1. Regional Cerebrovascular Center, Hospital and School of Medicine, chungnam National University, Daejeon, Korea.
2. Department of Neurology, Hospital and School of Medicine, Daejeon, Korea.
3. Department of Neurosurgery, Hospital and School of Medicine, Daejeon, Korea.
4. Department of Information and Statistics, College of Natural Science, Chungnam National University, Daejeon, Korea.