Differentiation of Benign from Malignant Adnexal Masses by Functional 3 Tesla MRI Techniques: Diffusion-Weighted Imaging and Time-Intensity Curves of Dynamic Contrast-Enhanced MRI

Background: The aim of this study was to evaluate and compare the accuracy of diffusion-weighted imaging(DWI), apparent diffusion coefficient (ADC) value, and time-intensity curve (TIC) type analysis derived fromdynamic contrast-enhanced MR imaging (DCE-MRI) in differentiating benign from malignant adnexal masses.Materials and
Methods: 47 patients with 56 adnexal masses (27 malignant and 29 benign) underwent DWI andDCE-MRI examinations, prior to surgery. DWI signal intensity, mean ADC value, and TIC type were determinedfor all the masses.
Results: High signal intensity on DWI and type 3 TIC were helpful in differentiating benignfrom malignant adnexal masses (p<0.001). The mean ADC value was significantly lower in malignant adnexalmasses (p<0.001). An ADC value<1.20×10-3 mm2/s may be the optimal cutoff for differentiating between benignand malignant tumors. The negative predictive value for low signal intensity on DWI, and type 1 TIC were 100%.The pairwise comparison among the receiver operating characteristic (ROC) curves showed that the area underthe curve (AUC) of TIC was significantly larger than the AUCs of DWI and ADC (p<0.001 for comparison ofTIC and DWI, p<0.02 for comparison of TIC and ADC value).
Conclusions: DWI, ADC value and TIC typederived from DCE-MRI are all sensitive and relatively specific methods for differentiating benign from malignantadnexal masses. By comparing these functional MR techniques, TIC was found to be more accurate than DWIand ADC.