Determining Malignant Potential of Intraductal Papillary Mutinous Neoplasm of the Pancreas: CT versus MRI by Using Revised 2017 International Consensus Guidelines

Abstract

Background: Several changes have been made to the revised 2017 international consensus guidelines for management of pancreatic intraductal papillary mucinous neoplasms (IPMNs). However, the diagnostic performance is yet to he verified. Purpose: To evaluate the revised guidelines fur predicting malignant potential of pancreatic IPMNs and to compare diagnostic performance and intermodality agreement between contrast material-enhanced CT and MRI. Materials and Methods : In this retrospective study, two radiologists analyzed the preoperative contrast-enhanced CT and MRI of patients with surgically resected pancreatic IPMNs from January 2007 to December 2017. The diagnostic performance of CT and MRI were analyzed by using receiver operating curve analysis. Intermodality agreement was assessed by using weighted kappa and intra-class correlation coefficient values. Results: A total of 86 patients (mean age, 67.6 years +/- 8.9 [standard deviation]; 47 men and 39 women) with pancreatic IPMNs (benign, 58; malignant, 28) were included. At both CT and MRI, enhancing mural nodule (P < .001), abrupt main pancreatic duct caliber change (P < .001), lymphadenopathy (P = .006), larger main pancreatic duct size (P = .003), and faster cyst growth rate (P = .04) were more common in malignant than benign IPMNs. Irrespective of the modality, enhancing mural nodule of 5 mm or greater had the highest odds ratio (25 at CT vs 29 at MRI). The diagnostic performance of CT (area under the receiver operating characteristic curve, 0.83 [95% confidence interval: 0.75, 0.92]) and MRI (area under the receiver operating characteristic curve, 0.86 [95% confidence interval: 0.77, 0.95]) for predicting malignant IPMNs were comparable (P = .43), with good intermodality agreement kappa = 0.70). Conclusion: Among revised features, enhancing mural nodule of 5 mm or greater had the strongest association with malignant intraductal papillary mucinous neoplasm (IPMN), and diagnostic performance for prediction of malignant IPMNs were comparable between contrast-enhanced CT and MRI with good intermodality agreement. (C) RSNA, 2019