MR cholangiopancreatography and MR urography: improved enhancement with a negative oral contrast agent.

At magnetic resonance (MR) cholangiopancreatography and MR urography with an oral negative contrast agent, low signal intensity was produced in phantoms. In 20 patients suspected of having biliary tract and pancreatic diseases and in 20 healthy volunteers, the signal intensity in the gastrointestinal tract was almost completely eliminated with the negative contrast agent. Differences in image quality between pre- and postcontrast images were statistically significant.