Hyperintense Uterine Myometrial Masses on T2-Weighted Magnetic Resonance Imaging

OBJECTIVE: The objective was to determine whether diffusion-weighted imaging (DWI) might be useful in differentiating uterine leiomyomas exhibiting hyperintensity on T2-weighted images from malignant lesions. METHODS: Thirty-four uterine myometrial lesions including 7 malignant tumors and 27 leiomyomas (6 cellular leiomyomas [CLM] and 21 degenerated leiomyomas [DLM]) were evaluated. The apparent diffusion coefficients (ADC) in cellular portions of the lesions were measured (10(-3) mm2/s). RESULTS: All malignant tumors showed high signal intensity on DWI with low ADC (mean [SD], 0.79 [0.26]), which was significantly lower (P < 0.01) than that in benign leiomyomas (1.51 [0.33]). The ADC in CLM (1.18 [0.16]) was significantly lower (P < 0.01) than that in DLM (1.60 [0.30]) and higher (P < 0.05) than that in malignant tumors. CONCLUSIONS: It was difficult to differentiate malignant tumors from leiomyomas on the basis of signal intensity on DWI; however, the ADC measurement may be helpful to distinguish malignant tumors, CLM, and DLM.