Small coronary calcifications are not detectable by 64-slice contrast enhanced computed tomography
by AG Van der Giessen, FJH Gijsen, JJ Wentzel et al.
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Abstract
Recently, small calcifications have been associated with unstable plaques.
Plaque calcifica- tions are both in intravascular ultrasound (IVUS) and multi-slice computed
tomography (MSCT) easily recognized. However, smaller calcifications might be missed on MSCT due to
its lower resolution. Because it is unknown to which extent calcifications can be detected with
MSCT, we compared calcifica- tion detection on contrast enhanced MSCT with IVUS.
The coronary arteries of patients with myo- cardial infarction or unstable angina were imaged
by 64-slice MSCT angiography and IVUS. The IVUS and MSCT images were registered and the arteries
were inspected on the presence of calcifications on both modalities independently. We measured the
length and the maximum circumferential angle of each calcification on IVUS. In 31 arteries, we
found 99 calcifications on IVUS, of which only 47 were also detected on MSCT. The calcifications
missed on MSCT (n = 52) were significantly smaller in angle (27° ± 16° vs. 59° ± 31°) and length
(1.4 ± 0.8 vs. 3.7 ± 2.2 mm) than those detected on MSCT.
Cal- cifications could only be detected reliably on MSCT if they were larger than 2.1 mm in
length or 36° in angle.
Half of the calcifications seen on the IVUS images cannot be detected on contrast enhanced
64- slice MSCT angiography images because of their size. The limited resolution of MSCT is the main
reason for missing small calcifications.
