Usefulness of multidetector computed tomography for the evaluation of coronary vascular lesions assessed by intravascular ultrasound

Abstract

Contrast-enhanced multidetector computed tomography (MDCT) has been used as an alternative to coronary angiography for the assessment of coronary artery disease in the intermediate risk group. Because coronary calcium is a known limiting factor for MDCT evaluation, we evaluated the accuracy of 64-channel MDCT accuracy for each coronary calcium score by comparing it with that of intravascular ultrasound (IVUS). 54 intermediate-risk subjects (Framingham point scores, 9~20) with 162 sites (worst stenosis, proximal and distal 10mm from worst stenosis) who had a suspected lesion on 64-channel MDCT before performing coronary angiography with IVUS were enrolled. External elastic membrane (EEM) cross sectional area (CSA), minimal luminal area (MLA), and stenosis area were compared between IVUS and MDCT measurements, and the population was divided into 4 groups based on coronary calcium score: group 1 (coronary calcium score, 0), group 2 (1~99), group 3 (100~399), and group 4 (>400). Within each of the 4 groups, correlations for plaque area were close (r=0.671, r=0.623, r=0.562, r=0.571, respectively). Plaque character, categorized into pathologic intimal thickening, fibroatheroma, and fibrocalcific plaque, was compared to MDCT density. there was significant overlap of MDCT density values among plaque groups. These results show that the intra/extra luminal CSA of MDCT are well correlated with those of IVUS despite increasing of coronary calcium score among groups. Therefore, MDCT is reliable enough for evaluation of coronary stenosis severity in the intermediate-risk group with coronary calcium. However, 64-channel MDCT currently has a limited role currently for plaque characterization and further study is needed.