Medical Health Encyclopedia

X-Rays. Standard x-rays of the abdomen may detect calcified gallstones and gas. Variations include oral cholecystography or cholangiography.

In oral cholecystography the patient takes a tablet containing a dye the night before the text. The dye fills the gallbladder and x-rays are used to take images of it the next day. It has been available since 1924 but has largely been replaced by ultrasound. It is more sensitive than standard x-rays, however, and may be useful in some cases for determining the structural and functional status of the gallbladder, often before nonsurgical procedures.

Cholangiography uses a dye injected into the bile duct and x-ray to view the common bile duct. It is typically used during operations to provide a clear image of the biliary tract.

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Cholescintigraphy (Also Called Gallbladder Radionuclide Scan). Cholescintigraphy, a nuclear imaging technique, is more sensitive than ultrasound for diagnosing acute cholecystitis. It is noninvasive but can take one to two hours and even longer. The procedure involves the following steps:

• A tiny amount of a radioactive dye is injected intravenously. This material is excreted into bile.
• The patient lies on a table under a scanning camera, which detects gamma rays emitted by the dye as it passes from the liver into the gallbladder.
• The test can take up to two hours, since each image takes about a minute and they are taken every five to 15 minutes.

If the dye does not enter the gallbladder, the cystic duct is obstructed thereby indicating acute cholecystitis. The scan cannot identify individual gallstones or chronic cholecystitis. Occasionally the scan gives false positive results. (In other words, it appears to detect acute cholecystitis in people who do not have the condition.) Such results are most likely in alcoholic patients with liver disease or patients who are fasting or receiving all nutrients intravenously.