1. Department of Neurological Surgery, Chung-Ang University College of Medicine, Seoul, Korea.
2. Department of Neurological Surgery, The Armed Forced Capital Hospital, Seoul, Korea.
3. Department of Radiology, The Armed Forced Capital Hospital, Seoul, Korea.
4. Division of Epidemiology and Health Index, Center for Genome Science, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Seoul, Korea.