Relationship between magnetic resonance imaging spleen T1 relaxation and other radiologic and clinical biomarkers of liver fibrosis in children and young adults with autoimmune liver disease.

Background: Little is known about the relationships between MRI splenic T1 relaxation measurements and other radiologic and clinical markers of chronic liver disease, including the presence of radiologic portal hypertension.

Objective: To evaluate the relationships between MRI splenic T1 relaxation and other radiologic and clinical biomarkers of liver fibrosis, including the presence of radiologic portal hypertension, in children and young adults with autoimmune liver diseases (AILD).

Materials And Methods: Research MRI examinations performed at 1.5 T from 63 AILD registry participants were identified. Spleen T1 and iron-corrected T1 (cT1) relaxation measurements, liver cT1, liver/spleen stiffness, splenic length percentile for age, and presence of radiologic portal hypertension were recorded, along with demographic and laboratory data. The Mann-Whitney U test was used to compare continuous data between groups; Spearman correlation was used to evaluate associations. Areas-under-the-receiver operating characteristic curve (AuROC) was used to assess diagnostic performance.

Results: Mean age was 15.2 ± 4.1 years. Mean splenic T1 and cT1 values for the study population were 1158.0 ± 70.9 ms and 1436.0 ± 68.9 ms, respectively. Splenic T1 and cT1 values positively correlated with APRI and FIBROSIS-4 scores, splenic length percentile, liver cT1 values, and liver and spleen stiffnesses (p-values < 0.05). There was no significant relationship between splenic T1/cT1 and age (p-values > 0.05). Splenic T1 and cT1 values were higher in participants with vs. without radiologic portal hypertension (n = 18) (1213.4 ± 69.6 vs. 1135.4 ± 58.5 ms; p = 0.0001, and 1488.2 ± 64.8 vs. 1415.1 ± 59.1 ms; p = 0.0002). Splenic T1 and cT1 both demonstrated an AuROC of 0.81 for discriminating patients without and with portal hypertension (p-values < 0.0001).

Conclusion: Splenic T1 relaxation is associated with other radiologic and clinical biomarkers of liver fibrosis, including radiologic portal hypertension, in children and young adults with AILD.