ABSTRACT
Objective To investigate the MRI findings of duodenal papillary adenocarcinoma(DPA),and to evaluate the importance of diffusion-weighted imaging(DWI)in diagnosis of DPA.Methods A complete data of 52 patients with DPA were prospectively collected.All patients underwent surgery within 72 hours after conventional MRI,DWI and MRCP scans.Before surgery,four different MRI findings were used to calculate the sensitivity,specificity and the probability of correctness.Two experienced radiologists who were blind to the pathologic diagnosis handled the MRI findings.Thirty eight patients were pathologically diagnosed for DPA.Based on the pathological diagnosis,the detection rate of DPA by the MR sequence was recorded and the chi square test was used to do the statistical analysis. Results The accuracy rate in diagnosis of DPA with MRI was 78.8% in our study.The findings of DPA consist of thickening wall of duodenal,duodenal papilla node imaging,DWI showing high signal of duodenal papilla and"beak"sign of dilated bile duct.Corresponding sensitivities were 70.5%,66.7%,86.3% and 87.9%,and specificities were 75.0%,30.0%,50.0% and 63.1% respectively.The incidences of positive on T2WI and T1WI,MRCP,DWI scans were 60.5%,76.3% and 92.1% respectively.The detection rate of each sequence has significant difference(χ2=10.48,P<0.005).Conclusion The MRI manifestations of DPA consist of thickening wall of duodenal,duodenal papilla node imaging,DWI showing high signal of duodenal papilla and"beak"sign of dilated bile duct.The detection rate of DWI sepuence on DPA lesions is significantly higher than that of other sequences.