[1] Seoul Natl Univ, Dept Neurol, Coll Med, Seoul, South Korea
[2] Seoul Natl Univ, Dept Nucl Med, Coll Med, Seoul, South Korea
[3] Seoul Natl Univ Hosp, Clin Res Inst, Seoul 110744, South Korea
[4] Juntendo Univ, Coll Med, Dept Neurol, Tokyo 113, Japan