Asian Pacifc Journal of Cancer Prevention, Vol 16, 2015 3407 DOI:http://dx.doi.org/10.7314/APJCP.2015.16.8.3407 Differentiation of Benign from Malignant Adnexal Masses by Functional 3 Tesla MRI Techniques Asian Pac J Cancer Prev, 16 (8), 3407-3412 Introduction Adnexal masses are among the most frequent gynecological surgical indications, but only a small number are malignant (Mohaghegh and Rockall, 2012; Kunpalin et al., 2014). Preoperative characterization of adnexal masses and determining the likelihood of malignancy are important in choosing the optimal management strategy (Arikan et al., 2014; Karadag et al., 2014; Tantipalakorn et al., 2014). Ultrasound (preferably transvaginal ultrasound), is the frst line imaging modality for evaluating patients with adnexal masses. Based on the patient’s menopausal state, serum cancer antigen (CA) -125 level, and US features of malignancy, risk of malignancy index (RMI) is calculated (Jacobs et al., 1990; Arun-Muthuvel and Jaya, 2014; Ozbay et al., 2015). RMI in the range of 25-200 is considered as indeterminate adnexal mass and requires further assessment with 1 Department of Radiology, Medical Imaging Center, Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Imam Khomeini Hospital, 2 Department of Gynecology Oncology, Vali-e-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran *For correspondence: Pourashraf_m@yahoo.com Abstract Background: The aim of this study was to evaluate and compare the accuracy of diffusion-weighted imaging (DWI), apparent diffusion coeffcient (ADC) value, and time-intensity curve (TIC) type analysis derived from dynamic 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 and DCE-MRI examinations, prior to surgery. DWI signal intensity, mean ADC value, and TIC type were determined for all the masses. Results: High signal intensity on DWI and type 3 TIC were helpful in differentiating benign from malignant adnexal masses (p<0.001). The mean ADC value was signifcantly lower in malignant adnexal masses (p<0.001). An ADC value<1.20×10 -3 mm 2 /s may be the optimal cutoff for differentiating between benign and 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 under the curve (AUC) of TIC was signifcantly larger than the AUCs of DWI and ADC (p<0.001 for comparison of TIC and DWI, p<0.02 for comparison of TIC and ADC value). Conclusions: DWI, ADC value and TIC type derived from DCE-MRI are all sensitive and relatively specifc methods for differentiating benign from malignant adnexal masses. By comparing these functional MR techniques, TIC was found to be more accurate than DWI and ADC. Keywords: Adnexal mass - diffusion-weighted imaging - apparent diffusion coeffcient - dynamic contrast-enhanced MRI RESEARCH ARTICLE 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 Mahrooz Malek 1 , Maryam Pourashraf 1 *, Azam Sadat Mousavi 2 , Maryam Rahmani 1 , Nasrin Ahmadinejad 1 , Azam Alipour 1 , Firoozeh Sadat Hashemi 2 , Madjid Shakiba 1 magnetic resonance imaging (MRI). MRI without and with intravenous contrast is indicated for any sonographically indeterminate adnexal mass, either with uncertain origin or intermediate RMI (Mohaghegh and Rockall, 2012; Winarto et al., 2014). In the previous years, researchers hypothesized that adding new MR techniques to a conventional MR protocol could improve the accuracy in the characterization of adnexal masses. Thus prior studies have been carried out to investigate the role of more recent functional MR techniques such as dynamic contrast-enhanced MR imaging (DCE-MRI), diffusion-weighted imaging (DWI) and its quantitative derivative, apparent diffusion coeffcient (ADC) in distinguishing benign from malignant adnexal masses, and to determine the value of adding these sequences to a conventional MR protocol (Katayama et al., 2002; Thomassin-Naggara et al., 2008a; Takeuchi et al., 2010; Li et al., 2012).