[1] YongDong Severance Hosp, Dept Diagnost Radiol, Kangnam Ku, Seoul 135270, South Korea
[2] Yonsei Univ, Coll Med, Dept Diagnost Radiol, Shinchon Severence Hosp,Seodaemun Ku, Seoul 120757, South Korea
[3] Yeungnam Univ, Coll Med, Dept Diagnost Radiol, Nam Ku, Taegu 705035, South Korea