Comparison of magnetic resonance and endoscopic retrograde cholangiopancreatography in malignant pancreaticobiliary obstruction

Hypothesis: We hypothesize that magnetic resonance cholangiopancreatography (MRCP) is comparable to endoscopic retrograde cholangiopancreatographic (E RCP) as a diagnostic tool in patients with malignant biliary obstruction. Design: Eighteen patients with suspected pancreaticobiliary malignancy were evaluated by ERCP and MRCP in 8 months (March 1, 1996, to October 31, 1996 ). Magnetic resonance cholangiopancreatography was performed with a 1.5-T s canner using 4-mm slices. Images were obtained in a 14- to 28-second breath -hold. Images from MRCP were retrospectively evaluated by a radiologist for image quality, ductal dilation, level of obstruction, and overall diagnost ic impression. Images from ERCP were retrospectively evaluated by a biliary endoscopist (L.H.S.) and served as the standard for calculating sensitivit y, specificity, and positive predictive values. In addition, intraoperative findings were compared with MRCP results in all patients explored. Results: Diagnostic-quality EVLR images were obtained in 18 patients (100%) . Diagnostic-quality endoscopic images were obtained in 16 89%) of 18 attem pted biliary cannulations and 11 (78%) of 14 attempted pancreatic cannulati ons. Magnetic resonance CP accurately delineated the level of extrahepatic biliary ductal obstruction in 13 (87%) of 15 patients. More important, MRCP provided valuable staging information in most patients. Findings from MRCP correlated with operative findings (size and location of tumor and mesente ric vascular involvement) in 8 (80%) of 10 patients who underwent surgery, while failing in 2 patients (20%) with carcinomatosis. Conclusions: Magnetic resonance CP is a sensitive study for detecting the p resence and level of biliary ductal obstruction in patients with cancer. Th e results are comparable to those of ERCP; however, MRCP provides additiona l data regarding extent of disease that is not available from ERCP alone.