1. Department of Neurology, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea.
2. Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
3. Department of Neurosurgery, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Korea.
4. Department of Neurosurgery, Kwangju Christian Hospital, Gwangju, Korea.
5. Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
6. Institute of Biomedical Science, Catholic Kwandong University International St. Mary's Hospital, Incheon, Korea.
7. Department of Neurosurgery, Veterans Health Service Medical Center, Seoul, Korea.