COMBINED HYPERINSULINEMIC GLUCOSE CLAMP AND ORAL ACIPIMOX FOR OPTIMIZING METABOLIC CONDITIONS DURING F-18 FLUORODEOXYGLUCOSE GATED PET CARDIAC IMAGING - COMPARATIVE RESULTS

To obtain optimal image quality in myocardial viability studies, it is recommended that F-18-fluordeoxyglucose (F-18-FDG) studies be perform ed with hyperinsulinaemic glucose clamping. F-18-FDG imaging after ora l administration of acipimox, a nicotinic acid derivative, results in comparable image quality to clamping. Twenty consecutive patients (7 w ith diabetes mellitus) with angiographically confirmed coronary artery disease and similar demographic/clinical profiles were randomly alloc ated to gated cardiac F-18-FDG-PET with a standard euglycaemic hyperin sulinaemic clamp protocol or using a combination of oral administratio n of acipimox and the insulin clamp technique. The image quality, expr essed as the myocardial-to-blood pool activity ratio, was superior in the combined protocol compared with the insulin clamping technique alo ne (3.37 +/- 1.46 vs 2.27 +/- 0.62, P = 0.037). Although there were no significant differences in plasma insulin and free fatty acids concen trations between the two protocols, plasma glucose concentrations obta ined with the standard protocol were elevated compared with the combin ed protocol (11.1 +/- 3.7 vs 6.3 +/- 3.0 mM during clamping; 10.2 +/- 3.3 vs 5.5 +/- 3.0 mM during acquisition). We conclude that gated F-18 -FDG-PET imaging after oral administration of acipimox plus insulin cl amping yields image quality superior to that obtained with clamping al one. ((C) 1998 Lippincott Williams & Wilkins).