Myocardial T1 and T2 Mapping at 5.0 T: Feasibility and Comparison with 3.0-T MRI

Background: Myocardial T1 and T2 mapping provide a non–invasive quantitative assessment of cardiac tissue. While established at 1.5–T and 3.0–T MRI, the mapping performance and reference values at 5.0–T MRI remain to be investigated. This study aims to evaluate the feasibility and establish reference values for cardiac T1 and T2 mapping at 5.0–T MRI in healthy subjects. Methods: In this prospective study, 50 healthy volunteers underwent cardiac MRI at both 3.0–T and 5.0–T MRI systems from February to April 2025. Mapping protocols included MOdified Look Locker Inversion recovery (MOLLI, T1), T2-prepared gradient-echo (T2-prep-GRE, T2), and a simultaneous multi-parametric mapping technique (Multimap, T1 and T2). At 3.0–T MRI, both balanced steady-state free precession (bSSFP) and fast low-angle shot (FLASH) readouts were employed, while only the FLASH readout was used at 5.0–T MRI. Intra-observer, inter-observer, and scan-rescan reproducibility were assessed. Statistical analyses included coefficient of variation (CoV), intraclass correlation coefficient (ICC), and Bland-Altman analysis. Results: All techniques at 5.0–T MRI yielded high-quality, artifact-free images. Native T1 values were significantly higher at 5.0 T than at 3.0–T MRI (MOLLI: 1452.9±33.2 ms vs. 1305.9±38.3 ms, P<0.0001), while T2 values were significantly lower (T2-prep-GRE: 37.53±1.74 ms vs. 43.97±2.95 ms, P<0.0001). Scan-rescan reproducibility at 5.0 T (ICC: 0.87 – 0.92; CoV: 2.41% – 3.25%) was comparable to 3.0–T MRI. The measurement precision of 5.0 T was higher than 3.0–T MRI with FLASH readout and slightly inferior to bSSFP-based techniques. Multimap achieved efficient, simultaneous T1 and T2 quantification with acceptable reproducibility at 5.0–T MRI. Conclusion: Myocardial T1 and T2 mapping at 5.0–T MRI are reliable and reproducible in healthy individuals, offering reference values for normal myocardium at this field strength. The good measurement reproducibility and precision of 5.0–T cardiac mapping support its clinical potential for myocardial tissue characterization.