A HIDA (hepatobiliary iminodiacetic acid) scan is a diagnostic imaging procedure used to evaluate the function of the liver, gallbladder, and bile ducts.
What a HIDA Scan Is
A HIDA scan is a specialized imaging test that assesses the health and function of your biliary system. It helps diagnose issues such as inflammation of the gallbladder (cholecystitis), blockages in the bile ducts, or problems with bile flow. The procedure involves injecting a small amount of a radioactive tracer, a substance that emits gamma rays, into the bloodstream. This tracer then travels through the organs of the biliary system, allowing a special camera to capture images of its movement.
Total Time for a HIDA Scan
The actual imaging portion of a HIDA scan typically takes about 60 to 90 minutes. However, the total time you should anticipate spending at the medical facility is usually 2 to 4 hours. This extended duration accounts for preparation, the injection of the tracer, initial imaging, and potential additional phases.
The overall time can vary depending on how quickly the radioactive tracer moves through your system and whether additional imaging phases are necessary. If the gallbladder does not visualize within the initial imaging period, delayed images may be taken several hours later, or even up to 24 hours after the initial injection. Another factor is the administration of cholecystokinin (CCK), a hormone that stimulates gallbladder contraction. If CCK is given to assess the gallbladder’s ejection fraction, this adds to the imaging time, as images are taken before and after its administration.
Preparing for Your HIDA Scan
Proper preparation is important for accurate HIDA scan results. You will typically fast for 4 to 12 hours before the scan, consuming no food or drink except clear liquids. Fasting ensures the gallbladder is relaxed and full of bile, allowing for better visualization of its function.
You may also need to avoid certain medications, especially opioid pain relievers, for 6 to 24 hours prior to the test, as these can affect bile flow and interfere with accuracy. It is important to discuss all medications and supplements with your doctor before the scan. Inform your healthcare provider if you are pregnant or breastfeeding.
The HIDA Scan Procedure
Upon arrival, you will typically change into a hospital gown and lie on an examination table. A healthcare professional will insert an intravenous (IV) line, usually in your arm or hand, for the radioactive tracer injection. A gamma camera will be positioned over your abdomen to capture images as the tracer moves through your liver, bile ducts, gallbladder, and small intestine.
During imaging, remain as still as possible for clear pictures. The camera may take continuous images or a series at timed intervals. If the gallbladder doesn’t appear initially or needs further assessment, cholecystokinin (CCK) may be administered via IV to stimulate contraction. This measures the gallbladder’s ejection fraction, indicating how well it releases bile. After the scan, the IV will be removed, and you can resume normal activities.