1. Department of Orthopedics, Memorial Hospital of Sun Yat-Sen University, Institute of Spinal Cord Injury, Sun Yat-Sen University, Guangzhou, Guangdong Province, 510120, P.R. China
2. Department of Ultrasound, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, Guangdong Province, 510060, P.R. China