RMG patients will be recruited in this study . This project will be designed multi-center, prospective, observational clinical research. The changes of APT signal intensity before and after treatment will be compared with those of different types of RMG line. The relationship between APT imaging characteristics and clinical end point events will be investigated and compared with conventional MR imaging technique. The sensitivity, specificity and accuracy of the progression-free survival and median overall survival will be measured after treatment with bevacizumab.