Prospective Evaluation of 18F-Fluorodeoxyglucose Uptake in Postischemic Myocardium by Simultaneous Positron Emission Tomography/Magnetic Resonance Imaging as a Prognostic Marker of Functional Outcome

Background The immune system orchestrates the repair of infarcted myocardium. Imaging of the cellular inflammatory response by F-18-fluorodeoxyglucose (F-18-FDG) positron emission tomography/magnetic resonance imaging in the heart has been demonstrated in preclinical and clinical studies. However, the clinical relevance of post-MI F-18-FDG uptake in the heart has not been elucidated. The objective of this study was to explore the value of F-18-FDG positron emission tomography/magnetic resonance imaging in patients after acute myocardial infarction as a biosignal for left ventricular functional outcome. Methods and Results We prospectively enrolled 49 patients with ST-segment-elevation myocardial infarction and performed F-18-FDG positron emission tomography/magnetic resonance imaging 5 days after percutaneous coronary intervention and follow-up cardiac magnetic resonance imaging after 6 to 9 months. In a subset of patients, Tc-99m-sestamibi single-photon emission computed tomography was performed with tracer injection before revascularization. Cellular innate immune response was analyzed at multiple time points. Segmental comparison of F-18-FDG-uptake and late gadolinium enhancement showed substantial overlap (=0.66), whereas quantitative analysis demonstrated that F-18-FDG extent exceeded late gadolinium enhancement extent (33.216.2% left ventricular myocardium versus 20.4 +/- 10.6% left ventricular myocardium, P<0.0001) and corresponded to the area at risk (r=0.87, P<0.0001). The peripheral blood count of CD14(high)/CD16(+) monocytes correlated with the infarction size and F-18-FDG signal extent (r=0.53, P<0.002 and r=0.42, P<0.02, respectively). F-18-FDG uptake in the infarcted myocardium was highest in areas with transmural scar, and the standardized uptake value(mean) was associated with left ventricular functional outcome independent of infarct size ( ejection fraction: P<0.04, end-diastolic volume: P<0.02, end-systolic volume: P<0.005). Conclusions In this study, the intensity of F-18-FDG uptake in the myocardium after acute myocardial infarction correlated inversely with functional outcome at 6 months. Thus, F-18-FDG uptake in infarcted myocardium may represent a novel biosignal of myocardial injury.