1. From the Department of Radiology (Y.Y.K., M.J.K., C.A.) and Biostatistics Collaboration Unit, Department of Biomedical Systems Informatics (E.H.K., Y.H.R.), Severance Hospital, Yonsei University College of Medicine, Seodaemun-gu Yonsei-ro 50-1, Seoul 03722, Republic of Korea.