COMPARTMENT MODEL FOR MEASURING MYOCARDIAL OXYGEN-CONSUMPTION USING [1-C-11]ACETATE

Although [1-C-11]acetate has been validated as a PET tracer for myocar dial oxygen consumption (MVO2) in animals and humans, mono- and biexpo nential fitting of the tissue time-activity curve yields only estimate s of MVO2. This study attempts to develop and validate a siple tracer kinetic model in vivo for estimation of regional MVO2. Methods: Twenty -seven experiments were performed in 12 anesthetized dogs with [1-C-11 ]acetate and serial PET images under different MBF and MVO2 (baseline, ischemia, xylazine, dobutamine and dipyridamole). Estimates of MVO2 w ere obtained from dynamic [1-C-11]acetate PET and model fitting, MBF w as measured by radiolabeled microspheres, and MVO2 was calculated by t he Fick method using arterial and coronary blood samples. Results: The proposed model fitted equally well for all study conditions with a mu ltiple correlation coefficient of 0.985 +/- 0.026. Estimated MVO2 corr elated 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-C-11]acetate over a wide range with a sim ple tracer kinetic model.