Feasibility of position emission tomography derived endocardial wall strain: direct comparison with magnetic resonance using hybrid 13N ammonia PETMR system

Purpose We aimed to evaluate the feasibility of positron emission tomography feature tracking (PETFT) for assessing endocardial wall strain by comparing it with cardiac magnetic resonance (CMR)-derived feature tracking (CMRFT). MethodsWe enrolled 83 consecutive patients with coronary artery disease who underwent rest-pharmacologic stress N-13-ammonia PETMR (67 males, mean age 66 years). PETFT and CMRFT were obtained through simultaneous acquisition with electrocardiography-gated PET and cine-CMR. Global longitudinal and circumferential strain (GLS and GCS) were calculated. Correlations and Bland-Altman plots were employed to evaluate associations, bias, and 95% limit of agreement (LOA) between PETFT and CMRFT. Results PETFT and CMRFT showed significant correlations (R = 0.57 [95% CI 0.41-0.70], R = 0.71 [95% CI 0.58-0.80], R = 0.59 [95% CI 0.43-0.71], and R = 0.69 [95% CI 0.56-0.79] for rest GLS, rest GCS, stress GLS, and stress GCS, respectively; p < 0.001 for all). Bland-Altman plot showed good agreements, while a systematic error was observed (LOA -10.2-8.8, -8.7-10.7, -10.5-8.5, and -9.4-12.0; bias -0.7, 1.0, -1.0, and 1.3; for rest GLS, rest GCS, stress GLS, and stress GCS; respectively). Conclusion PETFT has been identified as a feasible technique compared to CMRFT, highlighting its potential as a novel tool for assessing wall strain in routine clinical settings.