1. Department of Neurosurgery, Hallym University Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
2. Department of Radiology, Kwandong University Myongji Hospital, Kwandong University College of Medicine, Goyang, Korea.
3. Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
4. Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.