Imaging of the biliary tree

While abdominal imaging can be useful in the diagnosis of cholangiocarcinoma, direct imaging of the bile ducts is often necessary. Endoscopic retrograde cholangiopancreatography (ERCP), an endoscopic procedure performed by a gastroenterologist or specially trained surgeon, has been widely used for this purpose. Although ERCP is an invasive procedure with attendant risks, its advantages include the ability to obtain biopsies and to place stents or perform other interventions to relieve biliary obstruction.^[4] Endoscopic ultrasound can also be performed at the time of ERCP and may increase the accuracy of the biopsy and yield information on lymph node invasion and operability.^[46] As an alternative to ERCP, percutaneous transhepatic cholangiography (PTC) may be utilized. Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive alternative to ERCP.^[47][48][49] Some authors have suggested that MRCP should supplant ERCP in the diagnosis of biliary cancers, as it may more accurately define the tumor and avoids the risks of ERCP.^[50][51][52]