1. Huaxi MR Research Center (HMRRC), Department of Radiology, Functional and molecular imaging Key Laboratory of Sichuan Province, National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China HospitalSichuan University Chengdu 610041 P. R. China
2. Department of Pharmacy of the Affiliated Hospital of Southwest Medical UniversitySouthwest Medical University Luzhou Sichuan Province 646000 P. R. China
3. Department of Radiology, Chongqing General HospitalUniversity of Chinese Academy of Sciences (UCAS) 104 Pipashan Zheng Street Chongqing 400014 P. R. China
4. West China School of MedicineSichuan University Chengdu 610041 P. R. China
5. Amgen Bioprocessing CentreKeck Graduate Institute Claremont CA 91711 USA