In this study, we compared the accuracy of the rate of myocardial glucose use (rMGU) measured using PET and 1-(11)C-glucose with the rate measured using PET and the more conventional tracer (18)F-FDG.
Methods: PET measurements of myocardial tracer uptake (K, in mL/g/min) and rMGU (in nmol/g/min) were obtained with 1-(11)C-glucose and (18)F-FDG in 21 dogs using kinetic modeling and the Patlak graphical method, respectively. Eighteen dogs were studied during hyperinsulinemic-euglycemic clamp performed either at rest or combined with phenylephrine, dobutamine, intralipid infusion, or intralipid infusion and dobutamine. Three dogs were studied during intralipid infusion alone under resting conditions. Arterial-coronary sinus sampling was performed to measure the K of both tracers (n = 14) and rMGU by the Fick method (n = 21).
Results: PET-derived values for K from either 1-(11)C-glucose or (18)F-FDG correlated closely with directly measured tracer K values (glucose: y = 0.98x + 0.01, r = 0.79, P < 0.001; (18)F-FDG: y = 0.74x + 0.03, r = 0.77, P < 0.001). In contrast, correlation with K values of unlabeled glucose measured directly was better for 1-(11)C-glucose (y = 0.92x + 0.02, r = 0.96, P < 0.0001) than for (18)F-FDG (y = 0.66x + 0.05, r = 0.72, P < 0.01) (P < 0.001 for comparison of correlation coefficients). As a consequence, PET-derived values for rMGU correlated more closely with Fick-derived measurements of unlabeled glucose using 1-(11)C-glucose (y = 0.82x + 168, r = 0.97, P < 0.0001) than with (18)F-FDG (y = 0.81x + 278, r = 0.79, P < 0.001) (P < 0.001 for comparison of correlation coefficients).
Conclusion: Over a wide range of conditions, PET-derived measurements of rMGU are obtained more accurately with 1-(11)C-glucose than with (18)F-FDG.