Abstract 347: The Detection of Non-Calcified Coronary Plaques by Dual Source Computed Tomography is Related to the Plaque Thickness
Purpose Computed tomography angiography (CTA) permits noninvasive detection and characterization of coronary atherosclerotic plaque. We studied the ability of CTA to detect coronary atherosclerotic plaque as compared to intravascular ultrasound (IVUS) in an ex-vivo setting and determined independent predictors for the detection of non-calcified plaque.
Methods Ten ex-vivo human atherosclerotic coronary arteries were imaged in a moving phantom by Dual Source CT (DSCT) and IVUS and reconstructed at co-registered cross sections every 0.4 mm. Cross sections were assessed qualitatively for the presence and composition of atherosclerotic plaque (non-calcified, mixed and calcified plaques) on DSCT and IVUS. In addition, we measured lumen area, plaque area, plaque eccentricity and intimal thickness on IVUS images.
Results In total, 1002 cross-sections were co-registered, among them 585 with non-calcified (58%), 162 with mixed (16%), and 32 with calcified plaque (3%) as assessed by IVUS. The accuracy of DSCT to detect and classify non-calcified plaques was significantly lower than for the mixed and calcified plaques (69% vs. 82% vs. 92%, respectively, p<0.05). In multivariate regression analysis, lumen area, plaque area, eccentricity and intimal thickness were all predictors (p<0.05) for the detection of non-calcified plaque, but only intimal thickness remained an independent predictor in adjusted analysis with detection rates ranging from 23% for plaques with <<26> 0.78 mm intimal thickness to 80% for plaques with > 0.78 intimal thickness
Conclusion We established the limited ability of DSCT to detect non-calcified plaque in an ex vivo setting. However, we determined plaque thickness as the only independent predictor of the ability of CTA to detect non-calcified plaque as compared to IVUS. Given knowledge from IVUS studies about the plaque characteristics in various patient populations, these results may provide a perspective for the ability of CTA to be used in plaque progression and risk prediction studies.