Background: Endoscopic mucosal healing should be the therapeutic goal in Crohn's disease (CD) as it is associated with more favourable outcomes. Alternative non-invasive approach, such as magnetic resonance imaging (MRI), is able to detect morphologic changes under therapy . However, whether achieving MRI remission is associated with favourable outcomes remains unknown.
We aimed to investigate whether MRI remission after therapeutic intervention could predict clinical corticosteroids-free remission (CFREM) and CD related-surgery.
Methods: We performed a posthoc analysis from pooled data of two prospective trials. All the patients undergoing MRI to monitor therapeutic response were included. Patients were excluded from this study if follow-up was <6 months. Objective sign of inflammation on colonoscopy, CTscan or MRI before treatment has to be available to include the patients. All the patients underwent diffusion-weighted magnetic resonance enterocolonography with no bowel cleansing and no rectal enema. MRI evaluation was performed using 5 segments (ileum, right colon, transverse colon, left/sigmoid colon and rectum). MRI remission was defined using Clermont criteria  (no segmental Clermont score >12.5) or using Barcelona criteria  (no segmental MaRIA >11). Deep MRI remission was defined as no segmental MaRIA >7 or no segmental Clermont score >8.4. Clinical CFREM was defined as absence of CD flare (=reappearance or worsening of clinical manifestation leading to therapeutic modification, hospitalization or CD-related surgery). For each of the patients CFREM were assessed by semesters.
Results: Overall, 63 patients were included (Table 1) with a median follow-up of 4 semesters.
Overall, 300 semesters were considered. In multivariate analysis taken into account the impact of CDAI, CRP and current therapy at inclusion, deep MRI remission was associated with more time spent in CFREM according to Barcelona (85.7% vs 44.9%, p=0.01)or Clermont criteria (69.3% vs 46.9%, p=0.049). MRI remission was also associated higher proportion of semester spent in CFREM according to Barcelona (66.7% vs 47.3%, p=0.042)or Clermont criteria (69.4% vs 42.7%, p=0.049). Patients achieving deep MRI remission or MRI remission had an increased time to CD-related surgery compared to those with persistent MRI activity (p<0.05, for all criteria).
Conclusions: MRI remission after therapeutic intervention is associated with favourable outcomes and should be considered as non-invasive therapeutic endpoint in CD. A dedicated prospective trial should be led to confirm our data.
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