What is the role of ultrasonography (US) in the workup of biliary obstruction?

Updated: Oct 16, 2019
  • Author: Jennifer Lynn Bonheur, MD; Chief Editor: Vinay Kumar Kapoor, MBBS, MS, FRCS, FAMS  more...
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Ultrasonography is the least expensive, safest, and most sensitive technique for visualizing the biliary system, particularly the gallbladder. Current accuracy is close to 95%.

This is the procedure of choice for the initial evaluation of cholestasis and for helping differentiate extrahepatic from intrahepatic causes of jaundice. Extrahepatic obstruction is suggested by the presence of dilated intrahepatic bile ducts, but the presence of normal bile ducts does not exclude obstruction that may be new or intermittent.

Visualization of the pancreas, kidney, and blood vessels is also possible.

Ultrasonography is considered somewhat limited in its overall ability to help detect the specific cause and level of obstruction. US is not as useful for CBD stones (bowel gas may obscure visualization of the CBD). The cystic duct is also poorly imaged. In addition, it is less useful diagnostically in individuals who are obese.

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