This study aims to investigate if MR Enterography (MRE) improves the ability to predict which Crohn's disease patients will relapse quickly (disease comes back) after stopping biologic medication. MRE is a safe MRI scan of the bowel, widely used in Crohn's disease patients.

This study aims to investigate if MR Enterography (MRE) improves the ability to predict which Crohn's disease patients will relapse (disease comes back) after stopping biologic medication when clinically well. MRE is a safe MRI scan of the bowel, widely used in Crohn's disease patients.

Using a network of British Society of Gastrointestinal and Abdominal Radiology (BSGAR) affiliated NHS hospitals, up to 200 patients who have stopped biologic treatment and recently underwent MRE as part of usual care will be identified. Detailed analysis will be performed on these MRI scans using scores measuring residual bowel inflammation, and retrospectively collect standard clinical data such as blood, stool and colonoscopy results. Using hospital records (accessed by each local care team before being pseudoanonymised) the study will see what happened to patients after one year, specifically if they relapsed or remained well off the biologics.

Based on a literature review, the most promising predictors of early relapse will be identified, such as blood/stool tests, to build a statistical model that provides the risk of a patient relapsing within one year. MRE scores will be added to this model to see if it improves the ability to predict relapse.

The results of the study could form part of a clinical decision support tool to help risk stratify patients and improved joint management decision making.

Inclusion Criteria:

• Luminal small bowel or colonic Crohn's disease in clinical remission
• 16 years or older
• MRE as part of routine care performed within three months prior, or one month after the decision to stop biologic therapy Anti-TNF (Adalimumab, infliximab, Certolizumab) IL-23 or IL-12 antagonists (Ustekinumab) Anti-integrin biologics (Natalizumab, Vedolizumab)
• Biologic therapy stopped due to clinical remission only

Definition of clinical remission: There is no agreed consensus on how clinical remission is defined and practice differs between hospitals and patients. To mirror current clinical practice, no strict definition of clinical remission will therefore be used. Detailed clinical parameters the time of stopping biologic agents will be collected.

Exclusion Criteria:

<16 years of age

Non-biological therapy, unless part of combination therapy with biologic agents

Biological therapy stopped for other reasons e.g. loss of effect, side effects

Resection of diseased segment(s) after MRE but before stopping biologic agent.

No MRE with the time window defined by eligibility criteria

Crohn's disease patients will be identified after the clinical decision to stop biologics including during outpatient clinics, multidisciplinary meetings, any local patient databases, and imaging investigation requests.