Hepatobiliary Scan
A hepatobiliary scan (HIDA scan), also called a cholescintigraphy, is an imaging test used to diagnose problems in the hepatobiliary tract, the region that includes the liver, gallbladder and bile ducts. During the scan, a radioactive tracer is injected into the patient's arm to replicate the pathway bile takes in the body. A machine called a nuclear medicine scanner then tracks the tracer as it moves from the liver, where bile is produced, into the gallbladder, where bile is stored, and then into the small intestine, where bile aids in the digestion of fats. Imaging and data are recorded on a computer for future analysis.
Reasons for a HIDA Scan
Most frequently, a HIDA scan is performed to evaluate gallbladder function, but is also used to track the flow of bile from the liver to the small intestine. This test is normally performed in conjunction with other diagnostic tests, such as X-rays and an ultrasound scan of the region. Conditions that may be diagnosed by a HIDA scan include:
- Congenital abnormalities of the bile ducts
- Cholecystitis (inflammation of the gallbladder)
- Bile leaks
- Fistulas
A HIDA scan may also be performed to evaluate post-surgical complications or in order to assess the function of a liver transplant.
The HIDA Scan Procedure
Before a HIDA scan, the patient must fast for at least 4 hours, but may be permitted to drink clear liquids. The physician may advise the patient to stop certain medications temporarily so that they do not interfere with the results of the test. While normally the tracer is infused or injected, there are situations in which a patient is asked to take the medication a few days prior to the scan.
During the procedure, the patient lies on a table while the radioactive tracer is administered intravenously. The patient may experience a feeling of pressure while being injected. From above, a gamma camera takes pictures as the radioactive tracer passes through the hepatobiliary tract.
The HIDA scan takes approximately an hour. Occasionally, some images will have to be retaken due to lack of clarity in the originals. Sometimes a medication known as CCK is administered to assist in observation of gallbladder contractions. The most difficult part of the HIDA scan for most patients is that they have to hold still for the length of the test.
Risks of a HIDA Scan
Although the risk from the small of amount of radioactive tracer injected is small, HIDA scans are not performed on pregnant women or nursing mothers because of possible harm to the fetus. The radiation emitted from the tracer only lasts for a few hours. The substance then decays and any residual tracer is excreted through the urine during the next few days. Although there may be some bruising or soreness at the site of the injection, the only risk to the patient involves an allergic reaction to the radioactive material. Sure reactions are rare and usually mild.
For more information about Hepatobiliary Scan, Call Arash Padidar's office at 408-918-0405