Advanced ovarian cancer: multiparametric MR imaging demonstrates response- and metastasis-specific effects.

ABSTRACT

PURPOSE: To investigate the role of multiparametric magnetic resonance (MR) imaging in the evaluation of response to platinum-based neoadjuvant chemotherapy in advanced ovarian cancer and to compare imaging parameters between primary ovarian mass and metastatic disease. MATERIALS AND METHODS: Evaluable patients suspected of having advanced ovarian carcinoma were enrolled in a prospective protocol-driven study. Research ethics committee approval and written informed consent were obtained. Multiparametric MR imaging (diffusion-weighted MR imaging, dynamic contrast material-enhanced [DCE] MR imaging, and hydrogen 1 MR spectroscopy) was performed with a 3.0-T wholebody MR imaging system. Three marker lesions-primary ovarian mass, omental cake, and peritoneal deposit-were outlined by a radiologist on apparent diffusion coefficient (ADC) and vascular signal fraction (VSF) maps and on DCE MR images. Comparisons of mean ADC, mean VSF, DCE MR imaging parameters, and choline concentration between responders and nonresponders were based on Response Evaluation Criteria in Solid Tumors and CA-125 criteria. RESULTS: Twenty-two patients were evaluable. The mean ADC for peritoneal metastases was lower than that for ovarian (P = .015) and omental (P = .006) sites. There were no differences in pretreatment DCE MR imaging parameters between tumor sites. After treatment, responders showed a significantly larger increase in ADC (P = .021) and fractional volume of the extravascular extracellular space (v(e)) (P = .025) of ovarian lesions compared with nonresponders, but there was no change in ADC at other sites. Pre- and posttreatment values of choline concentration of ovarian lesions were lower in responders (P = .025) than in nonresponders (P = .010). CONCLUSION: The significant differences in baseline ADCs among primary ovarian cancer, omental cake, and peritoneal deposits indicate that diffusivity profiles may be tumor-site dependent, suggesting biologic heterogeneity of disease. ADC and v(e) parameters correlated with the cytotoxic effects of platinum-based therapy and may be useful response markers, while choline concentration predicted but did not reflect response.