1. Department of Urology, Hitachi, Ltd., Hitachi General Hospital, Ibaraki, Japan and Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan
2. Department of Urology, Hitachi, Ltd., Hitachi General Hospital, Ibaraki, Japan
3. Department of Urology, Hitachi, Ltd., Hitachi General Hospital, Ibaraki
4. Department of Radiology, Hitachi, Ltd., Hitachi General Hospital, Ibaraki, Japan
5. Department of Radiology, Hitachi, Ltd., Hitachi General Hospital and Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan