1 Department of Radiology, Royal Victoria Infirmary, Newcastle upon Tyne, UK. Electronic address: andrewyeung@hotmail.com.
2 Department of Biochemistry, University of Cambridge, Cambridge, UK; Cancer Research UK Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
3 Department of Radiology, Southmead Hospital, Bristol, UK.
4 Department of Radiology, Morriston Hospital, Swansea, UK.