Differentiation of Benign from Malignant Adnexal Masses by Dynamic Contrast-Enhanced MRI (DCE-MRI): Quantitative and Semi-quantitative analysis at 3-Tesla MRI

Abstract

Background: To evaluate the utility of the pharmacokinetic modeling derived from dynamic contrast-enhanced<br />magnetic resonance imaging (DCE-MRI) in differentiating benign from malignant adnexal masses. Methods: A total of<br />43 patients with 49 complex adnexal masses (27 benign, 3 borderline, and 19 malignant lesions) underwent preoperative<br />DCE-MRI examinations on a 3 Tesla MRI. Using extended Tofts' model, quantitative analysis was performed in the<br />solid components of all tumors. Three pharmacokinetic parameters were defined as volume transfer coefficient (Ktrans),<br />the rate constant (Kep), and the plasma volume (Vp). Semi-quantitative analysis was also performed and the values<br />of relative signal intensity (SI rel) wash-in-rate (WIR), the initial area under the curve (iAUC60), time-to-peak (TTP)<br />and wash-out-rate (WOR) were calculated. Receiver operating characteristic (ROC) curve analysis was performed to<br />evaluate diagnostic characteristics of each DCE-MRI parameter in differentiating borderline/malignant tumors from<br />benign lesions and to provide the optimal cutoff values for these variables. Results: SI rel had the highest diagnostic value<br />(AUC=0.872; p<0.001; cut-off=121.4 associated with an overall accuracy=79.6%, sensitivity=95.5%, specificity=66.7%,<br />NPV=94.8% and PPV=70.0%). Ktrans had the second highest AUC=0.836 (p<0.001; cut-off=0.034 associated with an<br />overall accuracy=79.6%, sensitivity=86.4%, specificity=74.1%, NPV=87.0% and PPV=73.1%). The other factors found<br />to be acceptable diagnostic parameters for borderline/malignant lesions included WIR (AUC=0.816; p<0.001), iAUC60<br />(AUC=0.808; p<0.001), Vp (AUC=0.795; p<0.001), SI max (AUC=0.737, p=0.005), SI peak (AUC=0.737; p=0.005)<br />and Kep (AUC=0.681; p=0.031). Conclusion: Quantitative DCE-MRI is a relevant tool for differentiating benign from<br />malignant adnexal masses. Among all the DCE parameters, SI rel and Ktrans are the most accurate discriminators.