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A cholangiography is a medical procedure done to visualize the biliary tree or the bile ducts. The biliary tree is the structure through which the bile, which is produced in the liver, passes before going to the intestines to digest fats taken during a meal. This test usually involves the use of a special dye injected in the patient's bile ducts and followed by a series of X-rays. It is often done to examine the area for blockage and narrowing, which can result in cholangitis, or bile duct inflammation. Symptoms of cholangitis are fever, pain in the abdomen, skin yellowing, and liver enlargement.
There are several types of cholangiography. These include percutaneous transhepatic cholangiography (PTC), endoscopic retrograde cholangiopancreatography (ERCP), and postoperative cholangiography. They usually differ in the process of how dye is being introduced into the biliary tree.
For instance, in PTC, a long needle is injected in the abdomen to place the dye in the biliary tree. In ERCP, an endoscope, which is a flexible tube with camera attached at the end, is usually inserted in the patient's mouth until it reaches the first part of the small intestines. Through this, a thin tube or catheter is then inserted in the bile ducts followed by injection of the dye in the area. Patients who undergo surgery for removal of the gall bladder often have a T-shaped tube inserted in the bile duct after surgery. For postoperative cholangiography, the dye is introduced through this T-shaped tube.
After the introduction of dye into the biliary tree of the patient, a series of X-rays are then taken. The X-ray films are then read by a radiologist, a doctor who is an expert in interpreting imaging tests results. When there is no blockage, the dye usually flows continuously. Its absence in any section of the biliary tree often indicates obstruction. Causes of bile duct obstruction include cysts, tumors, or cancer in the area and bile duct stones, among others.
Before undergoing the procedure, patients are usually instructed to fast for at least eight hours. They may also be sedated during the process. The whole procedure usually takes about 30 minutes to one hour. Results of the test are often released two to three days later.
There are some risks involved in cholangiography. These include pain at the site of injection and bleeding that can manifest as bloody stools. The use of the special dye may also be toxic to the kidneys. Other side effects from cholangiography include vomiting, dry mouth, blurring of vision, and severe allergic reactions.