QUANTITATIVE EXERCISE TC-99M TETROFOSMIN MYOCARDIAL TOMOGRAPHY FOR THE IDENTIFICATION AND LOCALIZATION OF CORONARY-ARTERY DISEASE

The aim of this study was to evaluate the accuracy of quantitative 1-d ay exercise-rest technetium-99m tetrofosmin tomography in the identifi cation of patients with coronary artery disease (CAD) and in the detec tion of individual stenosed coronary vessels. Sixty-one patients with suspected CAD who underwent coronary angiography and 13 normal volunte ers were studied. All patients were submitted to two i.v. injections o f Tc-99m-tetrofosmin, one at peak exercise (370 MBq) and the other (11 10 MBq) at rest 3 h after exercise (images 15-30 min after injection f or both studies). All patients with CAD (greater than or equal to 50% luminal stenosis) (n = 50) had an abnormal Tc-99m-tetrofosmin tomogram . Only one patient without significant coronary narrowing showed abnor mal findings. Overall sensitivity, specificity and diagnostic accuracy in the detection of individual stenosed vessels were 77%, 93% and 85% , respectively. Sensitivity and diagnostic accuracy in the identificat ion of individuals stenosed coronary vessels were significantly higher (P < 0.05) in patients with single-vessel disease (n = 21) than in th ose with multivessel disease (n = 29). Sensitivity, specificity and ac curacy for detecting individual diseased vessels were similar in patie nts without previous myocardial infarction (n = 26) and in those with previous myocardial infarction (n = 35). In myocardial territories rel ated to non-infarcted areas (n = 128), sensitivity and specificity in the detection of stenosed vessels were 70% and 95%, respectively. In i nfarcted areas (n = 55), sensitivity and specificity in the detection of stenosed vessels were 85% (P = NS vs non-infarcted areas) and 75% ( P < 0.05 vs non-infarcted areas), respectively. Finally, sensitivity w as significantly lower (P < 0.05) in vascular territories supplied by vessels with moderate stenosis (50%-75%) than in those supplied by ves sels with severe stenosis (> 75%). The results of this study demonstra te that quantitative 1-day exercise-rest Tc-99m-tetrofosmin single-pho ton emission tomographic imaging is a suitable and accurate technique to identify patients with CAD and to detect individual stenosed corona ry vessels.