Staging cholangiocarcinoma by imaging studies.

Cholangiocarcinoma (CCA) is an adenocarcinoma that arises from the bile duct epithelium and is observed in the entire biliary tree (intrahepatic, hilum, and extrahepatic distal). The staging of this tumor differs depending on location. The role of imaging in the staging of hilar CCA is to assess the extent of ductal involvement by the tumor, hepatic artery, or portal venous involvement, the functional status and volumetric assessment of the underlying liver, and the regional or distant tumor extension. Complete assessment is done by combining magnetic resonance (MR) cholangiography and multidetector computed tomography (CT). Multidetector CT, in particular, is accurate for resectability and the negative predictive value (patients with disease classified as unresectable and in whom unresectability has been confirmed) is quite high: 85-100%. The role of imaging in the staging of intrahepatic CCA is to evaluate resectability based on the tumor itself, vascular involvement, regional and distal extension, and volumetric assessment of the contralateral liver, and to determine the prognostic factors. These factors are mainly: tumor size, the presence of satellite nodules, vascular involvement, and lymph nodes. CT and MR imaging (MRI) are keys and their results are comparable. In distal extrahepatic CCA due to tumor location, staging is focused mainly on the adjacent vessels (portal vein and hepatic artery), the hepatoduodenal ligament, the proximal and distal biliary extent, and pancreatic invasion. CT and MRI are mandatory.