Pancreaticobiliary juice reflux in patients with a morphologically normal ductal system: Assessment using unenhanced MRI with spin labeling

OBJECTIVE. The purpose of this article is to evaluate pancreaticobiliary reflux and to assess its correlation with clinical findings in patients without morphologic pancreaticobiliary maljunction by using a new MRI technique. MATERIALS AND METHODS. A total of 320 consecutive patients with suspected pancreaticobiliary diseases underwent MRCP and flow analysis by MRI. MRI flow analysis, clinical, and laboratory findings of each patient were retrospectively reviewed. The visible pancreaticobiliary reflux was graded on a 5-point confidence scale. RESULTS. Among all 320 patients with pancreatic juice reflux, 14.1% had reflux scored as grades 4 and 5 combined, and 5.0% had reflux scored as grade 5. By univariate analysis and multivariate analysis, a relatively long common channel was found to be the only significant causal factor for pancreatic juice reflux. Of patients with pancreatic juice reflux of grade 4 or 5, 11.1% (5/45) also had biliary malignancies; 18.8% (3/16) of those with pancreatic juice reflux of grade 5 had biliary malignancies. Conversely, pancreatic juice reflux of grade 4 or 5 occurred in 35.7% (5/14) of patients with biliary malignancies, and reflux of grade 5 occurred in 21.4% (3/14) of those patients. CONCLUSION. It was possible to evaluate pancreaticobiliary reflux using an MRI technique that may be suitable as a screening tool. Our results revealed that pancreaticobiliary reflux is relatively frequent in individuals without pancreaticobiliary maljunction.