From the Departments of Radiology (A. M. Tokumaru, I. Sakata, T. Kaji, S. Kohyama, and S. Kusano), and Internal Medicine (K. Kamakura), National Defense Medical College, Saitama, Department of Neurology, Kameda Medical Center, Chiba (T. Maki and S. Hasegawa), and Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Tokyo (S. Murayama), Japan.