This study will be designed as multi-center, prospective, observational clinical research. 100 cases of RMG patients in Zhujiang Hospital and Nanfang Hospital will be recruited. The patients will be examined with conventional MRI and APT-MRI imaging of 3.0T high field MRI. The treatment of different types of RMG line will be scanned with APT protocol. The changes of signal intensity will be studied. The relationship between APT imaging characteristics and clinical end point events will be observed and compared with conventional MR imaging technique. Two techniques will be used to predict the the 6-month progression-free survival after bevacizumab treatment. The aim of this study is to determine whether APT can predict the efficacy of bevacizumab in the treatment of RMG, and which RMG is effective and sensitive to bevacizumab therapy .Also,we will evaluate the feasibility of APT-MR imaging as a surrogate biomarker for predicting the efficacy of targeted therapy and to establish the basic criteria for the selection of individualized targeted therapy regimens for RMG.