Abstract
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Objectives 11C-acetate PET imaging has been used to quantify myocardial oxidative metabolism and efficiency in patients with heart failure (HF). However, the test re-test reproducibility of 11C-acetate imaging in humans has not been studied. We aimed to evaluate the reproducibility of this approach in this relevant population.
Methods 19 patients (65±9 years, 14 male) with stable HF (NYHA class 2-3; EF=35±10%) underwent 11C-acetate PET imaging at baseline and 6 weeks follow-up (47±22 days). Cardiac Echo and anthropometric data was collected at both time points. PET images were analyzed using FlowQuant© software. Mono-exponential and one-compartment models were used to obtain Kmono and k[JR1] 2 values for the left ventricle (LV) at global (whole heart) and regional levels (3 vascular territories). The work metabolic index (WMI) was calculated as Echo-derived Stroke Volume Index X Systolic BP/Kmono. Interclass correlation (ICC) and Bland-Altman analyses were used to assess reproducibility of k2 and Kmono between the two time points. Intra-observer reproducibility was also examined.
Results Kmono global LV ICC was 0.54. Kmono regional ICC was 0.69, 0.65, and 0.36 for LAD, LCx and RCA coronary artery regions, respectively. k2 global LV ICC was 0.63. k2 regional ICCs were 0.73 , 0.64, 0.47 for LAD, LCx, RCA regions. Bland-Altman reproducibility coefficient was 43% for Kmono and 33% for k2. The WMI ICC was 0.91. Intra-observer ICC was > 0.95 for all measured regions.
Conclusions Myocardial oxidative metabolism measured using 11C-acetate PET can be assessed with good to very-good reproducibility using mono-exponential fitting and compartment modeling. The WMI provides excellent reproducibility and should be considered when applying 11C-acetate PET imaging for the assessment of cardiac efficiency in heart failure.