1. Department of Radiology, Ajou University School of Medicine, Ajou University Medical Center, Suwon, Korea.
2. Department of Neurosurgery, Ajou University School of Medicine, Ajou University Medical Center, Suwon, Korea.
3. Office of Biostatistics, Medical Research Collaborating Center, Ajou Research Institute for Innovative Medicine, Ajou University Medical Center, Suwon, Korea.
4. Department of Radiology, Kangwon National University College of Medicine, Chuncheon, Korea.