1 Department of Neurosurgery, Veterans Health Service Medical Center, Seoul, Korea.
2 Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea. Electronic address: aronnn@naver.com.
3 Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
4 Department of Neurosurgery, Inha University Hospital, Incheon, Korea.
5 Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.