CORRELATION BETWEEN MYOCARDIAL BLOOD-FLOW AND FASTING GLUCOSE-METABOLISM IN ISCHEMIC-HEART-DISEASE - QUANTITATIVE ASSESSMENT BY N-13 AMMONIA AND F-18 FLUORODEOXYGLUCOSE POSITRON-EMISSION-TOMOGRAPHY

Ischemic myocardium avidly incorporates fluorine-18 fluorodeoxyglucose (F-18 FDG) in the fasting state, in contrast to the relative absence of F-18 FDG uptake in normal myocardium with sufficient blood flow in the fasting state. Although many studies have attempted to use F-18 FD G uptake to discriminate ischemic but viable myocardium from scarred m yocardium, little is known clinically about the correlation between bl ood flow and F-18 FDG uptake in ischemic myocardium. We studied the cr itical level of blood flow that causes avid F-18 FDG uptake in myocard ium in 9 patients. All patients had angiographically proven ischemic h eart disease but no diabetes. Regional myocardial blood flow (RMBF) wa s measured quantitatively by positron emission tomography (PET) using nitrogen-13 ammonia in the resting state, in which the normal value wa s 80.2 +/- 13.0 ml/min/100 cm(3). The F-18 FDG uptake in myocardium wa s assessed with the differential uptake ratio (DUR) scale. We construc ted circumferential profiles of radioactivity uptake in myocardium for each study, and chose 780 sections of myocardium in which the relatio n between the two factors could be analyzed. In moderately ischemic to normal myocardium with RMBF of 50 to 90 ml/min/100 cm(3), RMBF and F- 18 FDG uptake were negatively correlated (r = -0.44, p < 0.01). When R MBF was 50 to 60 ml/min/100 cm(3) (n = 121), the peak DUR value of F-1 8 FDG uptake was 4.0 +/- 2.0. The two factors were not correlated when RMBF was less than 50 ml/min/100 cm(3) or 90 ml/min/100 cm(3) or high er. Our results suggest that RMBF and F-18 FDG uptake values as measur ed with PET may provide valuable information on the possible benefit o f intervention in ischemic heart disease.