Quantification of atherosclerotic coronary plaque components by submillimeter computed tomography

Background: Although several investigations have shown that multi-detecor row computed tomography (MDCT) of the coronary arteries can detect noncalcified atherosclerotic plaque, it has remained unresolved if the method also determines features of a rupture-prone plaque. We set out to correlate the size of atherosclerotic plaque components with cardiac MDCT with histology. Methods and results: In 30 autopsy cases, hearts were isolated, coronary arteries filled with contrast agent, and depicted with a clinical 16-row detector CT with a slice thickness of 0.63 mm. Transections of the three main coronary arteries were reconstructed and compared with histopathologic sections using light microscopy. MDCT measurements of total plaque area (r = 0.73, P < 0.0001) and calcified plaque area (r = 0.83, P < 0.0001) correlated well with histopathology, while measurements of non-calcified plaque area (r = 0.53, P < 0.0001) and lipid core size (r = 0.43; P < 0.0001) correlated less well. MDCT overestimated all plaque areas except lipid core size, which was underestimated. Conclusions: Coronary CT provides an accurate and reproducible method for the quantitative assessment of total plaque and calcified plaque areas. However, the method is less accurate for the quantification of non-calcified plaque area and lipid core size, which is ascribed to limited spatial and contrast resolution. With the present technique, the detection of vulnerable plaques by MDCT remains uncertain.