Towards standardization of positron emission testing with computed tomography myocardial perfusion volumes and left ventricular ejection fraction: comparison with cardiac MRI

Gated positron emission testing with computed tomography (PET-CT) yields left ventricular (LV) volume analysis along with perfusion analysis. The correlation between PET-CT volumes and cardiac magnetic resonance imaging (CMR) volumes remains unknown. Understanding of the accuracy of these volumes and ejection fractions (EF) by PET is clinically relevant, particularly in the sarcoid population where patients receive initial diagnostic CMR and then are followed by PET for inflammation. 89 patients undergoing cardiac sarcoidosis evaluation with both rest PET-CT and CMR within approximately 1 year were identified at Cleveland Clinic from 2011 to 2021. LV volumes and EF were collected. Linear regression and Bland-Altman analyses were performed. Mean PET-CT derived left ventricular ejection fraction (LVEF) was 46 ± 16% with mean LV end diastolic volume (LVEDV) of 127 ± 60 mL and mean LV end systolic volume (LVESV) of 75 ± 54 mL. Mean CMR-derived LVEF was 47 ± 15% with mean LVEDV of 189 ± 61 mL and mean LVESV of 106 ± 60 mL. Pearson correlation coefficient with standard measurements was 0.85 for EF, 0.80 for LVEDV, and 0.86 for LVESV. In our cohort, there is an excellent correlation of LVEF between PET-CT and CMR with a mean difference of 1.1% and a good correlation of volumes between these two imaging modalities. This has potential clinical implications when judging LVEF qualifications for medical and device therapies although future larger validation cohorts are warranted.