Test–retest Assessment of Biventricular Myocardial Oxidative Metabolism and Perfusion in Pulmonary Hypertension Patients Using 11C-acetate PET Imaging: A Pilot Study
摘要
11C-acetate PET is used to measure biventricular oxygen myocardial consumption rate (MVO2) and myocardial blood flow (MBF) changes associated with right ventricular (RV) remodelling. We studied PET reproducibility and repeatability for such RV assessments.
Procedures10 pulmonary hypertension (PH) patients underwent 11C-acetate PET. Five of these patients also had a repeat scan after 26 ± 2 weeks. A one-tissue compartment model was used to measure the myocardial tissue-activity washout rate (k2 [1/min] for MVO2 estimation) and the blood-to-tissue activity flux (K1 [1/min] for MBF calculation). Values were measured by 2 blinded observers and analyzed by ANOVA and Bland–Altman tests. The interquartile ranges (IQR), within-subject coefficients of variation (wCV), and intraclass correlation coefficients (ICC) were reported.
ResultsAll patients had stable PH with the clinical assessments showed comparable biventricular function and size between baseline and follow-up. The k2-derived MVO2 and K1-derived MBF values were consistently higher in the LV than RV. The high inter- and intra-observer reproducibility (for biventricular MVO2 and MBF) was indicated by low IQR (≤ 7.6%) and wCV (≤ 8%) as well as high ICC (≥ 95%). The test–retest (baseline to follow-up) repeatability showed larger IQR (≤ 35.4%) and wCV (≤ 29%) but consistently high ICC (= 95%).
ConclusionsMVO2 and MBF values measured in the RV of patients with PH were highly reproducible and repeatable. This can help inform the design of clinical research studies using serial 11C-acetate PET imaging to evaluate RV metabolism.