Clinical features and MRI progression of small duct primary sclerosing cholangitis (PSC)

First, to evaluate and describe the clinical and MRI progression of patients with small duct primary sclerosing cholangitis (sdPSC), and second, to look for MRI features associated with disease progression to large duct PSC.

16 patients (7 female, 9 male; median age 27 years) with diagnosis of sdPSC and available MR imaging were included in this retrospective dual-center study. Liver function tests (LFTs) and imaging was reviewed in consensus by two radiologists at baseline and follow-up, and compared by means of non-parametric tests, with p < 0.05 deemed significant.

At baseline and follow-up patients had a cholestatic liver profile with elevated LFTs. Progressive liver deformity, heterogeneous enhancement and hilar lymphadenopathy were common findings. In 9 patients follow-up MRI was available with a mean interval between imaging of 10.6 years (range 3.6-15.3 years). 5 patients (55.5 %) developed cholangiographic changes diagnostic of large duct PSC. No correlation was observed between MRI findings or LFTs at baseline and the endpoint of developing PSC typical cholangiographic changes at follow-up imaging (p > 0.05).

More than half of sdPSC patients developed cholangiographic changes, supporting that sdPSC may be an early stage of large duct PSC rather than an entity of its own. Larger studies are needed to address the value of MRI for prediction of sdPSC disease progression.