Backgound ; Fluorine-18 Fluorodeoxyglucose positron emission tomography is a tool of choice measuring viability of infarct related myocardium. Objective : The objective of this study is to study the correlation of coronary flow velocity profile in the LAD measured by transthoracic Doppler echocardiography that were obtained at 2days and 5days after primary percutaneous intervention (PCI) and area of nonviable myocardium by F-18 FDG PET in patient with anterior STEMI. Method : 20 patients who had their first anterior STEMI and were successfully reperfused by primary PCI were enrolled this study. Measuring coronary flow velocity profile and coronary flow reserve (CFR) by adenosine were performed at 2 and 5 days after Primary PCI, respectively. Myocardial viability in the LAD region was measured by F-18 FDG PET at 14 days after Primary PCI. In F-18 FDG PET study, non-viable myocardium was defined as below 40% of maximal FDG uptake in the non-infarcted myocardium. Result : Area of non-viable myocardium (% of LV) quantified by PET were not correlated with diastolic deceleration time (DDT; r=-0.404, p=0.077) and diastolic deceleration rate (DDR; r=0.201, p=0.395) at 2 days after reperfusion, However, DDT (r=-0.646, p=0.004) and DDR (r=0.749, p<0.001) at 5days after reperfusion significantly correlated with area of non-viable myocardium. CFR at both 2 and 5 days after PCI did not show significant correlation with non viable myocardium. Conclusion ; DDT and DDR of LAD flow at 5 days after primary PCI were quantitatively correlated with area of nonviable myocardium. However Coronary flow velocity profile at 2 days after reperfusion did not show these correlation with myocardial viablility. There were no significant correlation of CFR and area of non-viable myocardium.