Differentiating pediatric autoimmune liver diseases by quantitative magnetic resonance cholangiopancreatography

Autoimmune liver diseases (AILD), including primary sclerosing cholangitis (PSC), autoimmune sclerosing cholangitis (ASC), and autoimmune hepatitis (AIH), have overlapping clinical features but distinct management strategies and outcomes. The purpose of this study was to assess the diagnostic performance of quantitative magnetic resonance cholangiopancreatography (MRCP) parameters for distinguishing PSC/ASC from AIH in children and young adults.

This IRB-approved, cross-sectional study included participants from an institutional AILD registry that underwent baseline serum liver biochemistry testing and 3D fast spin-echo MRCP. The biliary tree was extracted and modeled from MRCP images using novel proprietary software (MRCP+ ™; Perspectum Diagnostics; Oxford, United Kingdom), and quantitative parameters were generated (e.g., biliary tree volume; number and length of bile ducts, strictures, and dilations; bile duct median/maximum diameters). Mann-Whitney U tests were performed to compare laboratory values and MRCP metrics between patient cohorts (clinical diagnosis of PSC/ASC versus AIH). Receiver operating characteristic (ROC) curves and multivariable logistic regression were used to assess diagnostic performance of serum biochemistry values and MRCP parameters for discriminating PSC/ASC from AIH.

Thirty percent (14/47) of MRCP exams failed post-processing due to motion artifact. The remaining 33 patients included 20 males and 13 females, with a mean age of 15.1 ± 3.9 years. Eighteen patients were assigned the clinical diagnosis of PSC or ASC and 15 of AIH. All but one quantitative MRCP parameter were significantly different between cohorts (p < 0.05) and predictive of diagnosis (ROC p < 0.05), including numbers of bile duct strictures (area under curve [AUC] = 0.86, p < 0.0001) and dilations (AUC = 0.87, p < 0.0001) and total length of dilated ducts (AUC = 0.89, p < 0.0001). Laboratory values were not significantly different between cohorts (p > 0.05). The best multivariable model for distinguishing PSC/ASC from AIH included total length of dilated ducts (odds ratio [OR], 1.08; 95% CI 1.02-1.14) and maximum left hepatic duct diameter (OR, 1.21; 95% CI 0.57-2.56) [AUC = 0.92].

Quantitative MRCP parameters provide good discrimination of PSC/ASC from AIH.