Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK. NIHR Nottingham Biomedical Research Centre (BRC), Nottingham University Hospitals NHS Trust, University of Nottingham, Nottingham, UK. Division of Medicine, Centre for Medical Imaging, UCL, London, UK. Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK.