1. Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea
2. Department of Radiology, Seoul National University College of Medicine, Seoul, Korea
3. Department of Radiology, Konkuk University Hospital, Seoul, Korea
4. Department of Radiology, Korea University Anam Hospital, Seoul, Korea
5. Department of Radiology, Keimyung University Dongsan Medical Center, Daegu, Korea
6. Department of Radiology and Neurosurgery, Seoul National University College of Medicine, Seoul, Korea