Cholangiography: what é, what it is for and how é done

Cholangiography is an X-ray exam used to evaluate the bile ducts, and which allows the visualization of the bile path from the liver to the duodenum.

Often this type of test is done during surgery to remove a gallbladder stone, for example, but it can also be indicated by the doctor to help diagnose other problems related to the bile ducts, such as:

• Bile duct obstruction;
• Lesions, strictures or dilatation of the ducts;
• Gallbladder tumor.

Also, if an obstruction of the bile ducts is found, the doctor can, during the examination, remove what is causing the obstruction, causing an almost immediate improvement of symptoms.

How the exam is done

There are several types of cholangiography that can be ordered according to the doctor's suspicion. Depending on the type, the way to take the exam may be a little different:

1. Intravenous cholangiography

This method consists of administering a contrast agent into the bloodstream, which will then be eliminated by the bile. After that, images are obtained every 30 minutes, which will allow the study of the course of the contrast along the bile ducts.

2. Endoscopic cholangiography

In this technique, a probe is introduced from the mouth to the duodenum, where the contrast product is administered and then an X-ray is taken at the contrast site.

3. Intraoperative cholangiography

In this method, the examination is done during surgery to remove the gallbladder, called a cholecystectomy, in which a contrast agent is given and several X-rays are taken.

4. Magnetic resonance cholangiography

This technique is performed after gallbladder removal surgery, with the aim of evaluating the bile ducts after removal, in order to identify possible complications that may be caused by residual stones not detected during surgery.

How to prepare for the exam

Preparation for cholangiography may vary according to the type of exam, however, general precautions include:

• Fast for 6 to 12 hours;
• Drink only small sips of water up to 2 hours before the exam;
• Tell the doctor about the use of medications, especially aspirin, clopidogrel, or warfarin.

In some cases, the doctor may also order a blood test up to 2 days before the test.

Possible side effects

Although it is not very common, there are some side effects that can occur from performing this test such as damage to the bile ducts, pancreatitis, internal bleeding or infection.

After cholangiography, if symptoms such as fever above 38.5ºC or abdominal pain that does not improve, it is advisable to go to the hospital.

When the exam should not be done

Although this test is considered safe, it is not recommended for people who have hypersensitivity to contrast, infection of the biliary system or who have high levels of creatinine or urea. In these cases, the doctor may recommend performing another test to evaluate the bile ducts.