1. From the Department of Radiology and Research Institute of Radiology, Cardiac Imaging Center (H.J.K., J.W.K., D.H.Y.), Division of Cardiology, Internal Medicine, Cardiac Imaging Center (S.A.L.), and Department of Thoracic and Cardiovascular Surgery (S.H.J.), University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, South Korea.