Cardiac T1ρ Mapping Values Affected by Age and Sex in a Healthy Chinese Cohort

Background: To facilitate the clinical use of cardiac T1 rho, it is important to understand the impact of age and sex on T1 rho values of the myocardium.Purpose: To investigate the impact of age and gender on myocardial T1 rho values.Study Type: Cross-sectional.Population: Two hundred ten healthy Han Chinese volunteers without cardiovascular risk factors (85 males, mean age 34.4 +/- 12.5 years; 125 females, mean age 37.9 +/- 14.8 years).Field Strength/Sequence: 1.5 T; T1 rho-prepared steady-state free precession (T1 rho mapping) sequence.Assessment: Basal, mid, and apical short-axis left ventricular T1 rho maps were acquired. T1 rho maps acquired with spin-lock frequencies of 5 and 400 Hz were subtracted to create a myocardial fibrosis index (mFI) map. T1 rho and mFI values across different age decades, sex, and slice locations were compared.Statistical Tests: Shapiro-Wilk test, Student's t test, Mann-Whitney U test, linear regression analysis, one-way analysis of variance and intraclass correlation coefficient. Significance: P value <0.05.Results: Women had significantly higher T1 rho and mFI values than men (50.3 +/- 2.0 msec vs. 47.7 +/- 2.4 msec and 4.7 +/- 1.0 msec vs. 4.3 +/- 1.1 msec, respectively). Additionally, in males and females combined, there was a significant positive but weak correlation between T1 rho values and age (r = 0.27), while no correlation was observed between the mFI values and age (P = 0.969).Data Conclusion: We report potential reference values for cardiac T1 rho by sex, age distribution, and slice location in a Chinese population. T1 rho was significantly correlated with age and sex, while mFI was only associated with sex.