Relationship between Coronary Artery Calcium Score by Multidetector Computed Tomography and Plaque Components by Virtual Histology Intravascular Ultrasound

The aim of this study was to evaluate the relationship between coronary artery calcium score (CACS) assessed by multidetector computed tomography (MDCT) and plaque components assessed by virtual histology-intravascular ultrasound (VH-IVUS) in 172 coronary artery disease (CAD) patients with 250 coronary lesions. CACS was assessed according to Agatston scoring method by MDCT and patients were divided into four groups: Group I (CACS = 0 [n = 52]); Group II (CACS = 1-100 = 99]); Group III (CACS = 101-400 [n = 84]); and Group IV (CACS > 400 [n = 15]). Total atheroma volume was greatest in Group IV (152 +/- 132 mu L vs 171 +/- 114 mu L vs 195 +/- 149 mu L vs 321 +/- 182 mu L, P < 0.001). The absolute dense calcium (DC) and necrotic core (NC) volumes were greatest, and relative DC volume was greatest in Group IV (5.5 +/- 6.6 mu L vs 11.0 +/- 10.3 mu L vs 15.6 +/- 13.6 mu L vs 36.6 18.2 mu L, P < 0.001, and 14.8 +/- 18.2 mu L vs 19.5 +/- 18.9 mu L vs 22.5 +/- 19.1 mu L vs 41.7 +/- 27.9 mu L, P < 0.001, and 6.4 +/- 5.3% vs 11.0 +/- 6.2% vs 14.0 +/- 6.5% vs 20.0 +/- 7.8%, P < 0.001, respectively). The absolute plaque and DC and NC volumes and the relative DC volume correlated positively with calcium score. CAD patients with high calcium score have more vulnerable plaque components (greater DC and NC-containing plaques) than those with low calcium score.