Kajinami K, Seki H, Takekoshi N, Mabuchi H
Second Department of Internal Medicine, School of Medicine, Kanazawa University, Japan.
J Am Coll Cardiol. 1995 Nov 1;26(5):1209-21. doi: 10.1016/0735-1097(95)00314-2.
This study was designed to compare the usefulness of electron beam computed tomography for prediction of coronary stenosis with that of electrocardiographic (ECG) and thallium exercise tests.
Electron beam computed tomography can quantify coronary calcifications; however, its clinical value has yet to be established.
Using the volume mode of electron beam computed tomography, we studied 251 consecutive patients who underwent elective coronary angiography because of suspected coronary artery disease and compared the results with those of ECG and thallium exercise tests. The total coronary calcification score was calculated by multiplying the area ( > or = 2 pixels) of calcification (peak density > or = 130 Hounsfield units) by an arbitrarily weighted density score (0 to 4) based on its peak density. The mean of two scans was log transformed.
Calcification was first noted in women in the 4th decade of life, approximately 10 years later than its occurrence in men. Among patients with advanced atherosclerosis (two- and three-vessel disease), calcification scores were uniformly high in women but ranged widely in men. Nine percent of patients with significant stenoses ( > or = 75% by densitometry) had no calcification. The calcification scores of patients with significant stenosis in at least one vessel were significantly higher than those of patients without significant stenosis in the study group as a whole and in most patient subgroups classified according to age and gender. A cutoff calcification score for prediction of significant stenosis, determined by receiver operating characteristic curve analysis, showed high sensitivity (0.77) and specificity (0.86) in all study patients; sensitivity was similarly high even in older patients ( > or = 70 years) and was enhanced in middle-aged patients (40 to < or = 60 years). The difference in specificity between calcification scores and ECG exercise test results had borderline significance (p = 0.058) and that between calcification scores and thallium test results was significant (p = 0.001). The latter difference became small but remained significant (p = 0.01) even after the reevaluation of thallium test results in light of each subject's clinical data.
Quantification of coronary artery calcification with electron beam computed tomography noninvasively predicted angiographically confirmed coronary stenosis. Results obtained with this method were at least as useful and potentially better in some patient groups than those obtained with thallium and ECG exercise testing.
本研究旨在比较电子束计算机断层扫描在预测冠状动脉狭窄方面与心电图（ECG）及铊运动试验的有效性。
电子束计算机断层扫描可对冠状动脉钙化进行量化；然而，其临床价值尚未确立。
我们使用电子束计算机断层扫描的容积模式，对251例因疑似冠状动脉疾病而接受择期冠状动脉造影的连续患者进行了研究，并将结果与ECG及铊运动试验的结果进行比较。通过将钙化区域（≥2像素）（峰值密度≥130亨氏单位）乘以基于其峰值密度的任意加权密度评分（0至4）来计算总的冠状动脉钙化评分。对两次扫描的平均值进行对数转换。
钙化首先在40岁的女性中被发现，比男性出现钙化的时间晚约10年。在患有晚期动脉粥样硬化（双支和三支血管病变）的患者中，女性的钙化评分普遍较高，而男性的评分范围广泛。9%的严重狭窄患者（通过密度测定法≥75%）没有钙化。在整个研究组以及根据年龄和性别分类的大多数患者亚组中，至少有一支血管存在严重狭窄的患者的钙化评分显著高于无严重狭窄的患者。通过接受者操作特征曲线分析确定的预测严重狭窄的钙化评分临界值，在所有研究患者中显示出高敏感性（0.77）和特异性（0.86）；即使在老年患者（≥70岁）中敏感性同样很高，在中年患者（40至≤60岁）中敏感性有所增强。钙化评分与ECG运动试验结果之间的特异性差异具有临界显著性（p = 0.058），钙化评分与铊试验结果之间的差异具有显著性（p = 0.001）。即使根据每个受试者的临床数据重新评估铊试验结果后，后一差异虽变小但仍具有显著性（p = 0.01）。
电子束计算机断层扫描对冠状动脉钙化的量化可无创地预测血管造影证实的冠状动脉狭窄。在某些患者组中，用这种方法获得的结果至少与铊及ECG运动试验获得的结果一样有用，且可能更好。
