P189 Diffusion-weighted magnetic resonance enterography for prediction of response to tumour necrosis factor inhibitors in stricturing Crohn’s disease

Abstract

Patients with Crohn’s disease (CD) frequently develop intestinal strictures that are a major cause of surgical and endoscopic interventions. Predominantly fibrotic strictures are less likely to respond to anti-inflammatory therapy. None of the currently available diagnostic modalities can reliably distinguish between fibrotic and inflammatory strictures. The capacity of diffusion-weighted (DWI) magnetic resonance (MRE) to identify intestinal fibrosis was recently demonstrated; however the therapeutic implications of this association have never been evaluated. The aim of the current study was to identify the imaging factors associated with response to anti-inflammatory treatment in patients with stricturing CD. Consecutive CD patients with intestinal strictures that initiated treatment with anti-tumour necrosis alpha (anti-TNF) between June 2012 and April 2017 with MRE adjacent to treatment ONSET were retrospectively collected. Patients with previous intestinal surgery or active penetrating complications on index MRE were excluded. The primary outcome was treatment failure, defined as drug discontinuation, CD-related surgery or endoscopic dilatation of the stricture. Clinical, demographic and imaging parameters including stricture length, prestenotic dilatation diameter, presence of ulcers, apparent diffusion coefficient (ADC), relative contrast enhancement (RCE), magnetic resonance index of activity (MaRIA) and Clermont score were compared between patients who did and did not develop treatment failure within 12 months of anti-TNF treatment. A total of 21 patients were included in the study; 9/21 (42.8) developed treatment failure. None of the clinical and demographic variables were associated with the likelihood of treatment failure. Among imaging parameters, only ADC (<1 x 10–3 mm2/s) was significantly associated with the risk of treatment failure (66% vs. 0%, p = 0.015, OR-30.1 (95% CI −1.2–785, AUC = 0.81). Our results suggest that ADC value on DWI MRE can predict the risk of treatment failure in stricturing CD. If replicated in larger studies, these results may guide therapeutic decisions and suggest avoiding anti-TNF treatment in patients with intestinal strictures with ADC <1 × 10–3 mm2/s.