P418. Magnetic resonance enterography demonstrates response to anti-TNF therapy in small bowel Crohn's disease
R. Dart1,2, N. Griffin3, V. Goh3, K. Taylor1,2, S. Anderson1, J. Sanderson1,2, P. Irving1,2, 1St Thomas' Hospital, Department of Gastroenterology, London, United Kingdom, 2King's College, University of London, Nutritional Sciences Division, United Kingdom, 3St Thomas' Hospital, Department of Radiology, London, United Kingdom
The importance of mucosal healing in Crohn's disease is becoming increasingly realised. Assessing the activity and extent of small bowel Crohn's disease endoscopically is challenging, hence radiological assessment is preferred. Magnetic resonance enterography (MRE) is often used instead of CT because of the risks of radiation exposure. We examined the effects of anti-TNF therapy (ATT) on disease activity and extent as assessed by interval MRE.
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 reviewed by a consultant radiologist, measuring location of lesions, number of skip lesions, length of affected small bowel and lesion wall thickness. Statistical analysis was performed with Excel.
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% (17) 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 15 cm (3–50) to 6.8 cm (0–33) p = 0.012, as did length of the dominant lesion 6.5 cm (2.5–30) vs 3 cm (0–30) p = 0.001. Lesion bowel wall thickness also improved 7 mm (4–12) vs 5 mm (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 2 patients.
Response of Crohn's disease to ATT is well documented although there is limited evidence on the role of MRE to assess the response to treatment. Small bowel Crohn's disease is difficult to assess endoscopically and the role of biomarkers is less well understood than, for example, in colonic disease. This study supports the utility of MRE in assessment of small bowel Crohn's disease and its response to treatment.