1. Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
2. NOTES Study Group in Korean Society of Gastrointestinal Endoscopy, Seoul, Korea.
3. Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea.