Primary Sclerosing Cholangitis and Its Mimickers: A Review of Disease and MRI Findings

Non-neoplastic cholangiopathies: an algorithmic approach

“…The symptoms are nonspecific, including cholestatic syndrome and abdominal pain. The initial signs are often limited to elevated levels of cholestatic enzymes such as alkaline phosphatase and gamma-glutamyl transferase (25) .…”

“…Biliary diverticula can also be present, and a smaller percentage of patients (8%) have biliary stones (17) , as depicted in Figure 5. Chronic involvement causes significant morphological changes in the liver, such as atrophy of the lateral segments of the left lobe and of the posterior segments of the right lobe with compensatory hypertrophy of the caudate lobe, which may be accompanied by centrally distributed regenerative macronodules (25) .…”

“…Other parasitic diseases related to recurrent pyogenic cholangitis are ascariasis and fascioliasis. It is believed that such parasitic infections can damage the ductal epithelium, particularly in the intrahepatic region, causing biliary dilatation without obstruction (25) . This can lead to bile stasis, luminal narrowing, and hepatolithiasis, which can also be caused by dietary factors or other agents, such as Escherichia coli, Schistosoma mansoni, and Helicobacter pylori.…”

“…On CT scans, the stones are hyperdense; on MRI, they have an isointense signal in T2-weighted sequences and a hyperintense signal in T1-weighted sequences. The affected segment also presents parenchymal atrophy, usually occurring in the lateral segments of the left lobe and posterior segments of the right lobe, with hypertrophy of the other segments (25) . The risk of developing cholangiocarcinoma is also increased in patients with recurrent pyogenic cholangitis, occurring in up to 5%.…”

“…The second type mentioned above results from milder arterial insufficiency, with desquamation of the epithelium, which accumulates in the lumen of the duct and can lead to biliary obstruction. The desquamated epithelium forms biliary casts within the ducts, which, like stones, are seen on MRI as hyperintense areas on T1-weighted sequences and hypointense areas on T2-weighted sequences (25,33) , as illustrated in Figure 8. In chronic cases, these first two types of involvement cause fibrosis and ductal stenosis, which can be focal or diffuse.…”