Systematic review with meta-analysis: Magnetic resonance enterography vs. computed tomography enterography for evaluating disease activity in small bowel Crohn's disease

Background Magnetic resonance enterography (MRE) has been proposed as a non-ionising alternative method to computed tomography enterography (CTE). Some studies have directly compared CTE and MRE in patients with small bowel Crohn's disease (CD) with variable results. Aim To compare the overall diagnostic accuracy in assessing the activity of small bowel and complications. Methods MEDLINE, EMBASE and Cochrane databases were searched for studies on the accuracy of MRE and CTE, as compared with a pre-defined reference standard. Pooled sensitivity, specificity, the weighted area under the curve (AUC), incremental yield (IY) and other diagnostic indices were evaluated. Results A total of 290 CD patients from six different studies were analysed. The pooled sensitivity and specificity for MRE in detecting active small bowel CD was 87.9% [95% confidence interval (CI), 81.8-92.5] and 81.2% (95% CI: 71.9-88.4) respectively. The AUC under the summary receiver-operating characteristic (sROC) of MRE was 0.905 (SEM 0.03, standard error of the mean). Likewise, the pooled sensitivity and specificity of CTE in detecting active small bowel CD was 85.8% (95% CI: 79.2-90.9) and 83.6% (95% CI: 75.3-90.1) with the AUC of 0.898. The AUC of MRE in detecting fistula, stenosis and abscess was 0.936, 0.931 and 0.996, respectively, compared to 0.963, 0.616 and 0.899 of CTE. No statistically significant IY for MRE vs. CTE was found (fixed model, P > 0.05). Conclusions Magnetic resonance enterography has a diagnostic effectiveness comparable to computed tomography enterography, thus may serve as a radiation-free alternative for evaluation of patients with Crohn's disease.