1. From the Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (G.-M.K.); Department of Radiology, A.A. Martinos Center for Biomedical Imaging (G.-M.K., K.-Y.P., R.A., J.H., B.R., H.A.) and Department of Neurology, Stroke Service (N.R., J.R., H.A.), Massachusetts General Hospital, Harvard Medical School, Boston; and Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea (K.-Y.P.).