Abstract
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Objectives: he aim is to evaluate myocardial oxidative metabolism in mice using carbon-11 (C11) acetate and dynamic PET. We investigated the difference in myocardial oxidative metabolism between pairs of mice with different ages or under different treatment plans. A pair of specially designed and constructed twin imaging beds was attached to the imaging table of a Sedecal SuperArgus 4R preclinical PET/CT system. The animals were anesthetized with 2.5% isoflurane before being placed on the twin beds with continuous infusion of the 2.0% isoflurane through nose cones. They were then simultaneously injected with ~700 μCi of C-11 acetate intravenously through the catheters pre-installed into the tail veins. Listmode PET data were acquired for 10 minutes followed by a 120 sec[P1] [BT2] CT scan of the animal pair. The listmode PET data were subsequently binned into blocks of 8 sec, 16 sec, 32 sec, and 64 sec dynamic frames. They were reconstructed into dynamic PET images at 33 time points and registered with the CT images. The experimental myocardial data curve and blood input data were derived from a volume-of-interest (VOI) encompassing the left ventricular wall and left ventricular chamber, respectively, in the averaged dynamic PET images. The kinetics of the C-11 acetate were analyzed using a 1-compartment model proposed by van den Hoff et al. [2001] in the PMOD kinetic modeling software. The estimates of the K1 and K2 parameters of the 1-compartment model and the blood flow estimate were obtained from the best model curve fittings to the experimental data. The extraction fraction (EF), which is proportional to the myocardial oxidative metabolism, was obtained from a ratio of K1 and blood flow. The data acquisition and analysis protocols were applied to a series of 20 pairs of animals with different ages, and treatments with Losartan, AT1, and AT2. Preliminary data analysis showed that the EF estimates from healthy animals of different ages were found to be centered at ~0.38 +/- 0.1. The Losartan and AT2 treatment did not increase EF while the AT1 treatment showed an increase to ~0.42 +/- 0.1. We concluded that the application of carbon-11 acetate and dynamic PET provide good measures of myocardial oxidative metabolism in mice using a 1-compartment kinetic model analysis. They allow investigations of changes of myocardial oxidative metabolism due to age, health condition and treatment methods. [P1]Please use “minutes” and “seconds” or “min” and “sec” [BT2] <!--EndFragment-->