Diagnostic Performance of Doppler Ultrasound for Acute Appendicitis: A Systematic Review and Diagnostic Test Accuracy Meta-Analysis

This systematic review and diagnostic test accuracy meta-analysis evaluated the performance of Doppler ultrasound (DUS) for diagnosing acute appendicitis (AA) and its ability to distinguish complicated (CAA) from non-complicated acute appendicitis (NCAA). The review was registered in PROSPERO (CRD42025641841), and a comprehensive search was conducted across PubMed, Web of Science, Scopus, and Ovid. Twenty-one studies were included. Study quality was assessed using the QUADAS-2 tool. Continuous quantitative parameters were synthesized using random-effects models (REML) while diagnostic performance data were analyzed through hierarchical models. For Spectral Doppler parameters, PSV showed a pooled sensitivity of 94% [89–97] and specificity of 87% [71–95], while RI showed a pooled sensitivity of 81% [68–89] and specificity of 88% [73–95]. Color Doppler (CD) achieved a pooled sensitivity of 82% [70–90], specificity of 97% [92–99], and AUC of 0.97 [0.95–0.98], with potential evidence of small-study effects (Deeks’ test p = 0.08). Evidence for discriminating CAA from NCAA was limited and heterogeneous. Although DUS—particularly CD and SD—shows encouraging diagnostic potential for AA, the presence of moderate heterogeneity, retrospective study designs, potential small-study effects (CD), and significant spectrum bias suggests that its performance is probably overestimated. Nevertheless, the consistently high accuracy estimates across multiple modalities, together with its radiation-free nature and broad availability, highlight DUS as a highly attractive complementary imaging option. Therefore, while conclusions must be interpreted cautiously until validated by large, prospective, multicenter studies with standardized thresholds and imaging protocols, our findings support DUS as a promising diagnostic tool for AA assessment, particularly in pediatric and radiation-sensitive populations, provided that the cecal appendix is adequately visualized.