Quantifying the Area at Risk in Reperfused ST-Segment–Elevation Myocardial Infarction Patients Using Hybrid Cardiac Positron Emission Tomography–Magnetic Resonance Imaging

Background—Hybrid positron emission tomography and magnetic resonance allows the advantages of magnetic resonance in tissue characterizing the myocardium to be combined with the unique metabolic insights of positron emission tomography. We hypothesized that the area of reduced myocardial glucose uptake would closely match the area at risk delineated by T2 mapping in ST-segment–elevation myocardial infarction patients. Methods and Results—Hybrid positron emission tomography and magnetic resonance using 18F-fluorodeoxyglucose (FDG) for glucose uptake was performed in 21 ST-segment–elevation myocardial infarction patients at a median of 5 days. Follow-up scans were performed in a subset of patients 12 months later. The area of reduced FDG uptake was significantly larger than the infarct size quantified by late gadolinium enhancement (37.2±11.6% versus 22.3±11.7%; P<0.001) and closely matched the area at risk by T2 mapping (37.2±11.6% versus 36.3±12.2%; P=0.10, R=0.98, bias 0.9±4.4%). On the follow-up scans, ...