Ultrasound for diagnosing paediatric intestinal malrotation and midgut volvulus: a retrospective study in a single-centre high-suspicion cohort

Background Intestinal malrotation (IM) is a critical, surgery-requiring condition in children, potentially leading to life-threatening midgut volvulus. Prompt and accurate diagnosis is essential to prevent catastrophic outcomes. While the upper gastrointestinal series (UGI) has been a traditional diagnostic tool, ultrasonography (US) offers a nonradiation-based alternative. Objective To evaluate the diagnostic value of ultrasound (US) in detecting IM and midgut volvulus in a high-clinical-suspicion paediatric cohort. Methods A retrospective analysis was conducted on 143 children with high clinical suspicion of intestinal malrotation at the Children's Hospital between January 2017 and June 2024. All patients received a standardized US assessment, including evaluation of the superior mesenteric artery–superior mesenteric vein (SMA-SMV) relationship, the retroperitoneal position of the third portion of the duodenum (D3), and the presence of the “whirlpool sign.” Using surgical findings or clinical follow-up as the gold standard, the sensitivity, specificity, and accuracy of US for diagnosing intestinal malrotation and of the “whirlpool sign” for diagnosing midgut volvulus were calculated. Results Among the 143 suspected cases, 110 (76.9%) were confirmed to have intestinal malrotation. The sensitivity and specificity of US for diagnosing IM were both 90.9%. Subgroup analysis indicated numerically higher diagnostic sensitivity and accuracy in neonates. Among the 110 patients with surgically confirmed IM, 78 (70.9%) were complicated with midgut volvulus. In this IM-confirmed subgroup, the whirlpool sign demonstrated a sensitivity of 93.6% (73/78) and a specificity of 93.8% (30/32) for identifying midgut volvulus ( P < 0.001). Analysis of the 13 discordant cases (3 false positives, 10 false negatives) revealed that false positives occurred in non-IM conditions such as mesenteric lymphadenitis, while all false negatives were surgically confirmed due to persistent high clinical suspicion. Conclusions In a paediatric cohort with high clinical suspicion, US exhibits high diagnostic efficacy for both IM and midgut volvulus. The whirlpool sign serves as a critical indicator for emergency surgical decision-making. However, a negative US does not completely rule out IM and should be interpreted in conjunction with clinical findings.