1. Department of Diagnostic Radiology, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.
3. Division of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Korea.
4. Division of Medicine, Yonsei University College of Medicine, Seoul, Korea.
5. Department of Radiology, Eulji University, School of Medicine, Daejon, Korea.