Diffusion-Weighted Magnetic Resonance Imaging of Ovarian Tumors: Differentiation of Benign and Malignant Solid Components of Ovarian Masses

Objective: We evaluated the feasibility of diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) measurement in differentiating benign and malignant ovarian tumors. Methods: Surgically proven 49 ovarian tumors (39 malignant/borderline malignant and 10 benign) were examined. Results: The solid portion of all 39 malignant tumors showed homogeneous or heterogeneous high intensity on DWI, whereas only 3 of the 10 benign tumors (3 thecomas) showed high intensity. The mean (SD) ADC value in the 39 malignant tumors (1.03 [0.19]) was significantly lower than that in 10 benign tumors (1.38 [0.30]). A relatively low ADC (1.08-1.20) in the 3 thecomas may reflect their abundant cellular nature, and the presence of low intensity on T2-weighted images was suggestive for benign fibrous tumor. Conclusions: Low intensity on DWI with high ADC may suggest benign lesions; however, it may be occasionally difficult to differentiate benign and malignant lesions only on the basis of DWI.