1. Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P. R. China
2. Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P. R. China
3. Department of Ultrasonography, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P. R. China
4. School of Stomatology, Hunan University of Chinese Medicine, Changsha, Hunan 410208, P. R. China
5. Changsha Stomatological Hospital, Changsha, Hunan 410004, P. R. China
6. Department of Pathology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital of Central South University, Changsha, Hunan 410008, P. R. China