A hepatobiliary iminodiacetic acid (HIDA) scan is a diagnostic tool frequently used to evaluate gallbladder issues. Understanding this test and its effects can alleviate concerns regarding its role in assessing gallbladder health.
Understanding the HIDA Scan
A HIDA scan, also known as cholescintigraphy, is an imaging procedure that assesses the function of the liver, gallbladder, bile ducts, and small intestine. Its primary purpose is to visualize the flow of bile from the liver to the small intestine and to evaluate how well the gallbladder empties.
The procedure involves injecting a small amount of a radioactive tracer, or radiopharmaceutical, into a vein. This tracer travels through the bloodstream to the liver, where it is absorbed by bile-producing cells and then excreted into the bile. A special camera, called a gamma camera, tracks the tracer’s movement through the biliary system, capturing images that show its path into the gallbladder and then into the small intestine. This test provides functional information about these organs.
Does the HIDA Scan Worsen Gallbladder Condition?
A HIDA scan does not typically worsen an existing gallbladder condition or cause new damage to the gallbladder. The scan is a diagnostic tool designed solely to observe the function of the biliary system, rather than to interfere with or manipulate the organ in a harmful way. The radiotracer used in the procedure is biologically inert and does not cause physical harm or chemical degradation to the gallbladder tissue.
If a patient experiences symptoms after a HIDA scan, these are generally attributed to the underlying gallbladder issue being identified or stimulated during the test. For instance, a medication like cholecystokinin (CCK) may be administered during the scan to stimulate the gallbladder to contract and empty, which can temporarily recreate symptoms a patient might already experience due to their condition. This recreation of symptoms aids diagnosis and does not imply that the scan itself is causing new damage or exacerbating the condition. The scan provides information about the gallbladder’s current state; it does not negatively alter it.
Potential Side Effects of a HIDA Scan
HIDA scans are generally considered safe, with few associated risks. Most side effects are minor. Patients may experience discomfort or bruising at the site where the radiotracer is injected.
While rare, a mild allergic reaction to the radiotracer or other medications used during the scan is a possibility. If CCK is administered to stimulate gallbladder contraction, some individuals might temporarily experience mild nausea or abdominal cramping. The procedure involves a very low amount of radiation exposure, and the benefits of obtaining a diagnosis typically outweigh this minimal risk.
What HIDA Scan Results Indicate
A HIDA scan provides valuable information regarding the function of the gallbladder and bile ducts. A primary focus of the scan is to measure the gallbladder ejection fraction, which indicates how effectively the gallbladder empties bile.
Normal results show the radiotracer moving freely from the liver into the gallbladder and then into the small intestine. An abnormally low ejection fraction, often considered below 30% to 38%, can suggest gallbladder dysfunction, such as chronic cholecystitis (gallbladder inflammation). Other findings, such as slow movement of the tracer or its absence in the gallbladder, can point to issues like blockages or acute inflammation. These results help healthcare providers make informed decisions regarding diagnosis and potential treatment options.