Medical Health Encyclopedia

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.

Magnetic Resonance Imaging (MRI). MRIs may be very useful for detecting common bile duct stones, particularly a specific MRI technique called magnetic resonance cholangiography (MRC). It employs magnetic resonance imaging (MRI) and cholangiography, in which a dye is injected into the bile duct and x-rays are used to view the duct. MRC is extremely sensitive in detecting biliary tract cancer. This imaging procedure is very expensive, however, and may not detect very small stones or chronic infections in the pancreas or bile duct. As with EUS, it is most likely to be useful in a small subset of patients and would not eliminate the need for ERCP in most patients.

Click the icon to see an image of a cholangiogram.

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Virtual Endoscopy. Virtual endoscopy is an investigative technique that uses data from CT and MRI scans to generate a three-dimensional internal view of various body structures. The images resemble those used in endoscopy but the procedure is noninvasive. It one study it was able to detect smaller stones in the common bile duct than MRI. At this time it is still experimental.