Normal values of native T 1 and T 2 relaxation times on 3T cardiac MR in a healthy pediatric population aged 9–18 years

Background Native myocardial T 1 and T 2 relaxation times are diagnostic tools used in clinical practice for adult and pediatric populations. Use of a mapping technique requires accurate knowledge of normal ranges in healthy patients, which is lacking in pediatric populations. Purpose To establish normal values for native T 1 and T 2 mapping in healthy pediatric subjects of different ages and sex. Study Type Prospective. Population Thirty‐eight healthy children (9–18 years; mean age 14.0 ± 2.7). Field Strength Cardiac MR with a 3T scanner. T 1 and T 2 mapping using MyoMaps software. Assessment T 1 and T 2 relaxation times were calculated from a 0.7–1.0 cm 2 region of interest placed at the mid‐ventricular short‐axis slice in the interventricular septum by two observers. Inter‐ and intraobserver variability was assessed. Statistical Tests The Student's t ‐test or the Mann–Whitney test for unpaired samples was applied to compare one continuous variable between two category groups. One‐way analysis of variance (ANOVA) or a Kruskal–Wallis test was applied to compare one continuous variable between three category groups. Correlation between two continuous variables was assessed with a Pearson or Spearman test. Results The mean native T 1 relaxation time was 1223 ± 29 msec and T 2 relaxation time was 43 ± 4.5 msec. There was no correlation between T 1 /T 2 values and age or body surface area (for T 1 P = 0.94 and 0.90 and for T 2 P = 0.19 and 0.64, respectively). There was weak correlation between T 1 values and body mass index (BMI) ( r = 0.448, P = 0.005). T 2 values were significantly higher in females compared with males (44.6 ± 4.2 vs. 40.4 ± 3.8 msec, P = 0.002). We found a significant rise of T 2 relaxation time in the pubertal period (age 13–15 years) comparing to prepubertal (age 9–12 years). Inter‐ and intraobserver agreement of T 1 ( r = 0.93; r = 0.99) and T 2 ( r = 0.96; r = 0.95) were high. Data Conclusion We report normal values of native T 1 and T 2 relaxation times obtained with Myomaps software for 3T cardiac MR in a healthy pediatric population. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:912–918.