1. Medical Systems Research & Development Center, FUJIFILM Healthcare Corporation, Kashiwa, Chiba, Japan
2. Diagnostic Radiology, Hiroshima University, Hiroshima, Hiroshima, Japan
3. Medical Systems Research & Development Center, FUJIFILM Corporation, Minato-ku, Tokyo, Japan
4. Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, Hiroshima, Japan