1. Department of Radiology, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Box 218, Level 5, Hills Road, Cambridge, CB2 0QQ, UK
2. Cambridge Vascular Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB2 0QQ, UK
3. Department of Surgery, Changi General Hospital, Singapore
4. Department of Vascular Surgery, Norfolk & Norwich University Hospital, Norwich, NR4 7UY, UK