Naoko Mori1, Shunji Mugikura2,3, Kei Takase2. 1. Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, Seiryo 1-1, 980-8574, Sendai, Japan. naokomori7127@gmail.com. 2. Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, Seiryo 1-1, 980-8574, Sendai, Japan. 3. Division of Image Statistics, Tohoku Medical Megabank Organization, Tohoku University, Seiryo 2-1, 980-8574, Sendai, Japan.