Primary Biliary Cirrhosis and Primary Sclerosing Cholangitis: an Update on MR Imaging Findings with Recent Developments
Primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC) are the most common immune-mediated chronic cholestatic liver diseases leading to cirrhosis and liver failure. Although magnetic resonance imaging (MRI) is not a necessary procedure for the diagnosis of PBC, MRI is recommended for monitoring disease progression and early detection of complications. Even though liver cirrhosis subtypes have similar MR imaging features, there are some findings which could indicate PBC, such as the periportal halo sign. Additionally, MRI using diffusion-weighted imaging with apparent diffusion coefficient measurements provides non-invasive assessment of the stage of liver fibrosis. The role of cholangiography is crucial for the diagnosis of PSC. Since endoscopic retrograde cholangiography is an invasive procedure with occasional post-procedural complications, the latest guidelines suggest magnetic resonance cholangiography as a reference procedure for evaluation of patients suspected with PSC. Characteristic magnetic resonance cholangiography findings include multiple segmental strictures with slightly dilated ducts among them, usually on both intrahepatic and extrahepatic bile ducts. Furthermore, magnetic resonance cholangiography is useful in the follow-up of these patients, allowing for timely diagnosis of complications such as cholangiocellular carcinoma. With the exception of ursodeoxycholic acid, which slows the progression of PBC, the only curative treatment for both PSC and PBC is still liver transplantation. However, recurrent disease occurs in some patients indicating the need for development of new more effective therapies.
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Abbreviations: AMA: anti-mitochondrial antibodies; ADC: apparent diffusion coefficient; CA 19-9: cancer antigen 19-9; CCC : cholangiocellular carcinoma; DWI: diffusion-weighted imaging; HCC: hepatocellular carcinoma; HLA: human leukocyte antigen; MRI: magnetic resonance imaging; PBC: primary biliary cirrhosis; PSC: primary sclerosing cholangitis; TE: transient elastography; UDCA: ursodeoxycholic acid.