1. Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Kurashiki City, Okayama, Japan
2. Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
3. Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
4. Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
5. Department of Diagnostic Radiology, Tsuchiya General Hospital, Naka-ku, Hiroshima, Japan
6. Department of Cardiovascular Internal Medicine, Edogawa Hospital, Tokyo, Japan.