Diffusion-weighted imaging of solid or predominantly solid gynaecological adnexial masses: is it useful in the differential diagnosis?

Objectives: This study investigated whether diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values provide specific information that allows the diagnosis of solid or predominantly solid gynaecological adnexial lesions, especially whether they can discriminate benign and malignant lesions. Methods: DWI was performed in 37 patients with histologically proven solid or predominantly solid adnexial lesions (22 malignant and 15 benign neoplasms). The lesions in our data set were divided into two groups, all adnexial lesions or lesions of ovarian origin, for evaluation. The areas of the highest signal intensity on DWI (b=800 s mm(-2)) and the lowest ADC values within the lesions were evaluated. Results: On DWI, high signal intensity was observed more often in malignant than in benign lesions (p<0.0001). There was no significant difference between the ADC values of the malignant and benign lesions in either the adnexial (0.88 +/- 0.16 vs 0.84 +/- 0.42; p=0.96) or the ovarian (0.85 +/- 0.14 vs 1.05 +/- 0.2; p=0.133) lesions. When signal intensities on DWI were compared, however, malignant lesions had higher values than the benign lesions in both the adnexial (0.69 +/- 0.21 vs 0.29 +/- 0.13; p<0.0001) and the ovarian lesions (0.75 +/- 0.14 vs 0.37 +/- 0.24; p=0.003). Conclusion: On DWI, high signal intensity was observed more frequently with the malignant lesions.