1. Departments of Radiology and
2. Neurosurgery, Eulji University Hospital, Daejeon;
3. Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon; and
4. Department of Radiology, Yonsei University, Seoul, Republic of Korea
5. Neurosurgery, Sungkyunkwan University School of Medicine Kangbuk Samsung Hospital, Seoul;