[Usefulness of 18F-fluorodeoxyglucose positron emission tomography for evaluating myocardial viability in old myocardial infarction].

The purpose of this study is to compare the characteristics of images obtained by positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) in the fasted state (> 6 hours) and in the glucose-loaded state (oral 50 g glucose load). In the both condition FDG-PET were performed in 18 cases with old myocardial infarction. PET images in the fasted state were divided into 2 groups (Group A; 12 cases and Group B; 6 cases). FDG uptake of normal region was visually absent (grade 0) in group A, whereas it was visually apparent (grade 1-3) in group B. Serum free fatty acid in group B was significantly lower than that in group A. In the 7 cases, the relation between myocardial FDG uptake of the infarcted regions and reversibility after coronary intervention was studied. Both in the fasted and in the glucose-loaded state, postoperative improvement was observed in the segments, in which myocardial uptake of FDG were visually apparent (glucose-loaded state, 11/13 segments; fasted state, 6/8 segments). Therefore FDG-PET images appeared to be useful for evaluating myocardial viability.