Left ventricular function and volumes from gated [¹³N]-ammonia positron emission tomography myocardial perfusion imaging: A prospective head-to-head comparison against CMR using a hybrid PET/MR device

Background: Positron emission tomography (PET) myocardial perfusion imaging (MPI) can be used to evaluate left ventricular (LV) volumes and function. We performed a head-to-head comparison of LV function and volumes obtained simultaneously using [¹³N]-ammonia-PET and cardiac magnetic resonance (CMR), with the latter serving as the reference standard.

Methods and results: In this prospective study, 51 patients underwent [¹³N]-ammonia-PET MPI and CMR using a hybrid PET/MR device. Left ventricular end-systolic volumes (LVESV), end-diastolic volumes (LVEDV), stroke volumes (LVSV), ejection fractions (LVEF), and segmental wall motion were analyzed for both methods and were compared using correlational and Bland-Altman (BA) analysis; segmental wall motion was compared using ANOVA. The agreement between [¹³N]-ammonia-PET and CMR for LVEF was good, with minimal bias (- .6%) and narrow BA limits of agreement (- 7.9% to 6.8%), but [¹³N]-ammonia-PET systematically underestimated LV volumes, with high bias in LVESV (- 11.2 ml), LVEDV (- 28.9 ml), and LVSV (- 17.5 ml). Mean segmental wall motion in [¹³N]-ammonia-PET differed significantly among the corresponding normokinetic (6.6 ± 2 mm), hypokinetic (5.1 ± 2 mm), and akinetic (3.3 ± 2 mm) segments in CMR (P < .01).

Conclusion: LVEF and LV wall motion can be accurately assessed using [¹³N]-ammonia-PET MPI, although LV volumes are significantly underestimated compared to CMR.