Diagnosis of parotid gland tumours with Contrast-Enhanced Ultrasound: a systematic review and meta-analysis

Aim: Contrast-enhanced ultrasound (CEUS) appears to be a promising application for the diagnosis of parotid gland tumours. We aimed to systematically review and meta-analyse the ability of CEUS in distinguishing benign from malignant parotid gland tumours.Material and methods: PubMed was searched for relevant studies. Data on area under time intensity curve (AUC) in arbitrary unit (AU), and mean transit time (MTT) in seconds (sec) were analysed using the Cochrane Review Manager Software.Results: Nine studies met the eligibility criteria comprising a total number of 498 parotid gland tumours (benign, number (n)=423; malignant, n=75). Descriptive evaluation of parotid gland tumours following CEUS administration showed overlap characteristics in benign and malignancies. Two publications assessed AUC and MTT in 72 and 60 parotid gland tumours, respectively. AUC was significantly lower in benign compared to malignant tumours following contrast administration (AUC, mean difference (MD) -266.77 AU, 95% confidence intervals (CI) -433.22, -100.33, p=0.002). No significant different in MTT between benign and malignant tumours (p=0.12). Heterogeneity was statistically significant in AUC (p=0.04) and MTT (p<0.00001).Conclusion: Descriptive evaluation of parotid gland tumours showed overlap CEUS characteristics. Perfusion related CEUS parameters analysis is promising in differentiating benign parotid tumours from malignancies.