Malignant Potential Assessment of Intraductal Papillary Mucinous Neoplasms of the Pancreas: Comparison between Multidetector CT and MR Imaging with MR Cholangiopancreatography

Abstract

Introduction: To compare the diagnostic performances of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) with MR cholangiopancreatography (MRCP) in predicting the malignant potential of pancreatic intraductal papillary neoplasms (IPMN) and to evaluate their inter-modality agreement.

Material and Methods: Institutional review board approval was obtained and the requirement for informed consent was waived for this retrospective study. In 129 patients with pathologically-proven pancreas IPMNs, three reviewers independently evaluated their preoperative MDCT and MRI with MRCP findings. Inter-modality agreement between MDCT and MRI with MRCP as well as interobserver agreement of each imaging modality in detecting high-risk stigmata and worrisome features were assessed. Diagnostic values of other signs of overt malignancy including the presence of parenchymal mass and locoregional extension were analyzed. Diagnostic performances and inter-modality consistency were assessed using receiver operating curve (ROC) analysis and weighted κ statistics.

Results: Overall predictability of MDCT and MRI with MRCP for the malignancy potential of pancreatic IPMNs was similar (AUC: 0.82 and 0.82, respectively) with good inter-modality agreement (κ=0.75) and moderate interobserver agreement (κ=0.47~0.59) when we set high-grade dysplasia as the cutoff for malignancy. When parenchymal masses and locoregional extensions were considered as overt malignant signs, invasive IPMN predictability was significantly increased (AUC: 0.87 for CT and 0.88 for MRI) with high sensitivity (94.3%) and equivocal specificity (69.1%).

Conclusion: Diagnostic performances in predicting the malignant potential of pancreatic IPMNs using MDCT and MRI with MRCP were similar while showing good inter-modality agreement, suggesting that interchangeable follow-up may be possible