1FMRIB Centre, University of Oxford, Oxford, United Kingdom, 2Electrical and Computer Engineering, Brigham Young University, Provo, UT, United States, 3Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom, 4Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 5Icahn School of Medicine at Mount Sinai, New York, NY, United States, 6Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany, 7Siemens Healthcare (UK), London, United Kingdom, 8UK Biobank Ltd, Stockport, United Kingdom, 9Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom, 10Department of Medicine, Imperial College London, London, United Kingdom