Background This study analyzed the diagnostic performance of Doppler ultrasound (DUS) in acute appendicitis (AA) and its ability to discriminate complicated acute appendicitis (CAA) from non-complicated acute appendicitis (NCAA).

Methods This systematic review was prospectively registered in PROSPERO (CRD42025641841). A systematic search was conducted in PubMed, Web of Science, Scopus, and Ovid MEDLINE. Two independent reviewers selected studies and extracted data. Methodological quality was assessed with QUADAS-2. Two random-effects (RE) meta-analyses and three diagnostic test accuracy (DTA) meta-analyses were performed. Publication bias was assessed using Egger’s test and Deeks’ asymmetry test.

Results Twenty-one studies containing 2,774 participants with 1,112 AA patients and 1,145 controls (CG) were included. Peak systolic velocity (PSV) RE meta-analysis (4 articles, 139 AA and 139 CG) showed a significant mean difference [95% CI] of 7.43 [5.37, 9.48] cm/s (p<0.01; I²=59.6%). Resistive index (RI) RE meta-analysis (4 articles, 139 AA and 139 CG) showed a significant mean difference [95% CI] of 0.14 [0.10, 0.19] (p<0.01; I²=52%). Overall Doppler modalities DTA meta-analysis (26 observations) yielded a pooled sensitivity and specificity [95% CI] of 86% [79,91] and 94% [90,96]. The pooled area under the ROC curve (AUROC) was 0.96.

Conclusions DUS is a highly specific tool with excellent diagnostic performance for AA in patients with appendiceal visualization on grayscale US. Evidence concerning its discriminative capacity between CAA and NCAA is limited. Future multicenter studies with adequate design and larger sample sizes must validate these findings.

Registration PROSPERO (CRD42025641841).

The authors have declared no competing interest.

This review did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors, and none of the authors has external funding to declare.

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STATEMENT OF AVAILABILITY OF THE DATA USED DURING THE SYSTEMATIC REVIEW: STATEMENT OF AVAILABILITY OF THE DATA USED DURING THE SYSTEMATIC REVIEW: All data used for the meta-analytical models are available in the accompanying supplementary dataset file.