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). Methods: We enrolled 83 consecutive patients with coronary artery disease who underwent rest-pharmacologic stress ¹³N-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.