The utility of diffusion-weighted MR imaging in cervical cancer

Purpose: To investigate the value of diffusion-weighted MR imaging (DWI) in detection of cervical cancer, and to determine the diagnostic accuracy of apparent diffusion coefficient (ADC) values for evaluating cervical cancer before and after chemoradiotherapy. Materials and methods: Thirty-three patients with cervical squamous carcinoma and 20 patients with other pelvic abnormalities underwent diffusion-weighted imaging (DWI) in addition to routine MR imaging. The ADC values of normal cervical tissue, cervical area before and after chemoradiotherapy were measured and compared. Receiver operating characteristic (ROC) analysis was employed to investigate whether ADC values could help in discrimination among normal cervical tissue, cervical cancer before and after therapy, and to obtain the optimal ADC threshold value. Results: Cervical cancer lesion demonstrated obviously hyperintensity on DWI images. The mean ADC value of cervical carcinoma (1.110 ± 0.175 x 10-3 mm2/s) was significantly lower than that of normal cervical tissue (1.593 ± 0.151 x 10-3 mm2/s) (P < 0.001). The mean ADC value of the cervical area in 22 patients treated by chemoradiotherapy (1.436 ± 0.129 x 10-3 mm2/s) was significantly higher than that before therapy (1.013 ± 0.094 x 10-3 mm2/s) (P < 0.001). The difference of ADC values between normal cervical tissue and cervical area after therapy was statistically significant (P < 0.01). The optimal ADC threshold values for distinguishing between normal cervical tissue and cervical carcinoma was 1.359 x 10-3 mm2/s, between cervical area before and after therapy was 1.255 x 10-3 mm2/s, between normal cervical tissue and cervical area after therapy was 1.525 x 10-3 mm2/s. The sensitivity and specificity were 100% and 84.8%, 95.5% and 100%, 70% and 81.8%, respectively. Conclusion: DWI can be applied for the detection of cervical cancer because of its superior disease contrast with normal tissue. The measurement of the ADC values can be a useful tool to monitor the response to therapy for cervical carcinoma.