[1] Yonsei Univ, Coll Med, Severance Childrens Hosp, Dept Urol, 50-1 Yonsei Ro, Seoul 120752, South Korea
[2] Yonsei Univ, Coll Med, Severance Childrens Hosp, Urol Sci Inst, 50-1 Yonsei Ro, Seoul 120752, South Korea
[3] Yonsei Univ, Coll Med, Severance Childrens Hosp, Dept Radiol, 50-1 Yonsei Ro, Seoul 120752, South Korea
[4] Yonsei Univ, Coll Med, Severance Childrens Hosp, Res Inst Radiol Sci, 50-1 Yonsei Ro, Seoul 120752, South Korea
[5] Yonsei Univ, Coll Med, Biostat Collaborat Unit, 50-1 Yonsei Ro, Seoul 120752, South Korea