1. From the Departments of Radiology and Research Institute of Radiology (P.-H.L., J.W.P., S.C.P., J.L.K., D.H.L., D.C.S.), the Department of Neurology (S.U.K., J.S.K.), and the Division of Biostatistics (S.-C.Y.), Center for Medical Research and Information, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea; and the Department of Radiology (P.-H.L.), JiangSu Province SuBei Hospital, First Affiliated Hospital of Yangzhou University, Yangzhou, People's Republic of China.