Diagnostic Performance of Contrast-Enhanced Ultrasound (CEUS) and Contrast-Enhanced Endoscopic Ultrasound (ECEUS) for the Differentiation of Pancreatic Lesions: A Systematic Review and Meta-Analysis

Purpose: To evaluate CEUS for the diagnosis of pancreatic diseases and its application in the clinical routine with a focus on the value of CEUS in ductal pancreatic carcinoma and its use for the differentiation of neoplastic and non-neoplastic lesions. Materials and Methods: All prospective and retrospective studies published in any language by March 6, 2014 were included based on the following criteria: use of contrast-enhanced ultrasound (CEUS) and contrast-enhanced endoscopic ultrasound (ECEUS) as the imaging methods, use of histology as the reference method and availability of a complete translation. Two authors analyzed the titles and abstracts of the search results to identify all relevant publications. Two independent readers then analyzed the full articles to identify those meeting the inclusion criteria. Details regarding study design, patient characteristics, interventions, and results were then independently extracted by two radiologists and one reviewer with methodological expertise. Sensitivity, specificity and diagnostic odds ratio (DOR) were used to obtain overall estimates. Results: 1293 articles were initially identified. 27 studies met the inclusion criteria. CEUS was the index test in 23 studies while ECEUS was the index test in 4 studies. The primary study objective was met by 20 studies with respect to ductal adenocarcinoma. CEUS sensitivity was evaluated in all studies. The pooled estimate of CEUS sensitivity for the diagnosis of ductal adenocarcinoma was 0.89 (95 % CI, 0.85 - 0.92). 15 out of 20 studies examined CEUS specificity. The average specificity was 0.84 (95 % CI, 0.77 - 0.89). The pooled estimate for DOR was 61.12 (95 % CI, 34.81 - 107.32). With regard to the secondary study objective, the pooled sensitivity and specificity were 0.95 (95 % CI, 0.93 - 0.96) from 14 studies and 0.72 (95 % CI, 0.58 - 0.83) from 13 studies, respectively. The pooled DOR was 57.63 (95 % CI, 33.62 - 98.78). Conclusion: The sensitivity, specificity, and DOR results show the high value of CEUS for the characterization and differentiation of ductal adenocarinomas from other pancreatic diseases and for cystic pancreatic lesions. For this reason and due to their non-invasive nature, CEUS and ECEUS should be used as the first methods for characterizing neoplastic pancreatic lesions, especially since these are often incidental findings. The methods improve the quality of ultrasound diagnostics and result in faster diagnosis and better disease management.