Published online Aug 21, 2019. doi: 10.3748/wjg.v25.i31.4555
Peer-review started: March 28, 2019
First decision: June 6, 2019
Revised: June 25, 2019
Accepted: July 19, 2019
Article in press: July 19, 2019
Published online: August 21, 2019
Processing time: 142 Days and 11.4 Hours
Cross-sectional imaging evaluation of the small bowel is recommended in Crohn’s Disease (CD) to determine the grade of disease activity and the extent of bowel involvement. Magnetic resonance enterography/enteroclysis (MRE) is often preferred over other cross-sectional imaging modalities due to its ability to demonstrate transmural involvement or extraenteric complications and the lack of radiation exposure.
Layered pattern (LP) of bowel walls’ contrast enhancement is commonly observed at MRE in patients with CD. Nevertheless, it remains uncertain whether LP has to be considered as a sign of active inflammation or rather correlates with chronic changes and the presence of coexisting fibrosis. A better characterization of the clinical significance of LP may further expand the role of MRE, helping clinicians to choose the best treatment option and to monitor response to therapies over the course of the disease.
We performed a systematic review and meta-analysis aiming to estimate the diagnostic performance of LP of bowel walls’ enhancement at MRE in detecting inflammatory activity in CD.
Electronic search was performed to identify studies that investigated the diagnostic accuracy of LP for the recognition of active inflammation in patients with known or suspected CD using ileocolonoscopy with biopsy or surgical specimens’ histopathological analysis as reference standard. Quality Assessment for Diagnostic Accuracy Studies 2 (QUADAS-2) was employed to assess methodological quality of the included studies. Pooled data on diagnostic accuracy were estimated by means of bivariate random-effect model analysis.
After full-text review, five studies met the inclusion criteria for quantitative analysis. Cumulative data on LP diagnostic accuracy demonstrated by meta-analysis were as follows: pooled sensitivity, 49.3% (95%CI: 41.0%-57.8%); pooled specificity, 89.1% (95%CI: 81.3%-94.4%); pooled PLR, 3.3 (95%CI: 1.9-5.7); pooled NLR, 0.6 (95%CI: 0.5-0.9); and SDOR, 6.8 (95%CI: 2.6-17.6). Summary ROC curve returned an area under the curve (AUC) of 0.82 (SE 0.06). High risk of bias and applicability concerns were raised up in relation to patient selection in one of the included studies.
LP of bowel walls’ enhancement at MRE yields high specificity for active inflammation in patients with CD.
Our findings may further refine the role of MRE in characterizing inflammatory activity in CD, providing relevant information to ensure proper therapeutic management. Future prospective studies adopting a prespecified definition of LP are advisable to further support our findings.