1. Department of Rehabilitation Medicine, Tokyo Bay Rehabilitation Hospital, Chiba 275-0026, Japan
2. Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan
3. Department of Biostatistics, Faculty of Medicine, University of Tsukuba, Ibaraki 305-8577, Japan
4. Department of Radiology, Yatsu Hoken Hospital, Chiba 275-0026, Japan