 To date, it is very difficult to quantify inflammation in patients with pCD due to the absence of reliable disease activity measurements. In addition to this, optimising therapies for pCD is quite challenging and may have a major impact on quality of life. Magnetic resonance imaging of pelvic is a standard examination for the anatomical evaluation of pCD which is significant in terms of surgical therapy and progress. The overall hypothesis is that newer MRI techniques such as magnetization transfer MT, diffusion weighted image DWI and dynamic contract enhancement DCE are better suited to measuring the inflammatory vs fibrotic burden in pCD. The aim of this project is to measure disease activity within pCD and luminal CD using MRI sequences before and after biological therapy 