cholangiographic

x-ray examination of the bile ducts, using a radiopaque dye as a contrast medium. In the intravenous method, the dye is administered intravenously and is excreted by the liver into the bile ducts. X-ray films are taken at 10-minute intervals as the dye is excreted via the cystic, hepatic, and common bile ducts into the intestinal tract. The excretion is usually completed within 4 hours. Preparation of the patient for the intravenous method requires restriction of fluids to concentrate the dye and may also include cleansing of the intestinal tract on the day prior to the examination with a laxative or enema so that fecal material and gas will not obscure the biliary tract.

Sometimes cholangiography is done after surgery of the gallbladder and biliary tract. In this method the radiopaque dye is injected directly into a tube that has been left in the biliary tract since the time of surgery. Films are taken immediately after the dye is injected. If no obstruction is present, the biliary structures fill readily and rapidly empty into the intestinal tract.

When it is necessary for the surgeon to locate gallstones or other obstructive conditions at the time that surgery is being performed, the dye may be injected directly into the bile ducts. Films are taken in the operating room, and obstructions not otherwise discernible can be located and corrected while the patient is still anesthetized.

A patient who is jaundiced cannot undergo either intravenous cholangiography or oral cholecystography. An alternative route for the injection of the contrast dye and visualization of the biliary system is percutaneous transhepatic cholangiography. Under fluoroscopic control, a needle is introduced through the skin and into the liver where the contrast material is deposited. Obstructed and distended bile ducts can then be visualized. After visualization the ducts can be drained via the needle.