Objective：To observe the 99mTc-MIBI myocardial perfusion images in patients with myocardial infarction before/after percutaneous coronary intervention (PCI),so as to screen for the reliable predictors for the therapeutic effect of PCI.Methods:Forty-eight patients with myocardial infarction receiving PCI were included in this study.The rest,stress and nitroglycerin myocardial perfusion imaging tests were performed before PCI.The stress and rest myocardial perfusion imaging tests were repeated 1-2 weeks after PCI.The value of（rest 99mTc-MIBI imaging in myocardial perfusion scores after PCI-stress 99mTc-MIBI imaging in myocardial perfusion scores before PCI）/ stress 99mTc-MIBI imaging in myocardial perfusion scores before PCI was taken as the curative effect of PCI; the value of（rest 99mTc-MIBI imaging in myocardial perfusion scores before PCI-stress 99mTc-MIBI imaging in myocardial perfusion scores before PCI）/ stress 99mTc-MIBI imaging in myocardial perfusion scores before PCI was taken as the functional viable myocardium; the value of (stress 99mTc-MIBI imaging in myocardial perfusion scores before PCI-nitroglycer 99mTc-MIBI imaging in myocardial perfusion scores before PCI）/ stress 99mTc-MIBI imaging in myocardial perfusion scores before PCI was taken as potential functional viable myocardium; and the value of（rest 99mTc-MIBI imaging in myocardial perfusion scores before PCI-nitroglycer 99mTc-MIBI imaging in myocardial perfusion scores before PCI）/ rest 99mTc-MIBI imaging in myocardial perfusion scores before PCI was taken as drug relative viable myocardium. To screen the proper predictors for therapeutic effects, linear correlation analysis was performed between the curative effect of PCI and the latter 3 factors.Results:Stress and rest myocardial perfusion defects were significantly improved after PCI (P<0.01).Correlation analysis showed that the curative effect of PCI was correlated with the latter 3 factors,with the correlation coefficients being r1=0.63,P<0.01,r2=0.94,P<0.000 1,and r3=0.92,P<0.000 1,respectively,indicating that the potential functional viable myocardium had the best correlationship with PCI.Conclusion: It is necessary to perform the rest,stress and nitroglycerin myocardial perfusion imaging tests in patients with cardiac infarction.The functional viable myocardium is a reliable index in screening the patients suitable for PCI and in predication of the therapeutic effect.