T D Westwood1, P Capozzi2, D F Martin1, S A Sukumar3. 1. Department of Radiology, University Hospital South Manchester NHS Trust, Greater Manchester, UK. 2. Department of Colorectal Surgery, University Hospital South Manchester NHS Trust, Greater Manchester, UK. 3. Department of Radiology, University Hospital South Manchester NHS Trust, Greater Manchester, UK. Electronic address: Sathi.Sukumar@uhsm.nhs.uk.