Hepatobiliary Iminodiacetic Acid (HIDA) Scan

A HIDA scan is a nuclear medicine test that uses a small amount of radioactive material to evaluate the function and structure of the liver, gallbladder, and bile ducts.

What is the purpose of a HIDA scan?

The primary purposes of a HIDA scan are:

• To assess the function of the gallbladder and its ability to contract and release bile
• To evaluate the patency of the bile ducts and identify any blockages or obstruction
• To diagnose conditions such as cholecystitis (inflammation of the gallbladder), biliary dyskinesia (abnormal movement of the gallbladder), and sphincter of Oddi dysfunction
• To monitor the effectiveness of treatment for certain liver and bile duct disorders

How is a HIDA scan performed?

The procedure typically involves the following steps:

1. The patient is injected with a small amount of radioactive material, usually technetium-99m mebrofenin or technetium-99m disofenin, which is taken up by the liver and excreted into the bile
2. The patient lies on a table and a gamma camera is positioned over the abdomen to detect the radiation emitted by the radioactive material
3. Images are taken at regular intervals, usually every 5-10 minutes, for 30-60 minutes to evaluate the uptake and excretion of the radioactive material by the liver and gallbladder
4. In some cases, additional images may be taken after the patient has eaten a fatty meal or received a medication that stimulates the gallbladder to contract

What are the different types of HIDA scans?

There are several variations of the HIDA scan, including:

• Standard HIDA scan: This is the most common type of HIDA scan and evaluates the function of the liver, gallbladder, and bile ducts
• Delayed HIDA scan: This type of scan is used to evaluate the gallbladder's ability to contract and release bile over a longer period of time, usually 2-4 hours after injection of the radioactive material
• Eat-stimulated HIDA scan: This type of scan is used to evaluate the gallbladder's response to food and assess its ability to contract and release bile in response to a fatty meal
• Cholecystokinin-stimulated HIDA scan: This type of scan uses a medication that stimulates the gallbladder to contract, allowing for evaluation of its function and assessment of any blockages or obstruction in the bile ducts

Risks and side effects

The risks and side effects associated with a HIDA scan are generally minimal and may include:

• Allergic reactions to the radioactive material
• Nausea or vomiting
• Headache or dizziness
• Radiation exposure, although this is typically very low

Preparation and aftercare

To prepare for a HIDA scan:

• Fasting may be required for several hours before the test
• Certain medications may need to be discontinued before the test
• Pregnant or breastfeeding women should inform their doctor before undergoing the test

After the test:

• The patient can usually resume normal activities immediately after the test
• The radioactive material is typically excreted from the body within 24 hours
• The results of the test are usually available within 1-2 days and will be discussed with the patient's doctor