[1] Daerim St Marys Hosp, Thyroid Ctr, Dept Radiol, Seoul 150070, South Korea
[2] Univ Ulsan, Coll Med, Asan Med Ctr, Dept Radiol, Seoul, South Korea
[3] Sungkyunkwan Univ, Sch Med, Samsung Med Ctr, Dept Radiol, Seoul, South Korea
[4] Daerim St Marys Hosp, Thyroid Ctr, Dept Internal Med, Seoul 150070, South Korea