Magnetic resonance imaging T1 mapping of the liver, pancreas and spleen in children.

Abstract

To characterize T1 relaxation times of the pancreas, liver, and spleen in children with and without abdominal pathology. This retrospective study included pediatric patients (< 18-years-old). T1 mapping was performed with a Modified Look-Locker Inversion Recovery sequence. Patients were grouped based on review of imaging reports and electronic medical records. The Kruskal-Wallis test with Dunn's multiple comparison was used to compare groups. 220 participants were included (mean age: 11.4 ± 4.2years (1.5T); 10.9 ± 4.5years (3T)). Pancreas T1 (msec) was significantly different between subgroups at 1.5T (p < 0.0001). Significant pairwise differences included: normal (median: 583; IQR: 561-654) vs. acute pancreatitis (731; 632-945; p = 0.0024), normal vs. chronic pancreatitis (700; 643-863; p = 0.0013), and normal vs. acute + chronic pancreatitis (1020; 897-1099; p < 0.0001). Pancreas T1 was also significantly different between subgroups at 3T (p < 0.0001). Significant pairwise differences included: normal (779; 753-851) vs. acute pancreatitis (1087; 910-1259; p = 0.0012), and normal vs. acute + chronic pancreatitis (1226; 1025-1367; p < 0.0001). Liver T1 was significantly different between subgroups only at 3T (p = 0.0011) with pairwise differences between normal (818, 788-819) vs. steatotic (959; 848-997; p = 0.0017) and normal vs. other liver disease (882; 831-904; p = 0.0455). Liver T1 was weakly correlated with liver fat fraction at 1.5T (r = 0.39; 0.24-0.52; p < 0.0001) and moderately correlated at 3T (r = 0.64; 0.49-0.76; p < 0.0001). There were no significant differences in splenic T1 relaxation times between subgroups. Pancreas T1 relaxation times are higher at 1.5T and 3T in children with pancreatitis and liver T1 relaxation times are higher in children with steatotic and non-steatotic chronic liver disease at 3T.