1. Institute for Digestive Research, Digestive Disease Center, Department of Internal Medicine, Soonchunhyang University College of Medicine, Seoul, Korea.
2. KASCU (Korean Association for the Study of Contrast Enhanced Ultrasonography), Korea.
3. Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.
4. Department of Internal Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Guri, Korea.
5. Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea.
6. Department of Internal Medicine, Soonchunhyang University College of Medicine, Cheonan, Korea.
7. Department of Internal Medicine, Hallym University Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Korea.
8. Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea.
9. Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea.
10. Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon, Korea.