1. Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
2. Division of Biomedical Engineering, Hankuk University of Foreign Studies, Yongin, Korea.
3. Department of Neurology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.
4. Department of Neurology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.