1. Department of Gastroenterology, Caoxian People’s hospital, Heze, Shandong, China
2. Department of Ultrasound, Yidu Central Hospital of Weifang, Weifang, Shandong, China
3. Department of Cardiovasology, Liyang People’s Hospital, Liyang, Jiangsu, China
4. Department of Ultrasonography, Zibo City Linzi District People’s Hospital, Zibo, Shandong, China
5. Department of General Surgery, The First Affiliated Hospital of Shandong First Medical University, Jinan, Shandong, China
6. Department of General Surgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China