Introduction Advances in therapy and definitions of inflammatory bowel disease (IBD) control have led to increasing reliance on imaging. Awareness of effects of ionising radiation has placed emphasis on radiation-free imaging. We assessed the role of magnetic resonance enterography (MRE) in small bowel Crohn’s disease (CD).

Methods We conducted a retrospective review of 948 MRE studies between June 2009 and December 2012 at our institution. Clinical data (demographics, disease characteristics and therapy) were obtained from electronic record review. Inflammatory markers, radiological tests and ileocolonoscopy within 90 days of MRE were recorded. MRE reports were recorded using accepted activity criteria- small bowel dilatation, stenosis, wall thickening, enhancement, mucosal irregularity, mesenteric inflammation, hypervascularity, lymph node enlargement, abscesses, fistulation and extraintestinal features.

Results Of 455 patients with IBD, 385 had CD (224 of these female; mean age 36;range 12–72 and median disease follow up 4 years (range 0–39).

Abnormalities were noted in 285 scans; 162 had active non-stricturing, 109 active stricturing and 13 fibrostenotic disease. Within active groups, there were 29 fistulae and 12 abscesses in 33 patients. Ileo-colonoscopy was performed in 70 patients with active non-stricturing disease with 57/70 showing active colitis and raised CRP in 65/146. Treatment was increased in 55% of the active non-stricturing group, 28/89 to azathioprine, 24/89 to infliximab, 10/89 to surgery, 14/89 had 5 -ASA with no change in 45%, of whom 12/39 had normal ileo-colonoscopy and 54/68 normal CRP.

In 50% of active stricturing group, treatment was increased to azathioprine in 11, biologics (25) and 17 to surgery. Thirty-eight of 82 patients in the group had an elevated CRP and 23/39 active colitis at ileo-colonoscopy.

Of 99 normal MRE, treatment was unchanged in 96%; with normal CRP in 68/87 and ileo-colonoscopy in 17/38.

Of 13 fibrostenotic subjects, 9 had normal CRP and 6 had mild colitis at colonoscopy. Four had surgery and 1 had endoscopic dilatation of a stricture while 5 had no change as MRE showed improved appearances (2 commenced steroids and 1 changed to adalimumab). In the abscess/fistula group 6 were referred for surgery, 6 had infliximab (fistula), 2 had adalimumab (fistula), 2 had azathioprine (fistula) and 4 were treated with antibiotics.

Conclusion The small bowel remains difficult to assess endoscopically. The choice of investigation will be driven by the clinical question, available expertise and economic factors. MRE aids assessment of CD, in addition to endoscopy and biological markers identifying patients with active disease for meaningful treatment escalation.

Disclosure of Interest None Declared.