1. From the Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea (H.K., S.H.Y.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (H.K., S.H.Y.); and Medical Research Collaborating Center, Seoul National University Hospital, Seoul, Korea (H.H.).