CT cholangiography (protocol)

Last revised by Joshua Yap on 10 Apr 2023

CT cholangiography is a technique of imaging the biliary tree with the usage of hepatobiliary excreted contrast. It is useful in delineating biliary anatomy, identifying a bile leak or looking for retained gallstones within the biliary system.

Second-line test (after ultrasound) when investigating for right upper quadrant pain, obstructive LFTs, etc. It can also be used in the postoperative setting (e.g. post-cholecystectomy) where there is a concern for common bile duct injury or retained gallstones, or where intraoperative cholangiography (IOC) is unable to be performed due to extensive inflammation or a narrow cystic duct, proving direct cannulation difficult.

The purpose of CT cholangiography is to identify a filling defect in the biliary tree that represents choledocholithiasis or a contrast leak from the biliary tree in case of injury. 

  • bilirubin should be <30 µmol/L nor should it be rising rapidly (as the impaired excretory ability of hepatocytes can affect contrast excretion in bile) 

  • severe hepatic or renal dysfunction

  • thyroid dysfunction

  • iodinated-contrast adverse reactions

CT cholangiography may be performed with either intravenous or oral cholangiographic contrast agents both of which outline the biliary tree with positive contrast. 

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