In paediatric and young adult with autoimmune liver disease AILD, multiparametric MRI (LiverMultiScan) and MRCP+ showed robust associations with laboratory markers. cT1 correlated with markers of liver disease activity, and cT1 IQR appeared less confounded than MRE. MRCP+ biliary metrics discriminated AIH from PSC/ASC, supporting combined imaging for noninvasive stratification and monitoring.