Medical Health Encyclopedia

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.

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.

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Endoscopic Retrograde Cholangiopancreatography (ERCP). Endoscopic retrograde cholangiopancreatography (ERCP) has been the gold standard for detecting common bile duct stones, particularly because they can be removed during the procedure. However, it is invasive and carries a risk for complications. With the advent of noninvasive imaging techniques, it is now generally limited to patients who have a high likelihood of common bile ducts stones and so would need them removed.

Computed Tomography. Computed tomographic (CT) scans may be a valuable additional imaging technique if the doctor suspects complicating features, such as perforation, common duct stones, or other problems such as cancer in the pancreas or gallbladder. Helical, or spiral, computed tomography (CT) scanning is advanced technique that shortens the time and obtains clearer images. With this process, the patient lies on a table that moves while a donut-like, low-radiation x-ray tube rotates around him or her.