1. Department of Spine Surgery Beijing Jishuitan Hospital Beijing China
2. Beijing Research Institute of Traumatology and Orthopaedics Beijing China
3. Center for Magnetic Resonance Research, Department of Radiology, Medical School University of Minnesota Minneapolis Minnesota USA
4. Beijing Hospital, National Center of Gerontology Beijing China
5. Department of Radiology Beijing Jishuitan Hospital Beijing China
6. Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine Tsinghua University Beijing China