Diagnostic accuracy of diffusion restriction in intraductal papillary mucinous neoplasm of the pancreas in comparison with "high-risk stigmata" of the 2012 international consensus guidelines for prediction of the malignancy and invasiveness.

Background It is debated whether diagnostic performance of diffusion-weighted imaging (DWI), which is widely used for detection and characterization of various malignant tumors, is comparable with high-risk stigmata of 2012 international consensus guidelines (ICG) for diagnosis of intraductal papillary mucinous neoplasms (IPMNs). Purpose To evaluate the diagnostic accuracy of diffusion restriction in IPMNs for prediction of malignancy and invasiveness in comparison with high-risk stigmata of 2012 ICG. Material and Methods This retrospective study was institutional review board approved and informed consent was waived. A total of 132 patients with surgically proven IPMNs (49 malignant, 83 benign) who underwent gadoxetic acid-enhanced magnetic resonance imaging (MRI), magnetic resonance cholangiopancreatography (MRCP), and DWI with a b-value of 0, 100, and 800 s/mm2 using a 3.0 T MR system were included. Two radiologists independently evaluated imaging parameters of high-risk stigmata and worrisome features of 2012 ICG and diffusion restriction in IPMNs. Univariate and multivariate logistic regression analyses and McNemar's test were used for statistical analysis. Results The presence of diffusion restriction in IPMNs was the only independent imaging parameter for prediction of malignancy (odds ratio [OR], 11.98; 95% confidence interval [CI], 3.60-39.87; P < 0.001) and invasiveness (OR, 17.92; 95% CI, 3.91-82.03; P < 0.001) on multivariate analysis. The diagnostic accuracy and specificity of diffusion restriction were significantly improved compared to high-risk stigmata of 2012 ICG to prediction of malignant ( P = 0.006 and P < 0.001, respectively) or invasive IPMNs ( P = 0.009 and P = 0.015, respectively). Conclusion The diffusion restriction in IPMNs could be considered as another high-risk stigma of malignancy and predictor for invasiveness.