Improved sensitivity and positive predictive value of contrast-enhanced intraoperative ultrasound in colorectal cancer liver metastasis: a systematic review and meta-analysis.

Background: Surgery is an effective treatment for improving the survival rate of patients with colorectal cancer liver metastases (CRLM). However, accurately determining the resection margin of liver lesions during surgery remains challenging. Therefore, this study aimed to evaluate the sensitivity and predictive value of intraoperative contrast-enhanced ultrasound (CE-IOUS) in CRLM patients undergoing surgery. Methods: We performed a literature search of the PubMed, Cochrane Central Register of Controlled Trials, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang, and Weipu databases using the following search terms: metastatic liver cancer, colorectal cancer, sensitivity, contrast-enhanced intraoperative ultrasound, CE-IOUS, colorectal liver metastases, and CRLM. The search period was set from the date of establishment of the database to September 2021. Quality assessment of diagnostic accuracy studies 2 (QUADAS-2) recommended by the Cochrane Collaboration was used to assess the methodological quality of the included studies, and network meta-analysis was performed using Stata 15.0 software. Results: A total of 10 articles met the inclusion criteria. The meta-analysis results showed that the overall sensitivity and specificity of CE-IOUS were 0.96 [95% confidence interval (CI), 0.95-0.97] and 0.75 (95% CI, 0.70-0.80), respectively. The overall sensitivity and specificity of IOUS were 0.84 (95% CI, 0.82-0.86) and 0.82 (95% CI, 0.77-0.87), respectively. The area under the summary receiving operating characteristic (SROC) curves (AUCs) of CE-IOUS and IOUS were 0.9753 and 0.8590, respectively. The odds ratio (OR) and 95% CI of CE-IOUS changed the surgical margin were 0.205 and 0.071-0.465, P=0.000, the difference was statistically significant. Discussion: Based on the results of this meta-analysis, CE-IOUS improved the sensitivity and predictive value of CRLM detection compared with IOUS, and is more suitable for intraoperative planning of surgical margins. At present, it is the most sensitive imaging method available, and is recommended for use during liver resection to provide doctors with more reliable information during surgery.