1. Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Korea.
2. Department of Neurosurgery, Asan Medical Center, University of Ulsan College of Medicine, Korea.
3. Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Korea.
4. Department of Radiology, Samsung Medical Center, Sungkyunkwan University College of Medicine, Korea.