[1] Addenbrookes Hosp, Dept Radiol, Cambridge, England
[2] Univ Cambridge, Cambridge, England
[3] Radboud Univ Nijmegen Med Ctr, Dept Med Imaging, Nijmegen, Netherlands
[4] Univ Coll London Hosp NHS Fdn Trust, Dept Radiol, London, England
[5] UCL, Div Surg & Intervent Sci, London, England
[6] Mt Vernon Hosp, Paul Strickland Scanner Ctr, Northwood, Middx, England