Bile duct stones: diagnosis with MR cholangiography and helical CT.

MR cholangiography (MRC) is a highly accurate, noninvasive method for diagnosing bile duct stones. Various breath-hold and non-breath-hold techniques for MRC have been used successfully to depict stones in the intrahepatic and extrahepatic biliary tree. Although detection of stones with MRC is usually straightforward, attention to technical details is important to avoid false-negative and false-positive interpretations. With the advent of helical CT, other options for noninvasive imaging of the bile ducts, such as CT cholangiography, are now available. CT techniques are especially useful when MRI is unavailable or contraindicated, or when the quality of MRC images is suboptimal.