Diffusion-weighted magnetic resonance enterocolonography in predicting remission after anti-TNF induction therapy in Crohn's disease

Abstract

Background: Diffusion-weighted magnetic resonance entero-colonography (DW-MREC) with no rectal distension and with no bowel cleansing is accurate to assess inflammatory activity in ileocolonic Crohn's disease (CD).

Aim: To study DW-MREC parameters as predictors of remission (CDAI < 150 and CRP < 5mg/L) after anti-TNF induction therapy.

Methods: Forty consecutive CD patients were prospectively and consecutively included. All the patients underwent DW-MREC with apparent diffusion coefficient (ADC) and MaRIA calculation before starting anti-TNF. Mean ADC was defined as the mean of the segmental ADC.

Results: Twenty patients (50.0%) experienced remission at W12. Low mean ADC (2.05 ± 0.22 vs 1.89 ± 0.25, p = 0.03) and high total MaRIA (39.2 ± 16.6 vs 51.7 ± 18.2, p = 0.03) were predictive of remission at W12. Using a ROC curve, we determined a mean ADC of 1.96 as predictive cut-off of remission at W12 (AUC = 0.703 [0.535-0.872]) with sensitivity, specificity, positive predictive value and negative predictive value of 70.0%, 65.0%, 66.7% and 68.4%, respectively. In multivariate analysis, mean ADC < 1.96 (OR = 4.87, 95% CI [1.04-22.64]) and total MaRIA > 42.5 (OR = 5.11, 95% CI [1.03-25.37]), reflecting high inflammatory activity, were predictive of remission at week 12.

Conclusions: DW-MREC using quantitative parameters i.e. ADC, is useful in detecting and assessing inflammatory activity but also to predict efficacy of anti-TNF induction therapy in CD.

Keywords: Anti-TNF; Crohn's disease; Diffusion-weighted MRI; Predictive factor.