HIDA scan test or cholescintigraphy is one of the tests used to diagnose gallbladder problems or obstructions in the bile duct. The HIDA scan exam may be advised for a patient when gallbladder disease is suspected but cannot be detected by the usual ultrasound procedure. Basically, the HIDA scan test is a scan that uses a radioactive dye, namely, hydroxy imino diaetic acid (HIDA), to trace the path of the bile produced by the liver. It can also detect the presence of tumors or gallstones in the bile duct. Introduced into the body intravenously by injection, the chemical is isolated from the blood by the liver and passes into the bile secreted by the liver. This radioactive chemical moving with the bile is tracked by a camera that can sense its presence in various organs. HIDA scan test results may also be used to determine the rate at which the gallbladder releases the bile. The HIDA scan ejection rate, also called "ejection fraction" or EF, indicates the level at which the gall bladder functions.
Pain in the upper right side of the abdomen is usually caused by gall bladder disease or obstruction of bile by gall stones. Once the radioactive dye is injected, the camera in the HIDA scan machine follows its path. If it does not appear in the liver, the probable cause is a diseased liver. If it is detected in the liver but fails to appear in the bile duct, it could indicate a blockage in the duct. Failure to appear in the gall bladder could mean that the cystic duct leading to and from the gall bladder is blocked. Detecting the presence of the chemical outside the liver, bile duct, gall bladder, intestine could mean that bile is leaking from the gall bladder or the bile duct. Sometimes a hormone cholecystokinin is injected intravenously during a HIDA scan as it makes the gall bladder contract and makes it empty all the bile it contains into the intestine. When the gall bladder is diseased, reduced contraction is observed.
In addition, an ERCP test (or endoscopic retrograde cholangiopancreatography) is also often used to detect obstructions in the biliary tract. In this procedure, a gastrocope is inserted through the mouth down into the duodenum. The radioactive dye is then injected into the gall bladder and bile duct, and then X-ray images are taken to get an idea of the extent and nature of the obstruction.More articles from the Liver Tests Category