1. From the Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan (H.O., M.H., T.O., A.N., K.O., M.T., H.F., N.T.); Canon Medical Systems, Otawara, Japan (S.T., A.U., Y.S., A.T.); and Division of Radiology, Department of Medical Technology, Osaka University Hospital, Suita, Japan (Y.E., K.S.).