1. From the Department of Radiology, Seoul National University Hospital and Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul 03080, Korea (S.K.J., J.M.L., I.J., J.H.Y.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.L.); and Ultrasound R&D 2 Group, Health & Medical Equipment Business, Samsung Electronics Co, Ltd, Seoul, Korea (G.L.).