From the Department of Radiology, the Institute of Medical Science, the University of Tokyo (K.Y., H.A., A.K.); Department of Radiology, Graduate School of Medicine, the University of Tokyo (O.A.); and Department of Radiology, Graduate School of Medical Sciences, International University of Health and Welfare, 4-3 Kozunomori, Narita, Chiba, Japan 286-8686 (S.K.). (2018-04時点)