Intestinal Ultrasonography for Predicting Postoperative Endoscopic Recurrence and Assessing Risk of Intestinal...

Background/Objectives: Postoperative endoscopic recurrence is common after intestinal resection for Crohn's disease (CD), making surveillance essential. We performed a systematic review and meta-analysis evaluating the diagnostic performance of intestinal ultrasonography (IUS) for postoperative endoscopic recurrence and the prognostic association of IUS findings with surgical outcomes in the overall CD population. Methods: MEDLINE (PubMed) and Embase were searched from inception through 1 July 2026, for prospective studies evaluating postoperative IUS in CD. Diagnostic accuracy was analyzed using random-effects bivariate meta-analysis to estimate pooled sensitivity, specificity, likelihood ratios, summary receiver operating characteristic (SROC) curves, and diagnostic odds ratios (DORs). Results: Twenty-six prospective studies were included, comprising 797 patients evaluated for postoperative endoscopic recurrence and 1060 patients evaluated for associations between IUS findings and subsequent intestinal surgery. A bowel-wall thickness (BWT) threshold of >3.0 mm demonstrated high diagnostic accuracy for detecting any postoperative endoscopic recurrence (Rutgeerts ≥ i1), with pooled sensitivity of 85%, specificity of 83%, DOR of 30.8, and SROC AUC of 0.91, positive likelihood ratio of 5.3, and negative likelihood ratio of 0.19. For postoperative endoscopic recurrence (Rutgeerts ≥ i2), pooled sensitivity and specificity were lower at 79% and 67%, respectively (DOR 8.3; SROC AUC 0.76). A BWT threshold of >5.0 mm identified severe endoscopic recurrence (Rutgeerts i3-i4) with sensitivity of 79% and specificity of 81%, while a threshold of ≥7.0 mm was associated with increased risk of intestinal resections in the overall CD population. Conclusions: IUS demonstrated high diagnostic performance for postoperative endoscopic recurrence of CD with balanced sensitivity and specificity, and favourable likelihood ratios, although performance varied according to the definition and severity of recurrence. Evidence regarding diagnostic accuracy for modified Rutgeerts scores remains limited. Overall, these findings support IUS as a complementary modality to ileocolonoscopy, enabling repeated postoperative monitoring and risk stratification for endoscopic recurrence and surgery.