AJR (@ajrradiology.bsky.social)

Diagnostic Performance of Individual CT Signs for Identifying Ischemia and Necrosis in Small Bowel Obstruction: A Systematic Review and Meta-Analysis | AJR BACKGROUND. CT has established strong performance in diagnosing small bowel obstruction (SBO). Uncertainty remains regarding the performance of individual CT signs in diagnosing associated ischemia or necrosis. OBJECTIVE. To conduct a systematic review and meta-analysis of the diagnostic performance of individual CT signs for detecting ischemia and necrosis in patients with SBO. EVIDENCE ACQUISITION. The MEDLINE, Embase, and Web of Science database were searched through April 2024 for original research studies evaluating the diagnostic performance of individual CT signs in detecting surgically confirmed bowel ischemia and/or pathologically confirmed bowel necrosis in patients with SBO; uneventful clinical follow-up was permitted for determining absence of these outcomes. Bivariate random-effects meta-analyses were performed for CT signs reported in ≥3 studies with ≥100 total patients. Signs were considered predictive of an outcome if exhibiting pooled specificity exceeding 85% and diagnostic OR exceeding 10. Signs were considered to reliably exclude an outcome if having a negative likelihood ratio (NLR) less than 0.10. EVIDENCE SYNTHESIS. The analysis included 19 studies reporting 2453 patients with 2489 SBO episodes (600/2029 [30%] with ischemia, 241/651 [37%] with necrosis). Of 14 signs evaluated for ischemia, four were predictive: increased unenhanced bowel wall attenuation (specificity 98%, DOR 30.50, sensitivity 36%), reduced bowel wall enhancement (specificity 92%, DOR 15.80, sensitivity 55%), diffuse mesenteric haziness (specificity 89%, DOR 22.30, sensitivity 72%), and closed-loop configuration (specificity 85%, DOR 19.60, sensitivity 75%). Of 11 signs evaluated for necrosis, one was predictive: increased unenhanced bowel wall attenuation (specificity 92%, DOR 18.0, sensitivity 55%). No sign had sufficiently low NLR to reliably exclude either outcome (lowest NLR of 0.30 for closed-loop configuration for both outcomes). CONCLUSION. In patients with SBO, four CT signs (increased unenhanced bowel wall attenuation, reduced bowel wall enhancement, diffuse mesenteric haziness, and closed-loop configuration) were predictive of ischemia; one of these signs, increased bowel wall attenuation, was also predictive of necrosis. No sign could reliably exclude either outcome. CLINICAL IMPACT. The identified signs could be prioritized when interpreting CT examinations in patients with SBO, to help guide surgical decision-making. Additionally, noncontrast acquisitions may warrant inclusion in routine CT protocols for SBO evaluation. https://www.auntminnie.com/clinical-news/ct/article/15823650/4-ct-signs-help-predict-ischemia-in-small-bowel-obstruction