Abstract 2002: Comparison of Image Characteristics of Plaques in Culprit Coronary Arteries by 64 Slice CT and Intravascular Ultrasound in Acute Coronary Syndrome
Purpose: To evaluate characteristics of culprit coronary plaques in subjects with acute coronary syndromes (ACS), we performed 64 slice CT before invasive coronary angiogram and compared results with intravascular ultrasound (IVUS).
Materials and methods: Consecutive 22 stable subjects (18 male, 4 female, mean age 61.3±12.3 years) referred with anginal chest pain and were suspected ACS underwent emergent CT acquisition (Light Speed VCT) before IVUS. They were finally diagnosed as unstable pectoris (n=12) and acute myocardial infarction (n=10). Before coronary intervention, IVUS (TU-C200C) was performed with 40MH using an intrafocus catheter and images were obtained with 0.5mm/sec auto pullback method. Plaques in the culprit lesion were classified into
fibrotic plaques with or without spotty calcification.
Consecutive short axis images of coronary arteries were obtained by CT, and using the major branch as a landmark, location of plaques was confirmed and CT values of plaques were measured by two analyzers and compared with IVUS.
Results: Plaques in culprit lesions in ACS were diagnosed as thrombus (n=14), soft (n=4), and fibrotic (n=4) plaques by IVUS and were identified by CT in all subjects. CT values of plaques diagnosed as with thrombus (n=14) by IVUS were 46.5±24.1HU, which were higher (although not significantly) than soft plaques (n=4, 38.5±17.0HU) (P=0.37) and both of these CT values were significantly lower than those of fibrotic plaques (n=4, 86.4±26.2HU) by IVUS (all, P<0.05). Spotty calcification was observed in 10 (45.5%) in CT and all of those were superficial calcification by IVUS. Vessel positive remodeling was observed in 18 (85.7%) in CT, which was the same as with IVUS. Reproducibility of CT values among two analyzers was 0.92.
Conclusions: 64 slice CT can show plaques in culprit coronary arteries in ACS. Thrombosis and soft plaques by IVUS revealed lower CT values than fibrotic plaques by IVUS and culprit lesions of ACS tended to have spotty superficial calcification and positive remodeling confirmed by CT and IVUS. Characteristics of culprit coronary arteries in ACS may be obtained in CT, which may help to differentiate thrombi due to plaque rupture from stable non calcified plaques.