Primary sclerosing cholangitis: diagnostic performance of MRI compared to blood tests and clinical scoring systems for the evaluation of histopathological severity of disease.

Purpose: To assess the diagnostic performance of magnetic resonance imaging (MRI) compared to blood tests and clinical scoring systems for the evaluation of histopathologic severity in patients with primary sclerosing cholangitis (PSC).
Materials: Fifty-one patients (M/F 37/14, mean age 41 years) with PSC who underwent MRI and liver histopathology were included in this IRB-approved retrospective study. Two radiologists independently graded the severity of biliary abnormalities on magnetic resonance cholangiopancreatography (MRCP) using a standardized scoring system, parenchymal enhancement, and diffusion-weighted imaging (DWI) signal. Liver function tests, Mayo Risk score, APRI, FIB-4 Index, MELD, and Child-Pugh scores were recorded. Histopathology was assessed using a modified Nakanuma's scoring system. Correlation and diagnostic performance of MRI scores and blood tests for assessment of PSC histopathologic disease severity were evaluated.
Results: Findings of cirrhosis and portal hypertension were the only imaging features diagnostic of advanced PSC (stages 3 and 4) with AUC up to 0.90 (p < 0.001) for both observers. Parenchymal enhancement and overall qualitative biliary ductal abnormality identified advanced PSC stage with AUC up to 0.767 (p = 0.002) only for one observer. There was weak correlation between the overall qualitative biliary ductal abnormality on MRCP and histopathologic stage (r = 0.36, p = 0.01) for one observer. FIB-4 index, Child-Pugh, MELD, Mayo Risk, APRI, and alkaline phosphatase demonstrated good to excellent performance for advanced PSC stage (AUCs 0.672-0.915, p < 0.045).
Conclusions: MRI findings of cirrhosis/portal hypertension, blood tests, and clinical scoring systems had high performance for advanced histopathologic PSC stage diagnosis, while the severity of biliary abnormalities on MRI did not.