1. Division of Gastroenterology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
2. Division of Gastroenterology, Department of Hepatobiliary and Pancreatic Surgery, Yonsei University College of Medicine, Seoul, Korea
3. Division of Gastroenterology, Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea