Since 2009, many studies tend to prove the effectiveness of diffusion-weighted MR-enterography in the assessment of inflammatory activity in IBD compared to standard MR-enterography, with the emergence of new radiological scores such as the Clermont score. Diffusion-weighted MRI (DWI) is a faster technique and does not require the injection of gadoline contrast medium, which is a desirable in view of recent data on their long-term adverse effects (intracerebral deposits, nephrogenic systemic fibrosis).

The advent of 3T MRI, which provides a better signal, a better spatial resolution or the same examination quality in a shorter time, seems promising for the future of DWI.

However, to date, there are still few studies carried out at 3T in this field or even few studies on the possibility of doing away with bowel cleansing, although this is one of the main demands of patients. All patients will undergo a simplified MR-enterography, which includes four sequences, without bowel cleansing or injection. On the same day, the standard MR-enterography will be performed as in clinical practice, after ingestion of the usual oral preparation.

Three reading sessions of the examination will be organized at intervals of at least one month by two radiologists specialized in digestive imaging, blinded to the clinical and

Inclusion Criteria:

• Any patient diagnosed with Crohn's disease with bowel involvement for whom a MR-enterography was ordered as part of their follow-up
• Age ≥ 18
• Subject's ability to understand and express opposition
• Affiliation to French social security system

Exclusion Criteria:

• Any contraindication to MRI
• Allergy to gadolinium chelates
• Claustrophobia
• Major obesity that does not allow the patient to enter the machine's tunnel (whose diameter is 70 cm)
• Pregnant woman
• Person under curators or guardianship