1 Division of Respiratory Medicine, Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom. Electronic address: nf231@cam.ac.uk.
2 Division of Respiratory Medicine, Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
3 Institute for Lung Health, NIHR Respiratory Biomedical Research Unit, Leicester, United Kingdom.
4 Department of Nuclear Medicine, Addenbrooke's Hospital, CUHNHSFT, Cambridge, United Kingdom.
5 Division of Anaesthesia, Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
6 Division of Clinical and Laboratory Investigation, Brighton and Sussex Medical School, Brighton, United Kingdom.