Pancreatic imaging gets a taste of the tropics

Could patients with possible biliary and/or pancreatic disease soon be offered a piña 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 has been shown to improve overall depiction of target anatomy and reduce distracting signal from stomach and duodenal fluids. But the relevant contrast agents can be expensive, difficult to acquire, and downright unpalatable.

Radiologists from the Erasme Hospital, Free University of Brussels, began their quest for a tasty, cheap MRCP negative oral contrast agent after learning how the manganese content in 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 Dr. Emmanuel Coppens, lead author of the study published in the October European Radiology. "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 with a better taste, and more reproducible in preparation."

Coppens and colleagues tested the tropical contrast on 35 consecutive patients referred for MRCP with suspected biliopancreatic disease. Their prescan cocktail used 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 quite happily while lying supine.

"The taste of the juice is not adulterated by the addition of 1 mL Gd-DOTA," Coppens said. "The agent that we used to administer 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 the grocer, and is sufficient for five scans, Coppens said.

Using a larger volume of juice could remove the need for Gd-DOTA at all. This option is unlikely to be workable for pineapple juice, though, owing to the varying concentrations of key ions between - and even within - brands.

"The question would be to find a particular fruit juice with manganese and/or iron levels that were so high that variations in these concentrations did not modify the behavior of the juice on the MRCP sequence," he said.

For more information from the Diagnostic Imaging archives:

Patients breathe easy with bile duct imaging technique

Studies validating MRCP catch up with clinical reality

Imaging helps reveal tumors of the bile duct

MR complements CT in splenic diagnoses