Cholangiopancreatography with magnetic resonance. Clinical use of a new "inversion-recovery" sequence

This study was aimed at correlating the yield of a three-dimensional (3D) inversion-recovery (IR) turbo spin-echo MR cholangiopancreatography (MRCP) sequence with that of ERCP and PTC in the imaging of the normal and abnormal biliopancreatic tract. Thirty patients with suspected biliary and pancreatic diseases were examined with MRCP first and then with ERCP or PTC; they were also submitted to US, CT and conventional MR studies and in 5 of them CT cholangiography was also performed. Five patients were normal and 25 had various obstructive abnormalities: 5 patients had gallbladder stones, 8 common bile duct stones, 5 a cholangiocarcinoma and 7 an adenocarcinoma of the pancreatic head or papilla. MRCP was performed with a superconductive magnet at 0.5 T, with volumetric images on coronal planes acquired using an IR turbo SE sequence (TR 2500, TE 1000, TF 89, 4 NEX) with respiratory triggering and vascular presaturation. Segmental intrahepatic bile ducts were correctly depicted in all the patients with benign or malignant obstruction of the common bile duct, but with some respiratory artifacts. Common bile duct stones were correctly depicted in 7 of 8 patients, but studying also the single coronal slices. With this method, the stones were clearly demonstrated in 22 examined gallbladders. Neoplastic obstruction and the obstruction level were correctly identified in all patients. Pancreatic ducts were shown in normal patients and in 8 of 13 patients with neoplastic or lithiasic obstruction of the common bile duct mainly on the pancreatic head. ERCP was carried out successfully in 5 patients with common bile duct stones and in 7 patients with neoplastic obstruction; in the other cancer patients, PTC was necessary. To conclude, respiratory-triggered 3D IR turbo spin-echo MRCP is a noninvasive technique to study mostly biliary conditions which yields similar information to ERCP and PTC in a large number of patients. Moreover, this sequence can be used with midfield MR units to study the obstruction of the biliary and pancreatic ducts not only when invasive techniques fail, but also routinely.