1. Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
2. Cancer Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
3. Department of Radiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
4. Center for Cancer Prevention and Detection, National Cancer Center, Goyang-si, Republic of Korea