Normal values of native T1 and T2 relaxation times on 3T cardiac MR in a healthy pediatric population aged 9-18 years.

Abstract

Native myocardial T1 and T2 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. To establish normal values for native T1 and T2 mapping in healthy pediatric subjects of different ages and sex. Prospective. Thirty-eight healthy children (9-18 years; mean age 14.0 ± 2.7). Cardiac MR with a 3T scanner. T1 and T2 mapping using MyoMaps software. T1 and T2 relaxation times were calculated from a 0.7-1.0 cm2 region of interest placed at the mid-ventricular short-axis slice in the interventricular septum by two observers. Inter- and intraobserver variability was assessed. 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. The mean native T1 relaxation time was 1223 ± 29 msec and T2 relaxation time was 43 ± 4.5 msec. There was no correlation between T1 /T2 values and age or body surface area (for T1 P = 0.94 and 0.90 and for T2 P = 0.19 and 0.64, respectively). There was weak correlation between T1 values and body mass index (BMI) (r = 0.448, P = 0.005). T2 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 T2 relaxation time in the pubertal period (age 13-15 years) comparing to prepubertal (age 9-12 years). Inter- and intraobserver agreement of T1 (r = 0.93; r = 0.99) and T2 (r = 0.96; r = 0.95) were high. We report normal values of native T1 and T2 relaxation times obtained with Myomaps software for 3T cardiac MR in a healthy pediatric population. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:912-918.