Myocardial perfusion scan accuracy in detection of coronary artery disease - Comparison with exercise stress test

In patients with coronary artery disease (CAD) noninvasive evaluation for detection of ischemia is important to avoid invasive interventions like angiography. Exercise stress test is conventionally the first study used in evaluation of CAD. Considering the noninvasive nature of the myocardial perfusion scan, we decided to compare its accuracy with stress test. Patients with chest pain, and intermediate risk for CAD underwent stress test with Bruce standard method by treadmill, and myocardial perfusion SPECT scan with Tc-99m MIBI and the results were compared to the angiography as the gold standard. Analysis of the data was performed by SPSS11.5 soft ware. The study was performed on 89 patients (mean age: 55.5, min: 29 max: 80) including 53 man and 36 women. Exercise stress test had 54% sensitivity, 65% specificity, 68% PPV, 50% NPV, while for myocardial perfusion scan sensitivity was 94%, specificity 94%, PPV 96%, and NPV 92%. Correlation between involved walls in myocardial perfusion scan with stenotic artery in angiography was 77.6%, while this value was 32.7% for exercise stress test. There was also relationship between degree of stenosis determined by angiography and severity of ischemia detected by myocardial perfusion scan. Myocardial perfusion scan is of great value in detection of CAD with sensitivity and specificity far better than exercise stress test. It is suggested that this noninvasive study being considered the first diagnostic method for patient at risk for coronary artery disease.