Normal myocardial native T1 values in children using single-point saturation recovery and modified look-locker inversion recovery (MOLLI)

Background T-1 mapping is useful to quantify diffuse myocardial processes such as fibrosis, edema, storage disorders, or hemochromatosis. Normal pediatric myocardial T-1 values are scarce using modified Look-Locker inversion recovery (MOLLI) sequences and unavailable using Smart1Map, a single-point saturation recovery sequence that measures true T-1. Purpose/Hypothesis To establish normal pediatric myocardial T-1 values by Smart1Map and to compare them with T-1 by MOLLI. Study Type Prospective cohort study. Subjects Thirty-four children and adolescents aged 8-18 years (14 males) without cardiovascular or inflammatory diseases. Field Strength/Sequences 1.5T, MOLLI, Smart1Map. Assessment Mean T-1 values of the left ventricular myocardium, the interventricular septum, and the blood pool were measured with MOLLI and Smart1Map in basal, mid-ventricular, and apical short axis slices. Statistical Tests T-1 values were compared between locations and methods by paired samples t-tests, Wilcoxon signed ranks test, repeated-measures analysis of variance (ANOVA), or Friedman's test. Pearson's correlation coefficient was calculated. For interobserver variability, intraclass correlation coefficients and coefficients of variation were calculated, and Bland-Altman analyses were performed. Results T-1 values were longer by Smart1Map than by MOLLI in all measured locations (myocardium: 1191-1221 vs. 990-1042 msec; all P < 0.001). T-1 in basal vs. mid-ventricular slices differed both by MOLLI and by Smart1Map for myocardium and for blood (all P < 0.001). Myocardial T-1 did not correlate with age, heart rate, right or left ventricular ejection fraction (all P > 0.05) by either method. Septal vs. total myocardial T-1 values in each slice did not differ by MOLLI (basal P = 0.371; mid-ventricular P = 0.08; apical P = 0.378) nor by Smart1Map (basal P = 0.056; mid-ventricular P = 0.918; apical P = 0. 392), after artifacts had been carefully excluded. Data Conclusion We established pediatric normal native T-1 values using the Smart1Map sequence and compared the results with T-1 mapping with MOLLI. Septal T-1 values did not differ from total myocardial T-1 values in each of the myocardial slices. Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019.