Evolving modalities of small bowel imaging in Crohns disease: a retrospective audit
Introduction: Magnetic resonance (MR) imaging of the small bowel provides improved assessment of both luminal, mural and extra-mural tissue, without radiation exposure. This is an important consideration in Crohns disease (CD) due to age of onset, disease chronicity, and the need for reassessment, with MR supported by recent ECCO guidelines 1 . Uptake of MR has previously been limited by availability and cost. We sought to assess the change in small bowel imaging practice in our large tertiary referral centre.
Methods: A retrospective audit of the diagnostic imaging database at Monash Health of specific small bowel imaging (CT enteroclysis (CTE), small bowel follow-through (FT) and MR enterography and enteroclysis (MRE) from 2007-2012 was undertaken and indications for scanning, findings, and patient demographics were extracted. MR pelvis and standard CT abdomen scans were excluded.
Statistical analysis was performed using Mann-Whitney, Chi-squared and linear regression with p values of less than 0.05 considered significant.
Results: A total of 988 small bowel imaging examinations were performed. The mean age of patients was 36.6 years and 54% were female. There was a significant increase per year in MRE (r 2 =0.78, p=
0.019) with a trend for fewer follow-throughs (r 2 =0.60, p=0.069). 236 scans were for Crohns (20 CTE,
133 MRE and 83 FT). In patients with known or suspected CD, adult gastroenterologists had a highly significant increased use of MR over time compared to surgeons (17% vs 4% respectively for 2007-10
(p=0.02) compared to 86% vs 40% between 2011-12 (p<0.001)). There also was increased uptake of
MRE by paediatricians from 50% to 94% over the same period. Conversely, follow-through rates for gastroenterologists decreased more compared to the surgeons (73% vs 75% for 2007-10 to 3% vs
40% for 2011-12 (p<0.001). This discrepancy may be due to a higher proportion of surgical inpatients (56% vs 22%), however even amongst gastroenterology inpatients, MRE was used at higher rates (39% vs 20%).
Conclusion: MRE has in recent years become the commonest modality used by physicians to assess the small bowel in Crohn’s disease, however surgeons are more likely to still use CT or followthrough techniques.
References:
1.
Panes J, et al, Imaging techniques for assessment of inflammatory bowel disease: Joint ECCO and ESGAR evidence based consensus guidelines, Journal of Crohn's and Colitis (2013),