1. From the Department of Radiology and Research Institute of Radiology (S.P., S.M.L., K.H.D., J.B.S.); Department of Medical Statistics (S.K.), Department of Convergence Medicine (J.G.L.), and Department of Cardiothoracic Surgery (S.C.), University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43 Gil, Songpa-gu, Seoul 138-736, Korea.