Abdominal pain can be tough to diagnose because so many different health problems can cause it. If you have abdominal pain and your doctor suspects there’s something wrong with your gallbladder or bile ducts, they might recommend a hepatobiliary iminodiacetic acid (HIDA) scan.
What is a HIDA scan?
A HIDA scan is an imaging test that can uncover problems with the biliary system, which includes the gallbladder and the liver’s bile ducts. “It’s a simple, safe procedure that uses a small amount of radioactive material,” said Gamal Sidarous, MD, a nuclear medicine specialist with Banner - University Medicine. It’s sometimes called cholescintigraphy or hepatobiliary scintigraphy.
Why you might need a HIDA scan
A HIDA scan can help diagnose acute cholecystitis, which is gallbladder inflammation that comes on suddenly. It can also be used to:
- Diagnose chronic cholecystitis or longer-term gallbladder inflammation
- Evaluate liver function
- Look for obstructions in the bile ducts
- Check for leaks in the biliary system after surgery
- Assess a liver transplant
- Help measure how effectively your gallbladder releases bile (gallbladder ejection fraction)
Here’s when you might need a HIDA scan
Your doctor can evaluate your symptoms and help you decide if you need a HIDA scan, since you may have signs that could point to a lot of different conditions.
If you have acute cholecystitis, you may notice pain in the right upper quadrant of your abdomen, since that’s where your liver is. You could also have nausea, vomiting and pain in your back between your shoulder blades.
Your doctor may refer you for a HIDA scan if you have gallstones or gallbladder abnormalities that show up on an ultrasound or CT scan such as a thickening of the gallbladder wall, a distended gallbladder, sludge in the gallbladder or a gallbladder that does not empty properly.
Here’s what to expect during a HIDA scan
To prepare for a HIDA scan, you need to fast for four hours and stop taking morphine or morphine-related medications, since they can affect the gallbladder and the biliary system.
For the test, you’ll lay on a table and a radioactive tracer is injected in one be injected in one arm. It might feel cold. The tracer travels in your blood to your liver, and your liver cells pass it on to your biliary system. Radiologists can track the tracer with a nuclear medicine scanner, or gamma camera, and see the images on a computer. The procedure takes about an hour and doesn’t cause any discomfort, though you may feel pain from your gallbladder symptoms.
Here’s what the test might show
The radiologist can make a diagnosis depending on how the tracer moves through your body.
Sometimes, the radiologist can’t see the gallbladder. “If the duct that leads to the gallbladder is obstructed by inflammation, the radioactive material will not be able to find its way to the gallbladder, so we won’t be able to see it,” Dr. Sidarous said. “Then the material will be excreted into the bowel, and we can see it there.”
If that happens, the radiologist will suspect acute cholecystitis. To confirm the diagnosis, they can give you morphine through an IV. “Morphine obstructs the common bile ducts, which drain the radioactive material from the liver,” Dr. Sidarous said. That creates pressure in the bile ducts that reverses the flow of radioactive material and tries to force it into the gallbladder.
If the radiologist can see the gallbladder after administering morphine, it means you have chronic cholecystitis rather than acute cholecystitis. “That means you don’t need to be rushed to the operating room,” Dr. Sidarous said. “But it also signifies that your gallbladder is not functioning well.”
If the radioactive material shows up in the bowel and gallbladder, that means your liver function is probably OK.
If the radioactive material appears within the abdominal cavity in someone who recently had their gallbladder removed, that’s a sign of a bile leak that needs intervention to prevent acute peritonitis, which is swelling of the lining of your abdomen. Peritonitis is serious and can lead to organ failure and even death.
Are there any risks?
The risks and side effects of a HIDA scan are minor. You may have bruising at the site where you got the injection.
The amount of radiation exposure is very small. “People sometimes are scared because of the word ‘radioactive.’ But we do tons of tests this way on every system in the body every day. The dose of radiation delivered to the body from the radioactive source is insignificant,” Dr. Sidarous said. You’ll excrete the tracer in your urine and stool a day or two after the test.
The bottom line
If you have abdominal pain or other symptoms that point to a problem with your gallbladder or bile ducts, your doctor might recommend a HIDA scan. This test can help pinpoint the problem so you can start treatment. If you have concerns about your gallbladder or abdominal pain, connect with a health care professional at Banner Health.