P369 Diffusion-Weighted magnetic resonance enterocolonography before treatment predicts remission after anti-TNF therapy in Crohn's disease
A. Buisson*1, 2, C. Hordonneau3, M. Goutte1, 2, J. Scanzi1, F. Goutorbe1, T. Klotz3, L. Boyer3, B. Pereira4, G. Bommelaer1, 2
1University Hospital Estaing, Gastroenterology Department, Clermont-Ferrand, France, 2UMR 1071 Inserm/Université d'Auvergne; USC-INRA 2018, Microbes, Intestine, Inflammation and Susceptibility of the host, Clermont-Ferrand, France, 3University Hospital Estaing, Radiology Department, Clermont-Ferrand, France, 4GM – Clermont-Ferrand University and Medical Center, , Biostatistics Unit , Clermont-Ferrand, France
Almost one third of the Crohn's disease (CD) patients experienced primary failure to anti-TNF therapy. Owing to the cost and the potential side effects, determining predictors of anti-TNF efficacy remains a key point in clinical practice. Diffusion-weighted magnetic resonance entero-colonography (DW-MREC) without rectal distension and without bowel cleansing has shown good accuracy to detect and assess inflammatory activity in CD  .
We aimed to study DW-MREC parameters as predictors of clinical response (delta CDAI > or = 100), remission (defined as CDAI<150 AND CRP<5 mg/L) and surgery at week 12 after anti-TNF therapy.
Overall, 40 consecutive CD patients were prospectively and consecutively included. All the patients underwent a DW-MREC   within 4 weeks before starting anti-TNF. Adalimumab was administered as 160mg at W0, 80mg at W2 and 40mg every other week. Infliximab was administered as 5mg/kg at W0, W2 and W6. The collected MRI parameters were reported in Table 1.
Table 1 “MRI parameters collected for the study”
MRI data and population characteristics are given in Table 1 and 2, respectively.
Table 2 “Population characteristics (n=40)”
Overall, 25 patients (67.5%) achieved clinical response at week 12. High Clermont score value   (27.2+/-8.4 vs 21.4+/-9.4, p=0.05) and active active segments defined as ADC<1.9(47.8% vs 82.4%, p=0.03) were predictive of clinical response at week 12.
Overall, 20 patients (50.0%) experienced remission at week 12. Low mean ADC value (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 deep remission at week 12. Using a ROC curve, we determined a mean ADC of 1.96 as predictive cut-off of remission at week 12 (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.
No MRI factors were predictive of surgery at week 12.
ADC value and Clermont score retrieved from DW-MREC, reflecting the inflammatory activity, predict response and remission after anti-TNF therapy in CD. DW-MREC is useful in detecting and assessing inflammatory activity in CD but also in predicting efficacy of anti-TNF induction therapy.
 Buisson A et al., (2013), Diffusion-weighted magnetic resonance imaging for detecting and assessing ileal inflammation in Crohn's disease, Aliment Pharmacol Ther
 Hordonneau C et al., (2014), Diffusion-Weighted Magnetic Resonance Imaging in Ileocolonic Crohn ' s Disease: Validation of Quantitative Index of Activity, Am J Gastroenterol