1. Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, South Korea.
2. Department of Radiology, Konyang University College of Medicine, Konyang University Hospital, Daejeon, South Korea.
3. Department of Gastroenterology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea.
4. Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea.