Background Reperfusion is the golden therapy for ST-segment elevation myocardial infarction (STEMI) in the initial12 hours after onset of symptom.However, prognosis of patients varied remarkably that could not simply be attributed to individual characteristics, discrepancy of reperfusion modalities, time to symptom onset and lesion locations.Besides its role as reference standard of functional assessment, Cardiac Magnetic Resonance (CMR) has unique advantages over other investigations regarding to its capability to directly visualize myocardial edema, intramyocardial hemorrhage and necrosis area, which leads CMR a preferring way to evaluate the efficacy of reperfusion for individual patient.Current data demonstrated out initial fmdings of early CMR examination in reperfused STEMI patients.