 The majority of published studies have been carried out at 1.5T. The 3T scanners available at the Universities of Nottingham,London and Manchester will provide better resolution and sensitivity allowing us to design better clinical protocols incorporating quantitative MRI. 3T MR scanners are available in National Health ServiceNHS trusts but are not routinely used for the assessment of pCD. Our aim is to develop an optimized protocol for 3T imaging although we expect that our results will also be able to improve 1.5T imaging. This work will create a paradigm shift in the radiological monitoring of disease activity in pCD. 