Pancreatic imaging gets the flavor of the tropics

Could patients with possible biliary and/or pancreatic disease soon be offered a pina colada before imaging? Not quite, but a team of Belgian radiologists has started serving pineapple juice labeled with gadolinium to boost the quality of its MR cholangiopancreatography scans.

MRCP exams typically use heavily T2-weighted sequences to visualize the biliary and pancreatic ducts. Administration of a negative oral contrast agent improves overall depiction of target anatomy and reduces distracting signal from stomach and duodenal fluids. But the contrast agents can be expensive, difficult to acquire, and downright unpalatable.

Radiologists at the Erasme Hospital, Free University of Brussels, began their quest for a cheap, tasty MRCP negative oral contrast agent after learning that the manganese content of blueberry juice invoked paramagnetic behavior. Few Belgian stores stock blueberry juice, however, and patients in previous trials had complained of its sour taste.

"We tested almost all of the juices on the market," said lead author Dr. Emmanuel Coppens. "Mango and other tropical fruit drinks showed frank hyperintensities on heavily T2-weighted sequences, almost like water. There were reports of green tea, also very rich in manganese, working as a negative oral contrast agent for MRCP. Pineapple juice had the advantages over green tea of being prepackaged, ready to use, cold, better tasting, and more reproducible in preparation."

Coppens and colleagues tested the tropical contrast in 35 consecutive patients referred for MRCP with suspected biliopancreatic disease. Their prescan cocktail consisted of 180 mL pineapple juice mixed with 1 mL Gd-DOTA. Comparison of signal values and image quality revealed significant improvement after ingestion of the drink, which patients sipped happily while lying supine (Euro Radiol 2005;15[10]:2122-2129).

"The taste of the juice is not adulterated by the addition of 1 mL Gd-DOTA," Coppens said. "The agent that we previously administered had a vague orange-flavored metallic taste and a thick consistency, making it more difficult to drink through a straw."

Patients presenting for MRCP at hospitals linked by the Free University of Brussels now routinely receive a pineapple drink before their exam. One liter of the fruit juice costs less than $2, depending on where it is purchased, and that should be sufficient for five scans, Coppens said.