RELATION OF CORONARY CALCIUM DETERMINED BY ELECTRON-BEAM COMPUTED-TOMOGRAPHY AND LUMEN NARROWING DETERMINED BY AUTOPSY

Coronary calcium determined by electron beam computed tomography (CT) has not been systematically evaluated regarding prediction of histopat hologic atherosclerotic disease. Furthermore, gender specificity has n ot been examined. The 3 major epicardial arteries were dissected from 13 consecutive hearts (5 women and 8 men) after autopsy. Each artery w as straightened and scanned using CT in contiguous 3 mm thick cross se ctions. After imaging, histologic sections were prepared at correspond ing intervals and luminal area obstruction determined by planimetry. E lectron beam CT scans were analyzed to determine coronary calcium area (i.e., tomographic area with CT density >130 Hounsfield units). A tot al of 522 histologic specimens were examined and paired with correspon ding CT scans (182 in women, 340 in men). Receiver-operating character istic (ROC) analysis was used to define site specificity of calcium ar ea for luminal area narrowing by atherosclerosis. ROC curve areas for segmental CT calcium and prediction of atherosclerosis representing mi ld, moderate, or severe disease were, respectively, 0.712, 0.843, and 0.857 for women and 0.732, 0.793, and 0.841 for men. Curves relating f alse-positive rate (1-specificity) to predefined degrees of atheroscle rotic narrowing versus calcium area were curvelinear. In both women an d men, calcium areas on the order of 1 mm(2)/coronary segment were nec essary to predict at least mild atherosclerosis with a false-positive rate of 0% (i.e., 100% specificity), whereas a calcium area >3 mm(2) w as necessary to predict the same result for severe disease. In conclus ion, coronary artery calcium area as determined by electron beam CT ha s the potential to predict segment histopathologic coronary disease. I ncreasing coronary calcium areas were associated with increasing likel ihood of more advanced atherosclerotic involvement, regardless of pati ent gender.