1. Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
2. Department of Radiology, Kawasaki Medical School, Kurashiki 701-0192, Japan.
3. Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
4. Department of Urology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.