1. Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, Fujian 361004, P.R. China
2. Department of Medical Imaging and Ultrasound, Zhongshan Hospital of Xiamen University, Xiamen, Fujian 361004, P.R. China
3. Department of Critical Care Medicine, Zhongshan Hospital of Xiamen University, Xiamen, Fujian 361004, P.R. China
4. Department of Clinical Medicine, West China School of Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China