Oral Gd-DTPA as a negative gastrointestinal contrast agent in magnetic resonance cholangiopancreatography

Objective : To evaluate the value of oral Gd-DTPA as a negative contrast agent during magnetic resonance cholangiopancreatography (MRCP) to eliminate the high signals of the gastrointestinal tract. Methods: To select the optimal concentration of oral Gd-DTPA for MRCP, a phantom study was performed followed by clinical trial in 15 cases undergoing MRCP before and after oral Gd-DTPA (in a total volume of 250 ml 1:5 diluted Gd-DTPA, 1.488 g/L). MRCP images were acquired using two-dimensional single slice fast spin-echo ( SSTSE) sequence and half-Fourier acquisition single slice fast spin-echo (HASTE) sequence. Results: The phantom study showed that the 1:5 diluted oral Gd-DTPA was best in decreasing the signal intensity both in T2-weighted imaging (59. 5% ) and in HASTE sequence (82.45% ). The high signal intensity of the stomach and intestinal fluid was completely suppressed in all the cases. The depictions of the common bile duct and pancreatic duct were markedly improved by using the oral contrast agent