Differentiation of noncalculous periampullary obstruction: comparison of CT with negative-contrast CT cholangiopancreatography versus MRI with MR cholangiopancreatography

Objectives The purpose of this study was to compare CT with negative-contrast CT cholangiopancreatography (nCTCP) using subvolume minimum intensity projection (MinIP) versus MRI with MRCP in differentiating noncalculous periampullary obstruction. Methods Sixty-four patients with clinically proven noncalculous periampullary obstructions who had undergone both MDCT and MR examinations before operation were reviewed retrospectively. Two reviewers independently interpreted the two image sets (the CT with nCTCP set [CT set] vs. the MRI with MRCP set [MRI set]) in differentiating both benign from malignant obstruction and pancreatic head carcinoma (PHC) from non-PHC, and the results were compared to the final clinical records. Results In this study, no statistically significant differences were observed in the accuracy of differentiating benign from malignant periampullary obstruction ( p = 0.754 for reviewer 1 and p = 0.508 for reviewer 2) on the two image sets. The accuracy of differentiating PHC from non-PHC was also statistically insignificant ( p = 0.125 for reviewer 1 and p = 1.000 for reviewer 2) on the two image sets. Conclusion The CT set provides a comparable performance to that of the MRI set in differentiating noncalculous periampullary obstruction. Key Points • nCTCP with subvolume MinIP is a practical tool in evaluating biliary obstruction • Two image sets have a comparable performance in differentiating noncalculous periampullary obstruction • MDCT could serve as an alternative in patients not eligible for MRI