Radiological Sciences, Mental Health and Clinical Neuroscience, University of Nottingham, Nottingham, United Kingdom. National Institute for Health Research Nottingham Biomedical Research Centre, Nottingham, United Kingdom. Stroke Trials Unit, Mental Health and Clinical Neuroscience, University of Nottingham, Nottingham, United Kingdom. Stroke, Nottingham University Hospitals National Health Service (NHS) Trust, Nottingham, United Kingdom. Imaging Department, Leicester Royal Infirmary, Leicester, United Kingdom. National University of Malaysia, Kuala Lumpur, Malaysia. Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom. London School of Hygiene and Tropical Medicine, London, United Kingdom. Stroke Research Centre, University College London Queen Square Institute of Neurology, London, United Kingdom. Department of Stroke, University Hospitals of Derby and Burton NHS Foundation Trust, Derby, United Kingdom. Medical Physics and Clinical Engineering, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom. Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom.