Effect of age and sex on cardiac magnetic resonance native T1 mapping and synthetic extracellular volume.

Background Cardiac magnetic resonance (CMR) using native T1 mapping and extracellular volume (ECV) fraction is the gold standard for noninvasive detection of diffuse myocardial fibrosis. Previous studies indicate that women tend to have higher native T1 and ECV values than men, but how these parameters evolve with cardiac aging remains unclear. Methods And Results Relations between age, sex, and native T1 and synthetic ECV were assessed in 306 individuals (mean age 45 ± 18 years; 47.4 % women) free of structural cardiac disease undergoing clinically indicated CMR imaging on a 1.5 Tesla scanner. Woman had significantly higher T1 values (1025 ± 38.1 versus 1000.5 ± 33.3 ms, p < 0.001) and ECV (27.9 ± 3.3 versus 25.3 ± 3.1 %, p < 0.001) compared to men. While T1 values and ECV decreased with age in women, an opposing age-effect was observed in men (p = 0.042 and p = 0.009 for women vs men, respectively). In adjusted models, age and female sex were significantly associated with higher native T1 and ECV values (p < 0.05), while the interaction term for female sex*age showed an inverse relationship with both parameters (p < 0.001). ECV, but not native T1 relaxation times, was significantly influenced by left ventricular end diastolic volume (LVEDV, p < 0.001) and LV mass (p = 0.015), with larger LV volumes and lower LV mass correlating with higher ECV values. Conclusion This CMR study demonstrates that native T1 and ECV are influenced not only by sex and age, but also by their interaction, as well as by cardiac chamber size and heart rate. These factors should be jointly considered when interpreting myocardial tissue parameters in older individuals.