1. Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjyo, Chuo-ku, Kumamoto 860-8556, Japan
2. Department of Central Radiology, Kumamoto University Hospital, 1-1-1 Honjyo, Chuo-ku, Kumamoto 860-8556, Japan
3. Department of Cardiovascular Medicine, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjyo, Chuo-ku, Kumamoto 860-8556, Japan