Contrast-enhanced ultrasound for the characterization of portal vein thrombosis vs tumor-in-vein in HCC patients: a systematic review and meta-analysis.

Objectives: Portal vein thrombosis (PVT) is a common complication of liver cirrhosis. However, differentiation of thrombosis and tumor-in-vein (TIV) may be challenging. Contrast-enhanced ultrasound (CEUS) is an excellent method for detection of vascularization and could help in the distinction. We performed a systematic review and meta-analysis for evaluating the diagnostic value of CEUS in differentiating between PVT and TIV in hepatocellular carcinoma (HCC) patients.

Methods: PubMed, Embase, Cochrane Library, and Web of Science were searched up to the 5th of May 2019. The study quality was assessed by QUADAS-2 tool. Pooled sensitivity and specificity were calculated by the bivariate random effect model and hierarchical summary receiver-operating characteristic (SROC) curve was plotted.

Results: Seven studies including 425 participants were analyzed after screening 986 articles searched from databases. The pooled sensitivity and specificity of CEUS in diagnosing TIV were 0.94 (95%CI, 0.89-0.97) and 0.99 (95%CI, 0.80-1.00), respectively. The area under the curve (AUC) of SROC curve was 0.97 (95%CI, 0.95-0.98). The pooled sensitivity and AUC were consistent across all the subgroups of different subject numbers, country, study design, CEUS contrast agents, and diagnostic criteria.

Conclusions: CEUS is highly efficient in differentiating TIV from PVT and is an alternative or a substitute for CT and/or MRI.

Trial Registration: PROSPERO registration number: CRD42019138847 KEY POINTS: • Characterization of portal vein thrombosis (PVT) vs tumor-in-vein (TIV) is critical for HCC staging. • CEUS has an excellent safety profile, provides a real-time analysis without any loss in accuracy compared with CT and MRI. • This meta-analysis demonstrates that contrast-enhanced ultrasound (CEUS) is a suitable method for the detection of PVT and distinction with TIV.