1. From the Departments of Neurology (J.-W.C., O.Y.B., M.J.L., J.H.) and Radiology (J.C., Y.H.C.), Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; and Department of Medicine, Cardiovascular Imaging Center, Cardiac and Vascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea (J.-H.C.).