What imaging modalities are available to help diagnose cholangicarcinoma?
A transabdominal ultrasound is useful, but usually cannot visualize the tumor itself. It may, however, visualize the tumor’s effects on bile duct obstruction (i.e. bile duct dilation). Note that in peripheral and hilar cholangiocarcinoma, distal bile ducts will not be dilated. Rarely, metastatic liver lesions may be visualized. Another common imaging modality is CT scan, where the tumor usually appears hypovascular and hypodense or isodense to the hepatic parenchyma. This is useful to differentiate cholangiocarcinoma from the more hypervascular hepatocellular carcinoma. Also, lymphadenopathy can be easily assessed. MRI is slightly superior to CT scan for tumor visualization. It can be combined with an MRCP to safely evaluate ductal architecture without exposing patients to radiation. Unfortunately, therapy requires ERCP. Endoscopic ultrasound (EUS) is very useful for imaging parts of the hepatobiliary tree. The precision of EUS in diagnosing cholangiocarcinoma remains to be completely
