Comparative analysis of elastosonography and 18 F-FDG PET/CT in differentiating benign and malignant salivary gland tumors: a systematic review and meta-analysis

Purpose We conducted a systematic review and meta-analysis to assess and compare the diagnostic performance of elastosonography and 18 F-FDG PET/CT in differentiating between benign and malignant salivary gland tumors. Methods Using PICOS criteria, experimental and observational research evaluating elastosonography or 18 F-FDG PET/CT for differentiating benign and malignant salivary gland tumors were included. A systematic search was conducted across PubMed, Embase, Web of Science, Scopus, Cochrane Library, and CINAHL, initially in July 2024 and updated in February 2025. A manual search for relevant gray literature was also performed. Data extraction and risk of bias assessment using QUADAS-2 were conducted independently by reviewers. Results A total of 26 studies with 1609 patients were included in the analysis. The pooled sensitivity of elastosonography and 18 F-FDG PET/CT in the differential diagnosis of benign and malignant salivary gland tumors were 0.75 (95% CI 0.65-0.84) and 0.84 (95% CI 0.78-0.90), specificity was 0.79 (95% CI 0.69-0.87) and 0.85 (95% CI 0.69-0.96), respectively. The area under the curve (AUC) for elastosonography and 18 F-FDG PET/CT were 0.83 and 0.92 and there is a statistical difference between the two imaging modalities (Z = 2.77, P < 0.01). Fagan nomogram indicated that when the pre-test probability was set at 20%, the post-test probability for elastosonography and 18 F-FDG PET/CT could increase to 50% and 65%. Conclusion In differentiating between benign and malignant salivary gland tumors, 18 F-FDG PET/CT exhibits a superior AUC compared to elastosonography, suggesting that, despite its current limited use in the initial workup of salivary gland tumors, there may be a strong argument for its increased adoption in clinical practice. Nevertheless, it is crucial to note that the findings of this meta-analysis rely on studies with limited sample sizes. More extensive prospective studies are warranted to validate these results further.