BACKGROUND: Thalium 201(TI-201) has been a widely applied myocardial perfusion agent for the detection of coronary artery disease. however its low emission energy and long half-life make this agent suboptiomal for the examination of coronary artery disease. To circumvent the physical limitation of TI-201, a group of technetium 99m-labeled isonitril complex has been developed. Our study was done to examine the value of SPECT with 99mTc-HexaMIBI in estimating myocardial perfusion in patients with myocardial infarction. METHODS: We evaluated the sensitivity of SPECT with 99mTc-HexaMIBI in 29 patients with acute myocardial infarction. We also compared the severity and vascular territory of abnormal perfusion on SPECT scanning with severity of coronary artery stenosis, values of serum enzyme and sites in ECG. RESULTS: 1) There were 26 patients(90%) who showed perfusion defect, and 3 patients(10%) who showed normal perfusion in myocardial SPECT. The 3 patients with normal perfusion demonstrated non Q-wave infarction of ECG. 2) Among 23 patients performed coronary argiography, there were 19 patients(82%) who showed positive findings on myocardial SPECT and luminal narrowing above 50% on coronary angiogram, and there were 3 patients(13%) who showed significant coronary artery stenosis in spite of negative myocardial SPECT. 3) The grade of perfusion defect showed no significant difference between groups undergone thrombolytic therapy and groups not undergone thrombolytic therapy. 4) There was good correlation between the site of perfusion defect on SPECT and the site of infarction on ECG. CONCLUSION: We conclude that SPECT with 99mTc-HexaMIBI is a promising non invasive test for simultaneous diagnosis of myocardial infarction and evaluation of perfusion defect.