1. From the Department of Radiology (T.U., Y. Ohno, S.H., Y.T., Y. Obama, H.I., H.T.) and Joint Research Laboratory of Advanced Medical Imaging (Y. Ohno, K.M.), Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake 470-1192, Japan; and Canon Medical Systems Corporation, Otawara, Japan (K.Y., M.I., M.Y.).