Eun Ju Ha1, Jung Hwan Baek2, Dong Gyu Na3. 1. Department of Radiology, Ajou University School of Medicine, Wonchon-Dong, Yeongtong-Gu, South Korea. 2. Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, South Korea. Electronic address: radbaek@naver.com. 3. Department of Radiology, GangNeung Asan Hospital, Gangwon-do, South Korea.