1. Department of Radiology and Research Institute of Radiology, Asian Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2. Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
3. Department of Radiology, Seoul National University Hospital, Seoul, Korea.
4. Department of Radiology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
5. Department of Radiology, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
6. Department of Radiology, Thyroid Center, Daerim Saint Mary's Hospital, Seoul, Korea.