1. Hospital Universitari Vall d´Hebron, Department of Cardiology, CIBER-CV. Vall d’Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Spain (A.G., J.R.-P., L.G.-G., G.T.-T., A.S.A., A.E.).
2. Departments of Medical Physics & Radiology, University of Wisconsin, Madison (K.M.J., O.W.).