Diagnostic accuracy of noninvasive myocardial imaging for coronary artery disease: An electrocardiographic and angiographic correlation

From 1972 through 1975, a total of 781 noninvasive myocardial imaging studies were performed at rest and with exercise in 345 patients with use of potassium-43 or rubidium-81, or both. Resultant images were interpreted by three observers unaware of the clinical data. One hundred sixty of these patients underwent coronary angiography and were arbitrarily classified on the basis of percent narrowing of luminal diameter into those with coronary arterial obstruction of 70 percent or greater (hemodynamically significant disease) or less than 70 percent obstruction (insignificant disease) for the purposes of determining sensitivity and specificity of noninvasive myocardial imaging. Fifty-one of the 62 patients with angiographically insignificant coronary artery disease had normal imaging studies (specificity 82 percent). The 98 patients with angiographically significant coronary artery disease had 81 abnormal imaging studies (sensitivity 83 percent). When patients with myocardial infarction were excluded, the sensitivity rate of myocardial imaging was 75 percent, whereas that of standard electrocardiographic exercise tolerance testing was 72 percent. The sensitivity rate in identifying angiographic coronary stenosis in noninfarcted vascular beds was 88 percent when the results of myocardial imaging and electrocardiographic exercise testing were combined. These data present a standard for comparing future techniques of myocardial imaging at rest and with exercise.