Purpose : The perfusion state of specific coronary artery territories of the myocardial SPECT might be affected by many factors. Some of those factors would not be altered by coronary intervention, such as presence of fixed defect or breast shadowing and so on. We assessed the hypothesis that the diagnostic values of SPECT to detect restenosis after coronary stenting in asymptomatic patients would be affected by the accuracy of pre-intervention SPECT. Methods : One hundred thirty nine patients(173 coronary territories) were prospectively enrolled and they underwent pre-intervention SPECT, clinical follow-up and SPECT/ coronary angiography (CAG) at 6 months. Results : After excluding 11 follow-up losses, overall restenosis rate was 26%. Of the patients with typical angina (n=36), 52.8% had restenosis. In asymptomatic patients, if the corresponding myocardial territories of the coronary lesions showed fixed defects the specificity of the SPECT was extremely low(23%), and if the myocardial territories showed no perfusion decrease in pre-intervention SPECT, the sensitivity was extremely low(17%)(table 1). Conclusion: In asymptomatic patients, the diagnostic values to detect restenosis were significantly affected by the accuracy of pre-intervention SPECT. If the patients���s pre-intervention SPECT showed false negative results or fixed defects, SPECT would not be a useful tool to detect restenosis.