1. From the Department of Radiology and Research Institute of Radiology (J.Y., Y.A., S.Y.O., S.M.L., J.B.S.) and Department of Convergence Medicine (K.C., N.K.), University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Korea.