Accuracy of 64-slice multidetector computed tomography for classification and quantitation of coronary plaque: Comparison with integrated backscatter intravascular ultrasound

Background: Noninvasive assessment of coronary plaque is important for coronary risk stratification. Whereas integrated backscatter intravascular ultrasound (IB-IVUS) has proven effective for analysis of the tissue components of coronary plaque, plaque assessment by 64-slice multidetector computed tomography (MDCT) has not been established. We therefore evaluated the accuracy of MDCT compared with IB-IVUS for identification of coronary plaque components and determination of plaque volume. Methods: Thirty-one sites in 17 coronary vessels (7 left anterior descending, 5 left circumflex, and 5 right coronary arteries) with substantial stenosis were visualized by both 64-slice MDCT and IB-IVUS. Coronary plaque was evaluated by MDCT and the findings were compared with those of IB-IVUS at the same sites and for the same vessel lengths. Plaque was classified as low-attenuated, fibrous, or calcified, and the volume of each plaque component and total plaque volume were calculated. Results: Total plaque volume per vessel determined by MDCT was significantly correlated with that determined by IB-IVUS (r = 0.704, P < 0.05, n = 17). However, the volumes of individual plaque components determined by the two approaches were not correlated. The predominant plaque morphology as determined by the two approaches was consistent in 12 of the 17 vessels (70.6%), whereas calcified and low-attenuated plaques were overestimated by MDCT in the remaining vessels. Conclusions: MDCT is a promising approach for noninvasive detection of different types of coronary plaque and may therefore contribute to coronary risk stratification. The ability of MDCT to determine the volume of individual plaque components, however, is limited.