1 Department of Radiology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, PR China.
2 Department of Ultrasound, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, PR China.
3 Department of Geriatrics, Hospital of Chengdu University of Traditional Chinese Medicine, No.39 Shi-er-qiao Road, Chengdu, Sichuan 610072, PR China. Electronic address: wwb1201@vip.sina.com.