[Dynamic Contrast-enhanced Magnetic Resonance Imaging Permeability Parameters Monitor the Early Response to Bevacizumab Plus Chemotherapy in Colorectal Cancer Patients with Liver Metastases].

Objective To investigate the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) permeability parameters in monitoring the early response to bevacizumab plus chemotherapy in colorectal cancer patients with liver metastases. Methods Magnetic resonance examinations including plain and DCE-MRI were performed in 28 colorectal cancer patients with liver metastases. The permeability parameters including the volume transfer constant (K ^trans ),extravascular extracellular volume fraction (V _e ),reverse volume transfer constant (K _ep ),and percentage of plasma volume (V _p ) were measured before chemotherapy and at the first chemotherapy cycle. All the target lesions were grouped into the hypersensitivity and hyposensitivity groups,and t test was used to calculate the statistical significance between these two groups. The receiver operating characteristic (ROC) curve analysis was also performed for evaluating the diagnostic efficacy in monitoring the early response to chemotherapy. Results Totally 64 target lesions,including 29 lesions in the hypersensitivity group and 35 lesions in the hyposensitivity group,were confirmed. The K ^trans ₀ and K _ep0 values of the hypersensitivity group were significantly higher than those of the hyposensitivity group before chemotherapy (P=0.040,P=0.049),whereas the V _e0 and V _p0 values showed no significant change between these two groups (P>0.05). When the K ^trans ₀ value was 1.129 min ^-1 ,the area under curve was 0.726,the sensitivity was 65.5%,and the specificity was 71.4%. Conclusion The DCE-MRI permeability parameters is useful for monitoring the early response to chemotherapy,and the K ^trans value can be a quantitative indicator to predict early response.