[1] Seoul Natl Univ, Boramae Hosp, Dept Neurol, Seoul 156707, South Korea
[2] Seoul Natl Univ, Boramae Hosp, Dept Neurosurg, Seoul 156707, South Korea
[3] Seoul Natl Univ Hosp, Dept Radiol, Seoul 110744, South Korea
[4] Kwandong Univ, Myungji Hosp, Coll Med, Dept Neurol, Goyang, South Korea