Patient education: HIDA scan (The Basics)

What is a HIDA scan? — A HIDA scan is a type of imaging test. It creates pictures of the liver, gallbladder, and bile ducts. This test is also called "cholescintigraphy."

The gallbladder is a small, pear-shaped organ that is tucked under the liver (figure 1). It stores bile, a fluid that is made in the liver and helps the body break down fat. When you eat a meal that has fat in it, the gallbladder empties the bile into a tube called the "bile duct." The bile duct carries the bile into the small intestine to help with digestion.

For a HIDA scan, a chemical called a "radioactive tracer" is injected into 1 of your veins. It travels through your bloodstream to your liver. Then, it flows through your bile ducts to the gallbladder and small intestine, along with the bile your liver makes. A scanner with a special camera takes pictures (figure 2) so the doctor can see the flow of bile in your body.

A HIDA scan can be used to check for problems in the liver or gallbladder. It can also be used for monitoring if you have had a liver transplant or biliary stent. (A stent is a tube that is used to hold the bile duct open if it has been blocked.)

How do I prepare for a HIDA scan? — The doctor or nurse will tell you if you need to do anything special to prepare.

They will also ask you about your "health history." This involves asking you questions about any health problems you have or had in the past, past surgeries, and any medicines you take. Tell them about:

●Any medicines you are taking – This includes any prescription or "over-the-counter" medicines you use, plus any herbal supplements you take. It helps to write down and bring a list of any medicines you take, or bring a bag with all of your medicines with you.

●Any allergies you have

●Whether you are pregnant, could be pregnant, or are breastfeeding – HIDA scans are usually not done during pregnancy, because they are not safe for a developing baby.

If you are breastfeeding, you can get a HIDA scan if needed. But you will not be able to feed your baby any breast milk you make for 24 hours after the scan. You might want to plan ahead for this, for example, by pumping extra milk ahead of time.

You will also get information about:

●Eating and drinking before your procedure – You might need to "fast" before a HIDA scan. This means not eating or drinking anything for a period of time, usually at least 4 to 6 hours. You might be allowed to have clear liquids during this time.

Ask the doctor or nurse if you have questions or if there is anything you do not understand.

What happens during a HIDA scan? — When it is time for the procedure:

●You will change into a hospital gown and remove any jewelry or other accessories.

●You will get an "IV," which is a thin tube that goes into a vein.

●The person doing the HIDA scan (called a "technologist") will use your IV to inject the radioactive tracer into your vein.

●You will lie on a table. The machine with the camera will be moved so it is above your belly. The machine does not touch you. The technologist will not be in the room with you while the pictures are taken, but they will be nearby and able to see you and talk to you.

●You need to lie very still during the HIDA scan so that the images are clear. You might be asked to change your position so the camera can get different angles. You might also get other medicines through your IV.

●A HIDA scan usually takes between 1 and 2 hours, sometimes longer. This depends on how many pictures your doctor wants to see.

What happens after a HIDA scan? — The medical staff will remove your IV. In most cases, you can go home right away after your HIDA scan.

The chemical used in a HIDA scan is radioactive. For the next 1 to 2 days:

●Drink plenty of water to help your body get rid of it.

●Your body will get rid of the chemical on its own through your urine. When you use the toilet, flush twice, and wash your hands thoroughly. This to prevent other people from being exposed to the chemical.

●Because the amount of radiation is very small, you do not need to avoid being around other people.

●If you are breastfeeding, do not give your baby any breast milk you make for 24 hours after the scan. During this time, you might need to pump milk and throw it away.

What are the risks of a HIDA scan? — Your doctor will talk to you about all of the possible risks, and answer your questions. Possible risks include:

●A minor or serious allergic reaction to the chemical injected into your vein

●Radiation exposure – A HIDA scan exposes you to some radiation. In general, exposure to radiation very slightly raises a person's risk of developing cancer later in life. But the amount of radiation in a HIDA scan is very small. The overall risk increases if you have to get many imaging tests over time.

What else should I know? — You might get your results the same day, or it might take a few days or weeks for them to be read by an expert. Your doctor or nurse will let you know when to expect your results.

If your HIDA scan shows any abnormal results, your doctor or nurse will talk to you about what to do next.

More on this topic

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Patient education: Choosing surgery to treat gallstones (The Basics)

Patient education: Gallstones (Beyond the Basics)