Introduction NICE guidelines mandate yearly reassessment of disease activity for those treated with anti-TNF therapy (ATT). Magnetic resonance enterography (MRE) is established in the assessment of small bowel Crohn’s disease, however, there is little data to support its utility in disease monitoring. We examined MRE prior to treatment and after at least 6 months treatment with ATT, observing for radiological remission or change in disease burden.

Methods We identified 27 patients (infliximab n = 23 adalimumab n = 4) who underwent pre-treatment and reassessment MRE from a local database of patients treated with ATT. MRE scans were assessed by a consultant radiologist, measuring location of lesions, number of skip lesions, length of affected small bowel and skip lesion wall thickness.

Results Median time to MRE post initiation of ATT was 12 months (range 6–20). All patients were ATT naïve prior to treatment; all but 2 were treated with concomitant immunosuppression. In 63% (n = 17) of patients, there was small bowel disease noted in > 1 location; terminal ileum 74% (20), distal ileum 37% (10), mid ileum 22% (6), proximal ileum 18% (5), distal jejunum 15% (4), mid jejunum 4% (1) and duodenum 4% (1). In no instances had disease spread to a new location on interval scanning. Total length of involvement (cm) improved post-treatment from median 15cm (range 3–50) to 6.8cm (0–33) p = 0.012, as did length of the dominant lesion 6.5cm (2.5–30) vs 3cm (0–30) p = 0.001. Lesion bowel wall thickness also improved 7mm (4–12) vs 5mm (2–10) p = 0.0006. Disease burden, calculated by total stricture length x bowel wall thickness, also improved, 80 (12–400) vs 32 (0–264) p = 0.001. Improvement in number of skip lesions per-patient was not significant 2 (1–6) vs 1 (0–5) p = 0.2; in 2 cases the number of skip lesions increased. In no cases was the total length of involvement greater; however in 27% (7) cases this was static, and in 11% (3) bowel wall thickness was greater. Total disease burden was greater in 2 patients. Complete radiological remission was demonstrated in only 2 patients.

Conclusion Response of Crohn’s disease to ATT is well documented, and we are able to demonstrate quantifiable interval improvement using MRE. Recording the disease burden by way of stricture length and bowel wall thickness is a mode of measuring MRE response to treatment in Crohn’s disease and may be used for disease reassessment as required by NICE.

Disclosure of Interest None Declared.