Normal Reference Values and Determinants of Right Heart Strain Derived From MR‐Feature Tracking: A Meta‐Analysis

ABSTRACT Background A comprehensive assessment of normal reference values for right atrial (RA) and right ventricular (RV) strain derived from MR‐feature tracking (MR‐FT) is somewhat lacking. Purpose To systematically review and meta‐analyze reference values of RV and RA strain parameters using MR‐FT in healthy adults and to identify their principal determinants. Study Type Meta‐analysis. Population A total of 4228 healthy adults from 40 studies (2322 male, age range: 18–79 years). Field Strength/Sequence 1.5 and 3.0 T/balanced steady‐state free precession. Assessment A systematic search of PubMed, Embase, and Web of Science identified studies on right heart strain in healthy adults published before January 1, 2025, by two investigators. A random‐effects model aggregated RV and RA strain parameters. Subgroup and meta‐regression analyses assessed the effects of race, sex, age, FT software, MR vendor, and field strength. Statistical Tests Random‐effects model with pooled means and 95% confidence intervals, I 2 statistic, and Egger's test. p < 0.05 was considered significant. Results The pooled means of RV global longitudinal, circumferential, and radial strain (RV‐GLS, RV‐GCS, and RV‐GRS) were −22.57%, −14.16%, and 26.04%, respectively. The pooled RA reservoir, conduit, and booster strain (RA‐εs, RA‐εe, and RA‐εa) were 47.01%, 28.24%, and 18.62%, respectively. Subgroup and meta‐regression analyses identified race, sex, age, and FT software as contributing significantly to the variability in right heart measurements, while MR vendor ( p = 0.437 for RV‐GLS, 0.347 for RV‐GCS, 0.240 for RV‐GRS, 0.135 for RA‐εs, 0.162 for RA‐εe, and 0.287 for RA‐εa) and field strength ( p = 0.436 for RV‐GLS, 0.041 for RV ‐ GCS, 0.081 for RV‐GRS, 0.926 for RA‐εs, 0.377 for RA‐εe, and 0.296 for RA‐εa) had a limited impact. Date Conclusion This study provided the pooled normal values of RV and RA strain parameters in healthy adults using MR‐FT and highlighted the considerable impact of race, sex, age, and FT software on right heart strain measurements. Level of Evidence 2. Technical Efficacy Stage 5.