CT IMAGING PREDICTORS OF PATHOLOGIC PNEUMATOSIS INTESTINALIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

Introduction: Pneumatosis intestinalis (PI) is a computed tomography (CT) sign rather than a diagnosis, and it spans a spectrum from incidental benign gas to transmural bowel ischaemia and necrosis. Inappropriate interpretation leads either to delayed surgery for necrotic bowel or to non-therapeutic laparotomy. This review aimed to identify and quantify the abdominal CT findings that discriminate pathologic (life-threatening) PI from benign PI.

Methods: The study strictly adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines. Randomized controlled trials, prospective and retrospective cohort, case–control and cross-sectional studies of patients with CT-detected PI that compared CT findings between pathologic PI (transmural ischaemia/necrosis at surgery, pathology or autopsy, PI-related death, or study-defined life-threatening PI) and benign PI were eligible. Risk of bias was assessed with the Quality In Prognosis Studies (QUIPS) tool and the Newcastle–Ottawa Scale. Odds ratios (OR) were pooled with DerSimonian–Laird random-effects models, with Hartung–Knapp–Sidik–Jonkman, subgroup, leave-one-out and cumulative analyses; small-study effects were examined with funnel plots, Egger and Begg tests and Doi plots. Certainty was rated with GRADE for prognostic factors.

Results: Twenty-five cohort studies (4,392 patients) were included; no randomized trials were identified. Twelve studies contributed to meta-analysis. Decreased or absent bowel wall enhancement showed the strongest association with pathologic PI (OR 17.51, 95% CI 1.71–179.17; k = 3; I² = 79%), followed by mesenteric arterial/venous thrombosis or occlusion (OR 5.26, 95% CI 2.07–13.36; k = 3; I² = 0%), hepatic portal venous gas (OR 3.48, 95% CI 2.08–5.80; k = 7), any portal/portomesenteric venous gas (PMVG) (OR 3.32, 95% CI 2.23–4.96; k = 8; 1480 patients; I² = 48%), mesenteric venous gas (OR 2.84, 95% CI 1.71–4.72), ascites (OR 2.77, 95% CI 2.09–3.67; I² = 0%) and small-bowel location (OR 1.88, 95% CI 1.41–2.52). Isolated foci of PI were associated with benign PI (OR 0.41, 95% CI 0.27–0.62). Pneumoperitoneum (OR 1.02, 95% CI 0.64–1.63), bowel wall thickening (OR 1.25, 95% CI 0.93–1.68), colonic location (OR 0.91, 95% CI 0.70–1.17), bowel dilatation (OR 2.05, 95% CI 0.69–6.09) and multisegment extent (OR 1.68, 95% CI 0.94–3.00) were not significantly associated. PMVG had high specificity (80%) but low sensitivity (45%). Mesenteric fat stranding could not be pooled; it was significantly associated with pathologic PI in 3 of 8 reporting studies. Results were robust in sensitivity analyses, and no small-study effect was detected for PMVG (Egger p = 0.91).

Discussion: CT findings that reflect compromised mural perfusion (hypoenhancement, vascular occlusion) carry the greatest weight, whereas gas-related findings (PMVG) are specific but insensitive, and pneumoperitoneum alone is not a marker of pathologic PI. Certainty was moderate for PMVG, ascites and small-bowel location and low for hypoenhancement and thrombosis because of heterogeneity and imprecision.

Conclusion: A structured CT appraisal of PI should prioritise bowel wall enhancement and mesenteric vascular patency, followed by PMVG, ascites and small-bowel involvement, and must always be integrated with clinical and laboratory red flags. Prospective, protocolised multicentre studies with standardized CT definitions and validated multivariable models are needed.