1. Department of Radiology, Soonchunghyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
2. Department of Neurosurgery, Soonchunghyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
3. Department of Radiology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea.