Differentiation between hepatocellular carcinoma and intrahepatic cholangiocarcinoma using contrast-enhanced ultrasound: A systematic review and meta-analysis

AIM: To explore the diagnostic ability of contrast-enhanced ultrasound (CEUS) in distinguishing intrahepatic cholangiocarcinoma (ICC) from hepatocellular carcinoma (HCC). MATERIALS AND METHODS: PubMed, EMBASE, Cochrane Library, and Web of Science were systematically searched for studies reporting the diagnostic accuracy of CEUS in differentiating ICC from HCC. The diagnostic ability of CEUS was assessed based on the pooled sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (PLR), negative likelihood ratio (NLR) and area under the curve (AUC) with 95% confidence intervals (CIs). The methodologic quality was assessed by the QUADAS-2 tool. Subgroup analyses, meta-regression and investigation of publication bias were performed to identify the source of heterogeneity. RESULTS: A total of eight studies were included, consisting of 1,116 patients with HCC and 529 with ICC. The general diagnostic performance of CEUS in distinguishing ICC and HCC were as follows: pooled sensitivity, 0.92 (95% CI: 0.84–0.96); pooled specificity, 0.87 (95% CI: 0.79–0.92); pooled PLR, 7.1 (95% CI: 4.1–12.0); pooled NLR, 0.09 (95% CI: 0.05–0.19); pooled DOR, 76 (95% CI: 26–220) and AUC, 0.95 (95% CI: 0.93–0.97). Different liver background may be a potential factor that influenced the diagnostic accuracy of CEUS according to the subgroup analysis, with the pooled DOR of 89.67 in the mixed liver background group and 46.87 in the cirrhosis group, respectively. Six informative CEUS features that may help differentiate HCC from ICC were extracted. The three CEUS features favoring HCC were arterial phase hyperenhancement (APHE), mild washout and late washout (>60s); the three CEUS favoring ICC were arterial rim enhancement, marked washout and early washout (<60s). No potential publication bias was observed. CONCLUSION: CEUS showed great diagnostic ability in differentiating ICC from HCC, which may be promising for noninvasive evaluation of these diseases.