[1] Kings Coll London, St Thomas Hosp, Sch Biomed Engn & Imaging Sci, London SE1 7EH, England
[2] Kings Coll Hosp London, Dept Neurosurg, Denmark Hill, London SE5 9RS, England
[3] St Thomas Hosp, Dept Cardiothorac Surg, Lambeth Palace Rd, London SE1 7EH, England