1. Department of Ultrasonography, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
2. Department of Gastroenterology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
3. Department of Nursing, The Affiliated Qingdao Hiser Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
4. Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China