of South Carolina (Charleston, USA), led by Scott
Steenburg, retrospectively reviewed the cases of over 500 patients who underwent contrast-enhanced
64-slice MDCT for suspected aortic injury; catheter angiography was also performed in a small
subset of these patients. Findings between MDCT and angiography were concordant in all cases. These
results suggest that, when aortic injury is identified with MDCT, confirmation by angiography is
not required. Thus, these patients can undergo needed surgery without delay, thereby reducing
morbidity and mortality. The study was presented at the 107th annual meeting of the American
Roentgen Ray Society, held on 6-11 May 2007 in Orlando, USA. Adapted from a press release of the
American Roentgen Ray Society (www.arrs.org).
[from the Annual Meeting of the ARRS, Usa, May 2007 - by V. Matarese]
Diagnosis of acute abdominal pain with MDCT
MDCT in the emergency room setting may prove advantageous in the diagnostic imaging of
patients with nonspecific acute abdominal pain. Researchers from Emory University School of
Medicine (Atlanta, USA) and Massachusetts General Hospital (Boston, USA), headed by Unni
Udayasankar, studied the possibility of using extremely low-dose MDCT of abdomen and pelvis to
replace the standard three-view abdominal radiography protocol. At comparable radiation doses, MDCT
gave better quality images and thus greater diagnostic confidence than radiography. According to
the authors of this study, patients with negative findings at MDCT can be confidently discharged
from hospital earlier. The study was presented at the 107th annual meeting of the American Roentgen
Ray Society, held on 6-11 May 2007 in Orlando, USA. Adapted from a press release of the American
Roentgen Ray Society (www.arrs.org).
[from the Annual Meeting of the ARRS, Usa, May 2007 - by V. Matarese]
Diagnostic accuracy of 64-slice CT coronary angiography
Researchers from the Azienda Ospedaliero-Universitaria of Parma (Italy) and Erasmus Medical
Center (Rotterdam, The Netherlands), led by Filippo Cademartiri, assessed 170 patients with
suspected coronary artery disease and divided them into two groups on the basis of the
intracoronary attenuation achieved during the imaging examination. Sensitivity and specificity for
detecting coronary lesions were higher for patients in which higher intracoronary attenuation was
achieved (96% and 97% vs. 91% and 93% for the low-attenuation group). These results suggest that
imaging parameters which increase attenuation, such as use of high iodine concentration contrast
medium, may improve the accuracy of 64-slice CT coronary angiography. The study was presented at
the 107th annual meeting of the American Roentgen Ray Society, held on 6-11 May 2007 in Orlando,
USA. Adapted from a press release of the American Roentgen Ray Society (www.arrs.org).
[from the Annual Meeting of the ARRS, Usa, May 2007 - by V. Matarese]
Selected literature update: diagnostic imaging of vertebral artery
dissection
MDCT.net is supported by a database of full text journal articles and book chapters selected
from the content published by Springer-Verlag. During the latest monthly update, 13 journal
articles were added, including two that discussed vertebral artery (VA) dissection.
VA dissection has an annual incidence of 1-1.5 per 100 000 persons (1), and 20% of affected patients are young or middle aged.
Dissection may occur in the intracranial (V4) segment or in any of the extracranial (V1-V3)
segments, and may be spontaneous or traumatic. Since VA dissection is a cause of posterior
circulation stroke, ischemic stroke and subarachnoid hemorrhage, immediate detection is crucial.
Moreover, since clinical manifestations of VA dissection are nonspecific, an accurate
diagnosis must be based on neuroimaging. Digital subtraction angiography (DSA) is commonly
used to diagnose VA dissection, but this method poses risks due to its invasiveness.
Noninvasive imaging modalities that may be used include color Doppler ultrasonography (CDUS),
magnetic resonance angiography (MRA) and multidetector CT angiography (MD-CTA) (1).
Pugliesi and colleagues (2) from Italy performed a retrospective comparison of CDUS and
4-section MDCT in 15 patients with VA dissection diagnosed according to clinical presentation and
conventional angiography. The dissection was accurately diagnosed with CDUS in 10 cases (60%
specificity, 66% sensitivity) and with MD-CTA in all patients. The authors concluded that MD-CTA is
a valuable diagnostic tool for VA dissection, particularly in cases of clinical suspicion with
inconclusive findings at CDUS.
Dissection of the V4 segment of the vertebral artery was addressed by clinicians working at
Chonnam National University Medical School (Korea) and at Stanford University Medical Center (USA)
(3). This review was organized in three parts, the first of
which summarized the clinical aspects of V4 segment dissection, including its pathogenesis,
symptomatology, clinical course and prognosis.
The second section discussed the radiological findings of catheter angiography, MRA and
MD-CTA. In particular, the authors recommended MD-CTA for patients with acute subarachnoid
hemorrhage due to a ruptured VA aneurysm, while they suggested to use MRA in patients with symptoms
of posterior fossa ischemia. The paper closed with a section on endovascular treatment.
by V. Matarese
- Flis C., Jager HR, Sidhu PS (2007) Carotid and vertebral artery dissections: clinical aspects, imaging features and endovascular treatment. Eur Radiol 17:820-834
- Pugliese F., Crusco F., Cardaioli. G et al. (2007) CT angiography versus colour-Doppler US in acute dissection of the vertebral artery. Radiol Med 112:435-443
- Yoon W., Seo JJ, Kim TS et al. (2007) Dissection of the V4 segment of the vertebral artery: clinicoradiologic manifestations and endovascular treatment. Eur Radiol 17:983-993
FROM ECR – Vienna 9 - 13 March 2007
Use of computed tomography to study the heart
The recent advances in CT technology permit direct, noninvasive study of the coronary
arteries. This avoids the need for long, complex procedures such as cardiac angiography, which
requires insertion of a catheter in a peripheral artery and its positioning at the level of the
heart through multiple direct injections of contrast medium in the coronary vessels. With the new
generation of multislice CT scanners, a detailed study of the coronary arteries can be performed in
a few seconds, with a simple intravenous injection of a smaller dose of contrast medium.
Furthermore, CT provides important information about atheromatous plaques restricting the coronary
lumen, the warning signal for myocardial infarction. Despite the lack of formal international
guidelines, multislice CT may develop into a widely used, noninvasive diagnostic tool for cardiac
and coronary artery pathologies in routine clinical practice.
From Bracco's Press Release
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april 2007
Carotid imaging with MDCT | Development of multislice CT | Problems with contrast agents | Beyond 64-slice-CT for cardiac imaging |
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Carotid imaging with MDCT: a scientific session at the ECR
One scientific session at the European Congress of Radiology, held 9-13 March 2007 in Vienna,
Austria, was dedicated to carotid imaging (Scientific session 315).
R.A. Bucek and coworkers from Vienna, Austria, evaluated the role of CTA quantification of
internal carotid artery stenosis (B-181). They assessed measurements of the luminal area versus the
luminal diameter in CTA and compared these to the luminal diameter measured in DSA. Inter-observer
variabilities were evaluated. Assessment of both the luminal area and luminal diameter correlated
well to the diameter measured in DSA. The inter-observer agreement was higher when the area was
measured than when the diameter was measured in MD-CT-angiography (MD-CTA). The authors therefore
recommend measurement of the area when quantifying a stenosis with MD-CTA.
The same group of authors also evaluated an automated CTA quantification of internal carotid
artery stenosis as a pilot study (B-182). Carotid artery stenosis was quantified according to
NASCET criteria by two experienced radiologists on axial images in 46 consecutive patients. The
results were compared to automated CTA quantification. Manually adapted automated CTA
quantification had a sensitivity of 44.2% and a specificity of 97.7%, while fully automated CTA
quantification had lower values: a sensitivity of 34.9% and a specificity of 93.1%. The authors
conclude that these methods are currently insufficient for clinical application.
A.A. Lemos and co-workers from Milan, Italy, assessed the importance of MD-CTA in the evaluation of carotid arteries in patients with multiple traumas (B-183). Injuries such as dissection, pseudoaneurysms and traumatic obstructions of the carotid arteries were recorded and compared with follow-up. Carotid injuries were found in 3.2% (16/507) patients with multiple traumas. 8 had a monolateral dissection, 2 bilateral dissections, 3 pseudoaneurysm, and 3 traumatic occlusion. The majority were found in flexion-extension injuries.
R.E. Brightwell from London, U.K., compared the intra-cerebral hemodynamic effects of carotid endarterectomy with carotid stenting by using early and late CT perfusion scanning (B-190). They evaluated 20 patients after carotid endarterectomy and 14 patients with carotid stenting 1 day and 6 weeks after the procedure with CT perfusion. Carotid endarterectomy and carotid stenting had similar outcomes on CT perfusion. Only the time to peak (TTP) was significantly less with carotid stenting, possibly as a result of a greater residual stenosis.
by B. Ertl-Wagner, M.D.
Development of multislice CT and current and future benefits for cardiac imaging
For years, technological development in CT heart study has been a “turbulent” process. Every
two years or so, new and improved hardware solutions come onto the market. Researchers have trouble
keeping up with the pace set by the market. For example, the results of the first clinical studies
on the effectiveness of 64-slice scanners are only being published now, yet more recent generations
(such as double-source systems) are already commercially available. Innovation in this field is
moving in many directions. Without doubt, one of the main problems with previous generations of
multislice CT scanners was low temporal resolution, which led to the generation of motion artifacts
when heart rates were greater than 70 beats/minute. Certainly, the ability to scan the coronary
arteries of patients with a high cardiac frequency without a deterioration in diagnostic accuracy
is one of the most important improvements, since the method can be used without requiring
medication with beta-blockers and also during cardiovascular emergencies. Another innovation is the
possibility of noninvasively studing coronary atheromatous plaques. CT assists identification of
atherosclerotic plaques which increase the risk of sudden obstruction of the coronary arteries and
myocardial infarction (“unstable” or “vulnerable” plaques). The ability to characterize coronary
plaques according to dimensions, remodeling index and density is likely to lead to new strategies
for diagnosis and treatment. Definition of the concept of coronary risk with respect to population
data, such as data from epidemiological surveys, will enable us to identify individuals at real
risk of coronary disease with greater accuracy.
From Bracco's Press Release
Problems in the use of contrast agents and potential benefits of contrast agents with high
iodine concentration (i.e. lomeron 400)
Intravascular contrast is important in imaging small-caliber coronary vessels (between 1 and
5 mm in diameter). The greater the attenuation difference between the blood vessel lumen and the
surrounding tissue (i.e. vessel wall and epicardial adipose tissue), the easier a small-caliber
vessel will be to image (e.g. 2 mm). To achieve a high attenuation difference, large quantities of
iodine molecules have to be present inside the vessel. This can be achieved in two concomitant
ways: 1, through a high intravenous flow of an iodinated contrast agent; and 2, with a high iodine
concentration in the contrast agent. The first parameter depends on a number of variables, such as
the access vessel dimensions and the capacity of the vessel through which the contrast agent is
injected. The second parameter depends solely on the chemical characteristics of the contrast
agent. A higher iodine concentration (for example, Iomeprol 400 mgI/ml) produces a virtually linear
increase in coronary intravascular attenuation. Other variables such as ejection fraction and
cardiac frequency may have a significant impact on the compactness of the contrast agent bolus in
the vein system of the arm and consequently within the aorta-coronary artery system. We know that
globally depressed myocardial function (i.e. reduced ejection fraction and low cardiac frequency)
keeps the bolus much more compact and produces higher artery attenuation than that achieved in
patients with normal or moderately depressed myocardial function.
From Bracco's Press Release
Beyond 64-slice-CT for cardiac imaging
After a rapid increase in the number of image slices since 2000 (by a factor of 4 every 2
years), it seems that an important step has been achieved with 64-slice CT. What will be the next
step ? We tried to guess the future of cardiac CT by asking the 4-slice CT manufacturers during ECR
2007 in Vienna. The future of cardiac CT is not clear and manufacturers are looking in different
directions. With the Somatom Definition (a dual-source CT unit) from Siemens, a new approach is
being proposed: using 2 tubes instead of one, the temporal resolution of an image is divided by a
factor of 2. Only 83 ms is now necessary to acquire a cardiac image, making it possible, in
principle, to get an image free of motion artefacts at any heart rate. However, the number of
row-detectors is still 32, and the detector width is limited. A mean of 9 s is required to get an
image of the whole heart. In the near future, larger detectors will be proposed to overcome this
limitation. Toshiba is working on a 256-row system, still in evaluation in Japan and the US. Such a
large system will potentially offer a real change by imaging the heart in one acquisition, with
greater consistency in image quality. Philips is also announcing a new large, 15-cm curved panel,
which may image the heart within a single heart beat. GE is currently working on a new acquisition
system, which should allow a considerable radiation dose reduction in a prospective fashion with a
64-slice row detector. Indeed, radiation dose reduction is an important issue for the development
of cardiac CT. Sequential dual-energy acquisition with one tube is also under study by GE. Thus, CT
technology is still evolving fast, and is driven by the requirements of cardiac CT to acquire a
perfect image in every case. The directions are different, but for sure these different approaches
will guarantee that the best progress is achieved in the future.
by JF Paul
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march 2007
CT technology | Imaging the small bowel | Acute pulmonary embolism | Buying a CT unit | Pre-operative lung cancer staging | CT colonography | AngioVis-ToolBox | Minimizing radiation risks |
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CT technology
Major manufacturers of CT units are using new technology to address the need to reduce
patients' exposure to radiation during multidetector CT. At this year's ECR, the CT scanners with
dose-reduction technology were: GE Healthcare's new Light-Speed VCT XT system designed for
cardiac imaging, Siemens Medical Solutions' Somatom Definition system with dual x-ray sources and
dual detectors, Philips Medical System's Brillance CT with a 64-channel configuration, and Toshiba
Medical System's new multidetector system called Activation 16.
Imaging the small bowel
Different imaging techniques can be used to visualize the small bowel wall and vascularity in
patients with inflammatory conditions such as Crohn's disease. CT enterography is one approach that
has particular advantages and limitations.
Acute pulmonary embolism
During the ECR symposium on the state of the art of pulmonary embolism diagnosis, speakers
discussed the risk of false-positive findings on multislice CT, the role of D-dimer testing, the
advantages of simultaneously assessing pulmonary arteries and cardiac function, and the associated
radiation burden.
Buying a CT unit
In the first session of the multidetector CT course, Prof. M. Prokop reviewed the factors
that radiologists should consider before purchasing a CT unit. According to the speaker, important
issues in the choice of a multislice CT unit include current clinical indications, need for full
cardiac imaging capabilities, and possibilities of upgrading or purchasing a new unit in the
future.
Pre-operative lung cancer staging
The interactive ECR session on lung cancer was dedicated in part to the roles of different
imaging modalities, in particular MDCT and PET-CT, for screening and staging of lung cancer, but
also discussed the public health impact of screening and the role of the radiologist in an
interdisciplinary team of physicians caring for patients with lung cancer.
CT colonography
During the ECR session on the state of the art of CT colonography, speakers debated the
advantages and limits of CT colonography compared to traditional colonoscopy in the search for
polyps and cancer. Moreover, they discussed the benefits of computer-aided diagnosis (CAD) software
in this medical context.
AngioVis-ToolBox
AngioVis-ToolBox is new software for the analysis and elaboration of CT angiograms of the
lower extremities.
Minimizing radiation risks
An ECR refresher course explained how to justify the use of multidetector CT in specific
clinical applications. The course reviewed current guidelines on the use of ionizing
radiation in medical procedures and introduced a new model for assessing the need for MDCT.
The model, a network of influence diagrams, is based on scientific evidence and permits clinicians
to assess the interactions among clinical variables, medical decisions and health outcomes. The
course also discussed the optimization of MDCT examinations.
