Normative Data for Myocardial Native T1 and Extracellular Volume Fraction in Children

Purpose To establish normative data for myocardial T1, including extracellular volume (ECV) fraction, in healthy children. Materials and Methods In this retrospective, single-center study, T1 mapping data were collected from 48 healthy pediatric patients (14 years ± 3 [standard deviation]; range, 9–18 years; 27 of 48 [56%] male) referred for cardiac screening 1.5-T MRI between 2014 and 2017. T1 relaxometry was performed using a 5(number of heartbeats [nHB])3 modified Look-Locker inversion recovery (MOLLI) sequence, where nHB was three to five heartbeats depending on the heart rate, and was repeated 15 minutes following the administration of 0.2 mmol per kilogram of body weight of gadobenate dimeglumine, with 19 patients receiving contrast material. T1 values were calculated using a curve-fitting algorithm on average region-of-interest signal and corrected for imperfect inversion pulse efficiency. Comparisons within patients were performed with paired Student t test, between groups with unpaired Student t test or Mann-Whitney U test, and linear regression was performed to examine for associations with other variables. Results Average native T1 was 1008 msec ± 31, with a nonsignificant increase in females (1017 msec ± 27 vs 1001 msec ± 33, P = .066). Average ECV was 20.8% ± 2.4, with a nonsignificant increase in values in females (21.7% ± 1.9 vs 20.0% ± 2.6, P = .123). T1 and ECV values were increased in the septum versus the free wall. Conclusion Normative data are presented for myocardial native T1 and ECV using the MOLLI T1 mapping sequence at 1.5 T. Supplemental material is available for this article.