1. Department of Colorectal and Anal Surgery, The First Hospital of Jilin University, Changchun, Jilin 130000, P.R. China
2. Department of Ultrasound, The China-Japan Union Hospital of Jilin University, Changchun, Jilin 130000, P.R. China
3. Center for Private Medical Service and Healthcare, The First Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
4. Department of Hepatobiliary and Pancreas Surgery, The First Hospital of Jilin University, Changchun, Jilin 130000, P.R. China