CLINICAL INVESTIGATIONS Myocardial Glucose Utilization and Optimization of 18F-FDG PET Imaging in Patients with Non– Insulin-Dependent Diabetes Mellitus, Coronary Artery Disease, and Left Ventricular Dysfunction

In patients with non–insulin-dependent diabetes mellitus (NIDDM), FDG PET imaging is often problematic because of poor uptake of FDG. Different protocols have been used; how-ever, these have not been directly compared in patients with NIDDM who have both coronary artery disease (CAD) and se-vere left ventricular (LV) dysfunction, for which defining viability is most relevant. The aim of this study was to better define the optimal means of FDG PET imaging, assessed by image quality and myocardial glucose utilization rate (rMGU), among 3 imag-ing protocols in patients with NIDDM, CAD, and severe LV dysfunction. Methods: Ten patients with NIDDM, CAD, and severe LV dysfunction (mean ejection fraction, 29.8 % 7.1%) underwent dynamic FDG PET scanning using 3 different proto-cols: the standard protocol, consisting of oral glucose loading or a supplemental insulin bolus based on fasting glucose; the niacin protocol, consisting of pretreatment with niacin to lower free fatty acids; and the insulin clamp protocol, consisting of hyperinsulinemic euglycemic clamp. Image quality was satis-factory with at least 1 approach in 8 patients, who formed the primary analysis group. Results: Myocardium–to–blood-pool ratios were significantly higher with the insulin clamp (standard