Affiliation: | (1) Department of Radiology, Royal Hallamshire Hospital, Glossop Road, S10 2JF Sheffield, UK;(2) Department of Vascular Surgery, Royal Hallamshire Hospital, Glossop Road, S10 2JF Sheffield, UK;(3) Department of Radiology, National Hospital for Neurology, Queen Square, WC1N 3BG London, UK |