Characterization of a highly effective preparation for suppression of myocardial glucose utilization.

Background: With appropriate protocols, F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) can visualize myocardial inflammation. Optimal protocols and normative myocardial FDG uptake values are not well-established.

Methods: We evaluated 111 patients referred for inflammation cardiac FDG PET/CT. Patients followed a low-carbohydrate, high-fat diet for 36 hours before imaging and received unfractionated heparin. Glucose and fatty acid metabolism biomarkers were obtained. Mean blood pool and maximum myocardial uptake (SUV, SUV) were measured, avoiding areas of abnormal FDG uptake or spillover.

Results: Adequate suppression of myocardial FDG uptake occurred in 95% of patients (n = 106). Myocardial SUV was significantly below background blood pool SUV: septal myocardial to blood pool ratio 0.75 (95% CI 0.73-0.77; P < 0.001); lateral myocardial to blood pool ratio 0.70 (95% CI 0.68-0.72; P < 0.001). Glucose, insulin, and C-peptide correlated to blood pool SUV (Spearman r = 0.39, P < 0.01; r = 0.40, P < 0.01; r = 0.35, P < 0.01) and myocardial SUV (Spearman r = 0.31, P < 0.01; r = 0.31, P < 0.01; r = 0.26, P < 0.01). Fatty acid metabolism biomarkers did not correlate to myocardial SUV.

Conclusions: Patients following intensive metabolic preparation have myocardial FDG SUV below background SUV. Biomarkers of glucose metabolism modestly correlate to FDG uptake.