From the Department of Informatics, Ionian University, Kerkyra, Greece (G.E.K., T.E.); Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, 115 27 Athens, Greece (G.E.K., T.P., P.K., C.D.A.); CMR Unit, Royal Brompton Hospital, London, England (A.S.A.); Department of Mechanical Engineering and Aeronautics, University of Patras, Patras, Greece (T.P.); Department of Materials Science and Engineering University of Ioannina, Ioannina, Greece (P.S., D.I.F.); Department of Informatics and Telecommunications, National and Kapodistrian University of Athens, Athens, Greece (P.K.); Biomedical Research Institute-FORTH, Ioannina, Greece (A.S.); Cardiothoracic and Vascular Department, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy (R.L.); Division of Imaging Sciences and Biomedical Engineering, King's College London, London, England (A.T.); Cardiac Imaging (P.A.K.) Department of Nuclear Medicine (A.G.), University Hospital Zurich, Zurich, Switzerland (A.G.); Department of Cardiology, Heart Lung Center, Leiden University Medical Centre, Leiden, the Netherlands (A.J.H.A.S.); Institute of Clinical Physiology, National Research Council-CNR, Pisa, Italy (O.P., D.N.); Institute of Information Science and Technologies, National Research Council-CNR, Pisa, Italy (O.P.); PET Center, University Hospital and University of Turku, Turku, Finland (J.K.); Cardiovascular Department, Fondazione Toscana G. Monasterio, Pisa, Italy (D.N.); and Sant'Anna School of Advanced Studies, Pisa, Italy (D.N.).