1. Department of Radiology, Guangzhou Twelfth People’s Hospital, Guangzhou, China
2. Department of Radiology, Nan fang Hospital, Southern Medical University, Guangzhou, China
3. Department of Radiology, San shui District Institute for Disease Control and Prevention, Foshan Guangdong, China
4. Department of Radiology, The Third People’s Hospital of Yunnan Province, Yunnan, China.