Atherosclerotic Plaque Composition and Classification Identified by Coronary CT: Assessment of CT-generated Plaque Maps Compared with VH-IVUS and Histology.
1University of Cambridge and Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom.
-Computed tomography is used routinely for coronary angiography and higher-risk features of plaques can also be identified. However, the ability of CT to discriminate individual plaque components and classify plaques according to accepted histological definitions is unknown.
METHODS AND RESULTS:
-We first determined CT attenuation ranges for individual plaque components using combined in vivo CT co-registered with virtual histology intravascular ultrasound (VH-IVUS) in 108 plaques from 57 patients. Comparison with contrast attenuation created plaque/contrast attenuation ratios that were significantly different for each component. In a separate validation cohort of 47 patients, these “Plaque Maps” correlated significantly with VH-IVUS-determined plaque component volumes (necrotic core (r=0.41, p=0.002), fibrous plaque (r=0.54, p<0.001), calcified plaque (r=0.59, p<0.001), total plaque (r=0.62, p<0.001)). We also assessed VH-IVUS and CT Plaque Maps against co-registered histology in 72 (VH-IVUS) and 87 (CT) segments from 8 post-mortem coronary arteries. The diagnostic accuracy of CT to detect calcified plaque (83% vs. 92%), necrotic core (80% vs. 65%) and fibroatheroma (80% vs. 79%) was comparable to VH-IVUS. However, while VH-IVUS could identify thin-cap fibroatheromas (TCFA) with a diagnostic accuracy of between 74-82% (depending on the TCFA definition used), the spatial resolution of CT prevented direct identification of TCFA.
-CT-derived Plaque Maps based on contrast-adjusted attenuation ranges can define individual plaque components with a similar accuracy to VH-IVUS ex vivo. However, coronary CT Plaque Maps could not reliably classify plaques and identify TCFA, such that high-risk plaques may be misclassified or overlooked.
- [PubMed – as supplied by publisher]