1. Department of Radiology, Chungbuk National University Hospital, Cheongju, South Korea
2. Department of Radiology, College of Medicine, Chungbuk National University, Cheongju, South Korea
3. Department of Urology, College of Medicine, Chungbuk National University, Cheongju, South Korea
4. Department of Urology, Chungbuk National University Hospital, Cheongju, South Korea.