1. Department of Health Sciences, Hokkaido University, Sapporo, Japan
2. Department of Rheumatology, Sapporo Yamanoue Hospital, Sapporo, Japan
3. Department of Radiology, Sapporo Yamanoue Hospital, Sapporo, Japan
4. Department of Radiological Technology, Kurashiki Central Hospital, Kurashiki, Japan
5. Graduate School of Medicine, Hokkaido University, Sapporo, Japan
6. Faculty of Health Sciences, Hokkaido University, Sapporo, Japan