Reference Ranges for Myocardial Native T1, T2, and Extracellular Volume at 5.0T Cardiac MRI in Healthy Adults

Background 5.0 T Cardiovascular Magnetic Resonance (CMR) offers potential advantages over 3.0 T systems, including improved signal-to-noise ratio and spatial resolution. Although myocardial T1 and T2 mapping techniques are increasingly applied in clinical practice, reference ranges for these parameters at 5.0 T have not yet been established. The aim of this study is to determine normal reference values for myocardial native T1, T2 relaxation times, and extracellular volume (ECV) in healthy adults using 5.0 T CMR. Methods This prospective study enrolled 181 healthy Chinese adults aged 20 to 80 years who underwent 5.0 T CMR. T1 and T2 mapping of the left ventricle were performed using a motion-corrected modified Look-Locker inversion recovery sequence and a T2-prepared single-shot sequence, respectively. Global and segmental myocardial T1, T2, and ECV values were quantified. Associations with sex, age, body mass index (BMI), and myocardial thickness were analyzed. Results The mean global myocardial T1, T2, and ECV values were 1496 ± 37ms, 35 ± 3ms and 27 ± 2%, respectively. Females showed significantly higher T1 and T2 values than males (T1: 1509 ± 35ms vs 1483 ± 35ms, p <.001; T2: 36 ± 2ms vs 34 ± 2ms, p <.001). No significant age-related differences were observed. T1, T2, and ECV values were inversely associated with BMI (T1: r =-0.16, p =.034; T2: r =-0.35, p <.001; ECV: r =-0.31, p =.015). T1 values positively correlated with myocardial thickness ( r =0.19, p <.001), whereas T2 and ECV values negatively correlated with thickness ( r =-0.21 and -0.19, respectively; both p <.001). Segmental analysis showed lower T1 but higher T2 and ECV values at the apex compared with the mid and basal myocardium (all p <.001). Conclusion This study establishes normative myocardial T1, T2, and ECV values at 5.0 T CMR in healthy adults. Myocardial tissue characteristics were influenced by sex, BMI, and myocardial thickness, with regional variations observed across myocardial segments.