Repeatable and reproducible measurements of myocardial oxidative metabolism, blood flow and external efficiency using {sup 11}C-acetate PET

Background: Non-invasive approaches to investigate myocardial efficiency can help track the progression of heart failure (HF). This study evaluates the repeatability and reproducibility of {sup 11}C-acetate positron emission tomography (PET) imaging of oxidative metabolism. Methods and results: Dynamic {sup 11}C-acetate PET scans were performed at baseline and followup (47 ± 22 days apart) in 20 patients with stable HF with reduced ejection fraction. Two observers blinded to patients’ clinical data used FlowQuant{sup ®} to evaluate test–retest repeatability, as well as intra- and inter-observer reproducibility of {sup 11}C-acetate tracer uptake and clearance rates, for the measurement of myocardial oxygen consumption (MVO{sub 2}), myocardial external efficiency (MEE), work metabolic index (WMI), and myocardial blood flow. Reproducibility and repeatability were evaluated using intra-class-correlation (ICC) and Bland–Altman coefficient-of-repeatability (CR). Test–retest correlations and repeatability were better for MEE and WMI compared to MVO{sub 2}. All intra- and inter-observer correlations were excellent (ICC = 0.95-0.99) and the reproducibility values (CR = 3%-6%) were significantly lower than the test–retest repeatability values (22%-54%, P