1. From the Departments of Diagnostic Radiology (S.O., M.K., Y.N., Y.Y.), Cardiovascular Medicine (S.T., H.U., K.T.), Molecular Laboratory Medicine (H.U.), and Neurology (M.U., T.Y., Y.A.), Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjyo, Chuo-ku, Kumamoto 860-8556, Japan.