1. Department of Urology, Niigata University Medical and Dental Hospital, Niigata, Japan.
2. Department of Gastroenterology, Niigata University Medical and Dental Hospital, Niigata, Japan.
3. Department of Diagnostic Radiology, Niigata University Medical and Dental Hospital, Niigata, Japan.
4. Pathology, Uonuma Institute of Community Medicine, Niigata University Medical and Dental Hospital, Niigata, Japan.