Department of Gastroenterology and Hepatology, The Affiliated Hospital of Academy of Military Medical Sciences, Beijing 100071, China;
Endoscopy Center, 307th Hospital of The Chinese People's Liberation Army, Beijing 100071, China;
Department of Gastroenterology and Hepatology, The Affiliated Hospital of Academy of Military Medical Sciences, Beijing 100071, China;
Department of Gastroenterology and Hepatology, The Affiliated Hospital of Academy of Military Medical Sciences, Beijing 100071, China;