cholangiography

n. imaging of the bile ducts in order to demonstrate anatomical abnormalities, generalized diseases of the bile ducts, the presence of stones, or the site and nature of local blockages. It may be combined with imaging of the pancreatic duct (cholangiopancreatography), as in endoscopic retrograde cholangiopancreatography (see ERCP). Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive magnetic resonance imaging technique that is increasingly used as an alternative to ERCP for diagnosis, but does not allow any treatment to be performed at the same examination. In operative (or on-table) cholangiography, a radiopaque contrast medium is injected into the bile ducts during cholecystectomy, to make sure there are no stones remaining in the main ducts. Percutaneous transhepatic cholangiography (PTC) is an invasive fluoroscopic technique in which a needle is passed through the skin, across the liver, and into a bile duct; contrast material can then be injected to outline the ducts. Using a Seldinger technique, drains or stents can be placed to treat infection or malignant strictures of the ducts. T-tube cholangiography involves the postoperative injection of radiopaque contrast material via a drain left in the main bile duct after cholecystectomy.