Differentiation of pancreatic ductal adenocarcinoma from inflammatory mass: added value of magnetic resonance elastography

Abstract

To examine whether incorporating magnetic resonance elastography (MRE) with contrast-enhanced computed tomography (CE-CT) or dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can provide a benefit in differentiating pancreatic ductal adenocarcinoma (PDAC) from inflammatory mass (IM). Thirty patients with IM and 56 patients with PDAC confirmed by histopathology were identified retrospectively via a prospectively maintained database. All patients underwent CE-CT or DCE-MRI together with dual-frequency MRE at 40 and 60Hz. A five-point scale for likelihood of pancreatic malignancy was used by two experienced radiologists in consensus. Diagnostic accuracy of CE-CT/DCE-MRI, MRE, and their combination (modeled by logistic regression analysis) was estimated using receiver operating characteristic (ROC) analysis with a leave-one-out cross validation. Accuracies for determination of PDAC by 60-Hz MRE, 40-Hz MRE, CE-CT/DCE-MRI, and the combination of CE-CT or DCE-MRI and 60- and 40-Hz MRE, were 70.2%, 77.4%, 83.3%, 75%, and 92.9%, respectively. CE-CT or DCE-MRI combined with 40-Hz MRE significantly improved diagnostic performance versus CE-CT or DCE-MRI alone (area under the ROC curve [AUC]: 0.937 versus 0.783, p<0.01) by increasing specificity (96.9% versus 62.1%, p=0.002) without a significant loss of sensitivity (90.9% versus 94.6%, p=0.727), while combined CE-CT or DCE-MRI with 60-Hz MRE did not significantly change diagnostic performance versus CE-CT/DCE-MRI alone (AUC: 0.760 versus 0.783, p=0.697). Combined assessment by 40-Hz MRE with CE-CT/DCE-MRI may help to differentiate PDAC from IM in a relatively non-invasive fashion.