Two thirds of patients with Crohn's disease require intestinal surgery at some time in their life. Intestinal strictures, that is narrowing of the bowel due to inflammation and scarring, are the most common reason for surgery. Despite the high frequency, associated disability, and cost there are no are no treatment strategies that aim to improve the outcome of this disease complication. The STRIDENT (stricture definition and treatment) studies aim to determine biochemical and imaging features associated with the development of strictures and in related STRIDENT studies develop strategies for treatment.