[1] Chung Ang Univ, Dept Neurol, Gwangmyeong Hosp, Gwangmyeong, South Korea
[2] Yonsei Univ, Dept Neurol, Coll Med, Seoul, South Korea
[3] Yonsei Univ, Coll Med, Dept Radiol, Seoul, South Korea
[4] Natl Univ Singapore, Yong Loo Lin Sch Med, Dept Diagnost Radiol, Singapore, Singapore
[5] Sungkyunkwan Univ Med, Samsung Med Ctr, Dept Radiol, Seoul, South Korea