The development and validation of magnetic resonance elastography for fibrosis staging in primary sclerosing cholangitis

ObjectivesTo develop and internally validate MR elastography (MRE) quantified liver stiffness (LS) cut-off values for distinguishing early/moderate fibrosis from cirrhosis in primary sclerosing cholangitis (PSC) against non-invasive fibrosis test of vibration-controlled transient elastography (VCTE).MethodsSixty-seven patients were enrolled prospectively at a tertiary care centre to undergo MRE and VCTE. MRE-quantified LS was calculated using three region-of-interest (ROI) methods: Trace, Average and Maximum. Each ROI method was compared with the reference standard of VCTE. Internal validation was performed with bootstrapping. Univariable and multivariable linear regression determined independent predictors for MRE-quantified LS and final Mayo Risk Score (MRS).ResultsMRE-quantified LS by Trace ROI method had the highest sensitivity [87.5%; 95% confidence interval (CI), 66.0-96.8] and specificity (96.1%; 95%CI, 89.6-99.0) for distinguishing cirrhosis; and was the strongest predictor of final MRS (, 0.44; 95% CI, 0.27-0.61). Alkaline phosphatase twice the normal upper limit (, 1.55; 95% CI, 0.95-2.17), abnormal bilirubin (, 1.27; 95% CI, 0.41-2.14) and thrombocytopaenia (, 0.79; 95% CI, 0.12-1.46) were independent predictors of LS.ConclusionsMRE has a higher correlation with MRS than VCTE; and though MRE is possibly influenced by severe cholestasis and portal hypertension, MRE-quantified LS is an independent predictor of worse MRS.Key Points center dot MRE is valid and reliable in assessing cirrhosis in PSC, and MRE-quantified Liver stiffness (LS) score was the strongest predictor of final Mayo Risk Score (MRS).center dot Trace ROI performs best for distinguishing moderate fibrosis from cirrhosis and has the highest correlation with Mayo Risk Score (MRS).center dot Cholestasis, hyperbilirubinaemia and portal hypertension may influence MRE LS score.