Evaluation of ECG-gated [11C]acetate PET for measuring left ventricular volumes, mass, and myocardial external efficiency

Abstract

Background: Noninvasive estimation of myocardial external efficiency (MEE) requires measurements of left ventricular (LV) oxygen consumption with [11C]acetate PET in addition to LV stroke volume and mass with cardiovascular magnetic resonance (CMR). Measuring LV geometry directly from ECG-gated [11C]acetate PET might enable MEE evaluation from a single PET scan. Therefore, we sought to establish the accuracy of measuring LV volumes, mass, and MEE directly from ECG-gated [11C]acetate PET. Methods: Thirty-five subjects with aortic valve stenosis underwent ECG-gated [11C]acetate PET and CMR. List mode PET data were rebinned into 16-bin ECG-gated uptake images before measuring LV volumes and mass using commercial software and compared to CMR. Dynamic datasets were used for calculation of mean LV oxygen consumption and MEE. Results: LV mass, volumes, and ejection fraction measured by CMR and PET correlated strongly (r = 0.86-0.92, P < .001 for all), but were underestimated by PET (P  < .001, bias −3 ± 21%, P = .56). PET-based MEE bias was strongly associated with LV wall thickness. Conclusions: Although analysis-related improvements in accuracy are recommended, LV geometry estimated from ECG-gated [11C]acetate PET correlate excellently with CMR and can indeed be used to evaluate MEE.