1. Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.
2. Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea.
4. Department of Radiology, Dongsan Medical Center, Keimyung University College of Medicine, Daegu, Korea.
5. Department of Radiology, Korea University Anam Hospital, Seoul, Korea.