MR imaging of the biliary system.

MR imaging has a distinct role to play in two areas of hepatobiliary imaging that continue to challenge the radiologist--evaluation of the gallbladder and evaluation of the jaundiced patient. The distinction between primary gallbladder carcinoma and chronic cholecystitis remains a diagnostic dilemma for all cross-sectional imaging modalities. MR imaging may be useful in detection of local invasion or metastatic disease. Gallstones are commonly seen coincidentally on cross-sectional imaging studies; the imaging characteristics of gallstones must be well-understood for the interpretation of routine abdominal MR examinations. The evaluation of jaundice is a multimodality process, often requiring three or four separate imaging techniques to determine the cause of biliary obstruction. MR may supplant more invasive techniques for anatomic depiction prior to therapeutic intervention.