1. Department of Radiology, Ajou University School of Medicine, Suwon 16499, Korea.
2. Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul 05030, Korea.
3. Department of Radiology, Human Medical Imaging and Intervention Center, Seoul 06524, Korea.
4. Department of Radiology, Ansan Hospital, Korea University School of Medicine, Ansan 15355, Korea.
5. Department of Radiology, New Korea Hospital, Gimpo 10086, Korea.
6. Department of Radiology, Chung-Ang University Hospital, Seoul 06973, Korea.