1. From the Departments of Diagnostic and Interventional Radiology (T.M.V., C.H., J.A.L.) and Pediatric Cardiology (C.H.), University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, Germany; and Quantitative Imaging Laboratory Bonn (QILaB), Bonn, Germany (T.M.V., J.A.L.).