Diagnostic Ability of Tc-99m MIBI SPECT in Coronary Artery Diseases is not Affected by the Degree of Exercise

Lee, Jaetae; Kim, Jong Soo; Chun, Kyung Ah; Lee, Sang Woo; Kang, Do Young; Cho, Yong Keun; Chae, Shung Chull; Lee, Kyu Bo

Abstract

PURPOSE: The sensitivity of ST-depression in the electrocardiogram during exercise is influenced by the level of efforts. However, unlike the prevalence of ST-depression on exercise ECG, the degree of exercise is reported to do not influence the diagnostic ability of myocardial perfusion scan. Furthermore, the relation between the prevalence of myocardial ischemia and effort is still controversial. We evaluated the effect of the degree of exercise on the ability of SPECT imaging to detect coronary artery stenosis.
MATERIALS AND METHODS
The patient population was comprised of 111 patients (73 men and 38 women, mean age 56 years) who underwent an exercise test in conjunction with Tc-99m MIBI and cardiac catheterization within 3 months apart each other. The degree of exercies was classified into four groups according to the percentage of maximal predicted heart rate. The sensitivity and specificity was compared between each group.
RESULTS
The overall diagnostic sensitivity was significantly higher with Tc-99m MIBI SPECT than exercise ECG. The specificity was not significantly different between two tests. Sensitivity and specificity of Tc-99m MIBI was not different between four groups. Sensitivity for individual coronary stenosis seemed to be lower in subjects who had premature termination of exercise due to early appearance of ST depression.
CONCLUSION
These
RESULTS
suggest that the overall diagnostic sensitivity of Tc-99m MIBI myocardial perfusion SPECT is not significantly affected by the degree of exercise in stable patients undergoing symptom-limited treadmill exercise testing. Myocardial perfusion SPECT imaging should be added to routine exercise stress testing for the detection of coronary artery disease.