About the Author: Andrea Rockall is Professor of Radiology, Imperial College, London Andrew Hatrick is Consultant General and Interventional Radiologist, Frimley Park Hospital NHS Foundation Trust Peter Armstrong is formerly Professor of Radiology, Medical College of St Bartholomew's and the Royal London Hospitals, London, and formerly Professor and Vice-Chairman, University of Virginia, Charlottesville Martin Wastie is formerly Professor of Radiology, University of Malaya Medical Centre, Kuala Lumpur, and formerly Consultant Radiologist, University Hospital, Nottingham