Free water elimination using a bi-tensor model improves test-retest reproducibility of diffusion tensor imaging indices in the brain:  a longitudinal multisite reliability study of healthy elderly subjects

¹Center for Mind/Brain Sciences (CIMEC), University of Trento, Rovereto, Trento, Rovereto (Trento), Italy, ²Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, Boston, MA, United States, ³Scientific Department, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy, Milan, Italy, ⁴LENITEM Laboratory of Epidemiology, Neuroimaging, & Telemedicine — IRCCS San Giovanni di Dio-FBF, Brescia, Italy, Brescia, Italy, ⁵Memory Clinic and LANVIE, Laboratory of Neuroimaging of Aging, University Hospitals and University of Geneva, Geneva, Switzerland, Geneva, Switzerland, ⁶Department of Psychiatry and Clinical Psychobiology, Universitat de Barcelona and IDIBAPS, Barcelona, Spain, Barcelona, Spain, ⁷Department of Neuroradiology and Magnetic Resonance Image core Facility, Hospital Clínic de Barcelona, IDIBAPS, Barcelona, Spain, Barcelona, Spain, ⁸Alzheimer's Disease and Other Cognitive Disorders Unit, Department of Neurology, Hospital Clínic, and IDIBAPS, Barcelona, Spain, Barcelona, Spain, ⁹Deptartment Geriatrics, Neuroscience & Orthopaedics, Catholic University, Policlinic Gemelli, Rome, Italy, Rome, Italy, ¹⁰IRCSS S.Raffaele Pisana, Rome, Italy, Rome, Italy, ¹¹Center for Neuropsychological Research, Catholic University, Rome, Italy, Rome, Italy, ¹²LVR-Clinic for Psychiatry and Psychotherapy, Institutes and Clinics of the University Duisburg-Essen, Essen, Germany, Essen, Germany, ¹³Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg August University, Göttingen, Germany, Göttingen, Germany, ¹⁴Department of Neuroradiology, IRCSS San Martino University Hospital and IST, Genoa, Italy, Genoa, Italy, ¹⁵Department of Health Sciences, University of Genoa, Genoa, Italy, Genoa, Italy, ¹⁶Department of Neuroscience, Ophthalmology, Genetics and Mother–Child Health (DINOGMI), University of Genoa, Genoa, Italy, Genoa, Italy, ¹⁷Pharmacology, Assistance Publique — Hôpitaux de Marseille, Aix-Marseille University — CNRS, UMR 7289, Marseille, France, Marseille, France, ¹⁸CRMBM–CEMEREM, UMR 7339, Aix Marseille Université — CNRS, Marseille, France, Marseille, France, ¹⁹APHM, CHU Timone, Service de Neurologie et Neuropsychologie, Marseille, France, Marseille, France, ²⁰Aix Marseille Université, Inserm, INS UMR_S 1106, 13005, Marseille, France, Marseille, Italy, ²¹Université de Lille, Inserm, CHU Lille, U1171 - Degenerative and vascular cognitive disorders, F-59000 Lille, France, Lille, France, ²²INSERM, Imagerie cérébrale et handicaps neurologiques, UMR 825, Toulouse, France, Toulouse, France, ²³Université de Toulouse, UPS, Imagerie cérébrale et handicaps neurologiques, UMR 825, CHU Purpan, Place du Dr Baylac, Toulouse Cedex 9, France, Toulouse, France, ²⁴Department of Neuroradiology, General Hospital, Verona, Italy, Verona, Italy, ²⁵Department of Neuroscience Imaging and Clinical Sciences, University “G. d'Annunzio” of Chieti, Italy, Chieti, Italy, ²⁶Institute for Advanced Biomedical Technologies (ITAB), University “G. d'Annunzio” of Chieti, Italy, Chieti, Italy, ²⁷IRCCS SDN, Naples, Italy, Naples, Italy, ²⁸University of Naples Parthenope, Naples, Italy, Naples, Italy, ²⁹Section of Neurology, Centre for Memory Disturbances, University of Perugia, Perugia, Italy, Perugia, Italy, ³⁰Medical Physics Unit, Perugia General Hospital, Perugia, Italy, Perugia, Italy, ³¹Neuroradiology Unit, Perugia General Hospital, Perugia, Italy, Perugia, Italy, ³²3rd Department of Neurology, Aristotle University of Thessaloniki, Thessaloniki, Greece, Thessaloniki, Greece, ³³Interbalkan Medical Center of Thessaloniki, Thessaloniki, Greece, Thessaloniki, Greece, ³⁴Interbalkan Medical Center of Thessaloniki, Thessaloniki, Greece Department of Radiology, Aristotle University of Thessaloniki, Thessaloniki, Greece, Thessaloniki, Greece