Value of contrast-enhanced harmonic endoscopic ultrasonography with enhancement pattern for diagnosis of pancreatic cancer: A meta-analysis

Background: Current imaging modalities are limited in their ability to distinguish pancreatic cancer (PC) from non-neoplastic pancreatic lesions. The diagnostic use of contrast-enhanced endoscopic ultrasonography (CE-EUS) has increased, and its utility has been reported. Recently, contrast-enhanced harmonic EUS (CH-EUS) was reported to facilitate imaging of parenchymal perfusion and microvessels in pancreatobiliary diseases, leading to a high diagnostic accuracy for PC. The present meta-analysis aims to investigate the usefulness of CH-EUS with enhancement pattern for PC diagnosis. Methods: A systematic meta-analysis of all potentially relevant articles identified in PubMed, the Cochrane library, and Medline was carried out. Fixed-effects or random-effects models were used to investigate pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio with 95% confidence interval (CI). Results: The study enrolled 887 patients from nine eligible studies. Pooled estimates of sensitivity and specificity were 93% (95% CI, 0.91–0.95) and 80% (95% CI, 0.75–0.85), respectively. Subgroup analyses were carried out on the main results after excluding two outliers. Area under summary receiver operating characteristics curve was 0.97. No publication bias was found using funnel plots. No significant relationship was found between the diagnostic odds ratios and the characteristics of the studies including continent and contrast agent. Conclusions: This meta-analysis showed that CH-EUS with qualitative analysis of enhancement pattern is useful for the diagnosis of PC, and has high sensitivity and accuracy, regardless of the type of contrast agent used. This modality may provide improved diagnostic accuracy for PC in clinical practice.