TRansmural hEaliNg Definition in CroHn's Disease (TRENCH 1)

• ≥ 18 years of age
• Patient diagnosed with CD for more than 6 months with histological confirmation available in his medical record.
• Indication for MRE based on routine clinical practice validated by the treating physician
• Any CD treatment will be authorized, such as biologicals (infliximab, adalimumab, vedolizumab, ustekinumab...), or immunomodulators (azathioprine, 6-mercaptopurine, methotrexate...).
• The subjects sign and date a written, informed consent form and any required privacy authorization prior to the initiation of the study.
• A subject can be enrolled into the study only if the grade of TH (assessed by the LRP) corresponding to the subject is not already fulfilled.

Exclusion Criteria:

• Pregnancy during the study
• People unable to give consent (because of their physical or mental state)
• Absence of written consent
• Ulcerative colitis or unclassified IBD
• Specific postsurgical settings: ileoanal anastomosis, ileostomy or colostomy.
• Less than 3 evaluable ileocolic segments or more than 3 resected ileocolonic segments (not counting ileocecal valve)
• Severe obstructive symptoms
• Symptomatic intra-abdominal abscess
• Contraindication for MRI
• Isolated perianal disease without luminal location
• MRE images of poor quality, based on previously defined criteria