Although [1-11C]acetate has been validated as a PET tracer for myocardial oxygen consumption (MVO2) in animals and humans, mono- and biexponential fitting of the tissue time-activity curve yields only estimates of MVO2. This study attempts to develop and validate a simple tracer kinetic model in vivo for estimation of regional MVO2.
Methods: Twenty-seven experiments were performed in 12 anesthetized dogs with [1-11C]acetate and serial PET images under different MBF and MVO2 (baseline, ischemia, xylazine, dobutamine and dipyridamole). Estimates of MVO2 were obtained from dynamic [1-11C]acetate PET and model fitting. MBF was measured by radiolabeled microspheres, and MVO2 was calculated by the Fick method using arterial and coronary blood samples.
Results: The proposed model fitted equally well for all study conditions with a multiple correlation coefficient of 0.985 +/- 0.026. Estimated MVO2 correlated linearly with measured MVO2 (y = 0.033 + 0.690x, r = 0.92, s.e. of estimates = 0.020).
Conclusion: This study indicates that MVO2 can be assessed with PET and [1-11C]acetate over a wide range with a simple tracer kinetic model.