Description of the Radiological Response of Anoperineal Fistulizing Lesions of Crohn's Disease

Patients selected retrospectively will have benefited from an MRI at diagnosis and a control MRI during follow-up. They will be selected during a follow-up consultation or a biotherapy injection in a day hospital. Patients selected consecutively are monitored at the Rouen University Hospital for perineal Cohn's disease, treated with Biotherapy: Infliximab, Adalimumab, Ustekinumab, Vedolizumab.