Gallbladder Scan

Test Overview

A gallbladder scan is a nuclear scanning test that is done to evaluate gallbladder function. It can detect blockage in the tubes (bile ducts) that lead from the liver to the gallbladder and small intestine (duodenum). See an illustration of the gallbladder and the duodenum .

During a gallbladder scan, a radioactive tracer substance is injected into a vein in the arm. The liver removes the tracer from the bloodstream and adds it to the bile that normally flows through the bile ducts to the gallbladder. The gallbladder then releases the tracer into the beginning of the small intestine. A special camera (gamma) takes pictures of the tracer as it moves through the liver, bile ducts, gallbladder, and small intestine.

Why It Is Done

A gallbladder scan is done to:

• Help determine the cause of pain in the upper right side of the abdomen.
• Evaluate the function of the gallbladder. A gallbladder ultrasound may be done before a gallbladder scan to help detect structural problems in the gallbladder. If the ultrasound is normal, a gallbladder scan often is done to evaluate gallbladder function.
• Help determine the cause of jaundice.
• Detect blockage of the tubes (bile ducts) leading from the liver to the gallbladder and small intestine (duodenum).

How To Prepare

Before your gallbladder scan, tell your doctor if:

• You are or might be pregnant.
• You are breast-feeding. Use formula (discard your breast milk) for 1 to 2 days after the scan until the radioactive tracer has been eliminated from your body.
• Within the past 4 days, you have had an X-ray test using barium contrast material (such as a barium enema) or have taken a medication (such as Pepto-Bismol) that contains bismuth. Barium and bismuth can interfere with test results.

Do not eat or drink for 4 to 12 hours before a gallbladder scan. Your doctor will tell you how long depending on what the test is being done for.

You may be asked to sign a consent form before the test. Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?).

How It Is Done

A gallbladder scan is usually done by a nuclear medicine technologist. The scan pictures are usually interpreted by a radiologist or nuclear medicine specialist.

You will need to remove any jewelry that might interfere with the scan. You may need to take off all or most of your clothes, depending on which area is being examined (you may be allowed to keep on your underwear if it does not interfere with the test). You will be given a cloth or paper covering to use during the test.

The technologist cleans the site on your arm where the radioactive tracer will be injected. A small amount of the radioactive tracer is then injected.

You will lie on your back on a table and a large scanning camera will be positioned closely above your abdomen. After the radioactive tracer is injected, the camera will scan for radiation released by the tracer and produce pictures as the tracer passes through your liver and into your gallbladder and small intestine. The first pictures will be taken immediately after the injection, and then about every 5 to 10 minutes for up to the next 1½ hours. Each scan takes only a few minutes. You need to lie very still during each scan to avoid blurring the pictures. The camera does not produce any radiation, so you are not exposed to any additional radiation while the scan is being done.

A substance (cholecystokinin) that stimulates the gallbladder may also be injected into your vein during the scans. The pictures taken after this injection can help determine whether the gallbladder is functioning normally. Computer analysis of the data may be used to evaluate gallbladder function. You may be asked to answer questions about your reaction to the cholecystokinin. Occasionally medication (morphine sulfate) is given to help diagnose inflammation of the gallbladder.

Depending upon your results, additional scans may be taken up to a day later. If you need to return for another gallbladder scan, you should not eat any fatty foods before you return.

The gallbladder scan takes about 1 to 2 hours.

How It Feels

You may feel nothing at all from the needle puncture when the tracer is injected, or you may feel a brief sting or pinch as the needle goes through the skin. Otherwise, a gallbladder scan is usually painless. You may find it difficult to remain still during the scan. Ask for a pillow or blanket to make yourself as comfortable as possible before the scan begins.

The test may be uncomfortable if you are having abdominal pain. Try to relax by breathing slowly and deeply.

If cholecystokinin is used during the test, it may cause nausea or abdominal pain. The development of these symptoms during the test may indicate a problem with your gallbladder. The technologist may ask you about changes in your pain during the test.

Risks

Allergic reactions to the radioactive tracer are rare. Most of the tracer will be eliminated from your body (through your urine or stool) within a day, so be sure to promptly flush the toilet and thoroughly wash your hands with soap and water. The amount of radiation is so small that it is not a risk for people to come in contact with you following the test.

Occasionally, some soreness or swelling may develop at the injection site. These symptoms can usually be relieved by applying moist, warm compresses to your arm.

There is always a slight risk of damage to cells or tissue from being exposed to any radiation, including the low level of radiation released by the radioactive tracer used for this test.

Results

A gallbladder scan is a special nuclear scanning test that is done to evaluate gallbladder function. The results of a gallbladder scan are available in 2 days.

What Affects the Test

Factors that can interfere with your test and the accuracy of the results include:

• Pregnancy. A gallbladder scan is not usually done during pregnancy because the radiation could damage the developing baby (fetus).
• Barium and bismuth. If a gallbladder scan is needed, it should be done before any tests that use barium (such as a barium enema).
• The inability to remain still during the test.
• Being allergic to morphine.

What To Think About

• A gallbladder ultrasound test may also be done to detect problems of the gallbladder. The ultrasound test provides more information about the shape and size of the gallbladder than a nuclear scan does. However, the nuclear scan can provide information about how well the gallbladder is functioning and whether the bile ducts are blocked. For more information, see the medical test Abdominal Ultrasound.
• The results of a gallbladder scan should be interpreted along with your symptoms and the results of other tests, such as a physical examination and an ultrasound. Abnormal results from a gallbladder scan do not necessarily mean that the gallbladder needs to be removed.
• A test called endoscopic retrograde cholangiopancreatogram (ERCP) can be done to detect blockage of the bile duct. For more information, see the medical test Endoscopic Retrograde Cholangiopancreatogram (ERCP).
• A magnetic resonance imaging (MRI) method called MR cholangiopancreatogram (MRCP) may also be done to detect blockage of the bile duct.

References

Other Works Consulted

• Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.

• Pagana KD, Pagana TJ (2006). Mosby’s Manual of Diagnostic and Laboratory Tests, 3rd ed. St. Louis: Mosby.

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