Myocardial washout kinetics of carbon-11 labelled acetate ([11C]acetate) by positron emission tomography (PET) closely correlate with myocardial oxygen consumption (MVO2). Analysis of the tissue time activity curve by conventional monoexponential curve fitting, however, does not account for spillover effects and recirculating 11C activity. In theory, a compartment model considering variations of the arterial input function and metabolic 11C contamination, could improve consistency of MVO2 estimations. The objective of the study was to investigate this hypothesis.
Nineteen healthy volunteers were studied under resting conditions with [11C]acetate PET. Time activity curves were analysed by automated monoexponential curve fitting and a single-tissue compartment model to obtain Kmono and k2, as noninvasive indices of MVO2. Subsequently, Kmono and k2 were related to the rate-pressure product, as an indirect marker of MVO2.
The rate-pressure product was significantly correlated to Kmono (r=0.46, P=0.047) and k2 (r=0.75, P<0.001).
The results of this study suggest that a single-tissue compartment model yields more accurate noninvasive estimates of MVO2 by the use of [11C]acetate PET in humans, in comparison with monoexponential curve fitting.
2011. Vol. 32, no 1, 59-62 p.