Corresponding author: Mansoureh Fatahi, (Shahid Beheshti University of — fattahi.110203@yahoo.com
Submitted: 10 Sep 2025 · Accepted: 13 Jan 2026
Acute appendicitis is the most common surgical emergency in children. While up to 85% of pediatric appendicitis cases are uncomplicated, the rate of complicated appendicitis can be significant, ranging from approximately 30% overall to as high as 50–75% in certain cohorts [1]. Ultrasound (US) is a first-line imaging modality, yet its diagnostic performance in accurately identifying these complications remains uncertain [2].
Following PRISMA [3], we searched PubMed, Embase, Web of Science, and Scopus from inception. Risk of bias was assessed with QUADAS-2. Bivariate random effect model pooled sensitivity and specificity; heterogeneity was summarized using I² and Q; small-study effects were evaluated using Deeks’ test. Clinical utility was illustrated using a Fagan nomogram, and overall accuracy was assessed using a summary receiver-operating characteristic (SROC) curve.
Twenty-one studies met the inclusion criteria. Nearly all procedures were conducted by specialists or residents in radiology. The age range for the pediatric population was between 0 to 18 years old. Pooled US sensitivity for identifying complicated appendicitis was 0.52 (95% CI 0.41–0.62), and specificity was 0.90 (0.84–0.94) (Figure 1). The area under the curve was 0.80 (0.76–0.83) (Figure 2), and the summary operating point mirrored the pooled estimates. Deeks’ test suggested no significant asymmetry (p=0.08). Assuming a pre-test probability of 25%, a positive US result (LR+ = 5) increased the post-test probability to ~64%, whereas a negative result (LR–=0.54) reduced it to ~15%.
In pediatric appendicitis, US demonstrates high specificity but moderate sensitivity for discriminating complicated from simple disease. A positive scan can “rule in” complication and support expedited, targeted management; a negative scan cannot exclude complication and should be interpreted alongside clinical findings, laboratory data, and, when indicated, adjunct imaging. Future studies should standardize sonographic criteria and report per-feature performance to refine thresholds and reduce heterogeneity.
1. Shahid Beheshti University of Medical Sciences, Tehran, Iran
2. School of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran
All authors contributed equally and validated the final version of record.
The Authors declare that there is no conflict of interest.
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
No registration applicable.
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Ethical approval for this study was not required.