1. University of Edinburgh; Division of Clinical Neurosciences; Western General Hospital Edinburgh UK EH4 2XU
2. Freeman Hospital; Department of Vascular Surgery; Newcastle upon Tyne Hospitals NHS Foundation Trust High Heaton Newcastle upon Tyne UK NE7 7DN
3. Freeman Hospital; Northern Vascular Centre; Newcastle upon Tyne UK NE7 7DN
4. The University of Sheffield; Medical Care Research Unit; 30 Regent Street Sheffield UK S1 4DA
5. University of Edinburgh; Public Health Sciences; Teviot Place Edinburgh UK EH8 9AG
6. Newcastle upon Tyne Hospital Trust; Radiology; The Freeman Hospital Newcastle upon Tyne UK NE7 7DN