Background: Crohn's disease (CD) involves the small bowel (SB) in at least 70% of those affected. Capsule endoscopy (CE), magnetic resonance enterography (MRE) and SB intestinal contrast ultrasound (SICUS) are the modalities of choice for SB evaluation. In CD, proximal SB disease is associated with worse long-term outcomes. This study aimed to compare the diagnostic yield (DY) of CE, MRE and SICUS in detection and monitoring of SB CD by performing a systematic review and meta-analysis of the available literature.
Methods: MEDLINE and EMBASE searches were performed using the search terms “capsule endoscopy”, “ultrasound”, “magnetic resonance enterography” and “Crohn's disease”. We retrieved prospective trials comparing the accuracy of CE, MRE and SICUS for detection of active SB disease in patients with suspected and established CD. Only prospective studies comparing CE with at least one additional diagnostic modality were included. Odds ratios (ORs) for DY with 95% confidence intervals (CIs) were calculated. Where data were available, DY was also analyzed separately for proximal and distal SB.
Results: A total of 138 studies were retrieved by the literature search; 12 studies were eligible for analysis. The DYs of CE, MRE and SICUS were similar for the overall population. The OR for DY of CE vs MRE was 0.56 (95% CI 0.28–1.13, p=0.1; I2=72%; 9 studies, 376 patients). The OR for CE vs SICUS was 0.85 (95% CI 0.69–1.38; p=0.23; I2=15%l 4 studies, 122 patients) (Fig. 1).
The DY for distal SB disease was similar to the overall analysis, OR 1.58 (95% CI 0.56–4.46; p=0.41; I2=71%; 6 studies, 220 patients). Segmental analysis was not possible for SICUS due to a low number of studies.
DY was similar in suspected and established CD. Comparing CE to MRE, CE had superior DY for proximal SB disease with OR 2.62 (95% CI 1.10–6.53; p=0.03; I2=71%; 6 studies, 220 patients) (Fig. 2).
Conclusions: CE, MRE and SICUS have similar DY for detection of SB CD in both suspected and established CD. CE was superior to MRE for detection of proximal SB involvement; this may have important practical implications due to the prognostic impact of SB disease.