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Hepatobiliary scan

What is a Hepatobiliary Scan?

A hepatobiliary scan (also called a HIDA scan) is a specialized imaging test that evaluates the function of your liver, gallbladder, bile ducts, and the flow of bile. This test helps diagnose various conditions affecting your biliary system, which is responsible for producing, storing, and releasing bile—a fluid that helps digest fats.

The scan uses a small amount of radioactive tracer that is processed by your liver and follows the same path that bile normally takes through your biliary system. A special camera tracks this tracer, allowing doctors to see how well your liver, bile ducts, and gallbladder are functioning.

Why Might I Need a Hepatobiliary Scan?

Your doctor may recommend this scan to:

  • Diagnose inflammation of the gallbladder (cholecystitis)
  • Detect gallbladder blockages or gallstones
  • Evaluate bile duct obstructions
  • Assess gallbladder function and ejection fraction (how well it contracts and empties)
  • Identify bile leaks after surgery or injury
  • Diagnose biliary atresia (a congenital condition in infants where bile ducts are absent or blocked)
  • Investigate causes of upper abdominal pain, especially after meals

How Does a Hepatobiliary Scan Work?

The scan works by:

  1. A radioactive tracer is injected into your bloodstream
  2. The tracer is taken up by liver cells and excreted into the bile
  3. The bile, containing the tracer, flows through the bile ducts and may collect in the gallbladder
  4. When the gallbladder contracts, the bile with the tracer flows into the intestine
  5. A special camera (gamma camera) detects the tracer’s movement, creating images of this entire process
  6. The images show how quickly and efficiently bile moves through your system

Preparing for Your Scan

  • You will need to fast for 4-12 hours before the scan (typically overnight)
  • Do not eat or drink anything except small sips of water
  • Inform your doctor about all medications you’re taking
  • Your doctor may ask you to avoid certain medications before the test, including:
    • Pain medications containing opioids
    • Certain cholesterol medications
    • Some hormonal medications
  • Tell your doctor if you:
    • Are pregnant or breastfeeding
    • Have allergies to any medications
    • Have had recent barium studies or nuclear medicine tests
    • Have recently had an imaging test using contrast material

What to Expect During the Procedure

Initial Imaging Phase

  1. You’ll lie on an examination table
  2. A small IV line will be placed in a vein in your arm
  3. The radioactive tracer will be injected through this IV
  4. Immediately after the injection, the gamma camera will begin taking pictures
  5. The camera will take continuous images for approximately 1 hour
  6. You’ll need to lie still during this time

Extended Imaging (If Needed)

If your gallbladder isn’t visible during the initial imaging:

  1. You may receive a small dose of morphine to help concentrate bile in the gallbladder
    • The morphine is given through your IV
    • It may cause mild drowsiness or nausea, but serious side effects are rare
    • If you’re allergic to morphine, alternative approaches will be used
  2. If morphine is not used or you’re allergic to it:
    • Imaging will continue hourly for up to 4 hours
    • This longer imaging time helps determine if your gallbladder is functioning slowly

Gallbladder Ejection Fraction Test (If Needed)

If your gallbladder is visualized and your doctor wants to assess how well it contracts:

  1. You’ll be given either:
    • A fatty meal to eat, or
    • A medication called cholecystokinin (CCK) through your IV
  2. Either of these will stimulate your gallbladder to contract
  3. Additional images will be taken every 30 minutes for 90 minutes
  4. These images measure how much bile your gallbladder releases (ejection fraction)
  5. A normal ejection fraction is typically above 35% within 60 minutes

After Your Scan

  • You can resume your normal diet and activities
  • Drink plenty of fluids to help flush the tracer from your body
  • The small amount of radiation from the tracer will naturally leave your body within 24 hours
  • A nuclear medicine specialist will analyze your images and send a report to your doctor
  • Your doctor will discuss the results with you at your next appointment

What Do the Results Mean?

  • Normal scan: The tracer moves smoothly from your liver through the bile ducts to your gallbladder and then to your small intestine
  • Abnormal scan: May show:
    • Non-visualization of the gallbladder (suggesting acute cholecystitis)
    • Delayed visualization (suggesting chronic cholecystitis)
    • Low ejection fraction (indicating poor gallbladder function)
    • Blockage in the bile ducts
    • Bile leaks

Are There Any Risks?

The hepatobiliary scan uses a very small amount of radiation. The benefits of identifying gallbladder and bile duct problems far outweigh any potential risks from this minimal radiation exposure.

If morphine is used, there is a small risk of side effects such as nausea, itching, or drowsiness, but these are typically mild and short-lived.

How Long Will the Entire Procedure Take?

The entire procedure may take between 1 and 4 hours, depending on:

  • How quickly your gallbladder is visualized
  • Whether additional tests like the ejection fraction are performed
  • In some cases, you may be asked to return for additional images 24 hours later

If you have any questions or concerns about your hepatobiliary scan, please discuss them with your healthcare provider.

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