Investigation of [18F]2-fluoro-2-deoxyglucose for the measure of myocardial glucose metabolism.

Abstract

F-18-labeled 2-deoxyglucose (FDG) was studied as a glucose analog for the measure of myocardial glucose metabolism. Myocardial uptake and retention, blood clearance, species dependence (dog, monkey, man), and effect of diet on uptake were investigated. Normal myocardial uptake of FDG was 3–4% of infected dose in dog and monkey, and 1–4% in man, compared with brain uptakes of 1.5–3% in dog, 5–6% in monkey, and 4–8% in man. The myocardial metabolic rate (MR) for glucose in the non-fasting (glycolytic) state was 2.8 times that in the fasting (ketogenic) state. Human subjects showed higher myocardial uptake after a normal meal than after-meal containing mostly free fatty aicds (FFA). Blood clearance was rapid with initial clearance t1/2 of 0.2–0.3 min, followed by a t 1/2 of 8.4 ± 1.2 min in dog and 11.6 ± 1.1 min in man. A small third component had half-times of 59 ± 10 min and 88 ± 4 min in dog and man, respectively. With the ECAT positron tomograph, high image-contrast ratios were found between heart and blood (dog 3.5/1, man 14/1), heart and lung (dog 9/1, man 20/1), and heart and liver (dog 15/1, man 10/1). FDG was found to be taken up rapidly by the myocardium without any significant tissue clearance over a 4-hr period. FDG exhibits excellent imaging properties. Average counting rates of 12K, 20K, and 40K c/min-mCi injected are obtained in human subjects with high, medium, and low resolutions of the ECAT tomograph. Determination of glucose and FFA MR in vivo with ECT provides a method for investigation and assessment of changing aerobic and anaerobic metabolic rates in ischemic heart disease in man.