Abstract: Objective To investigate the value of contrast-enhanced ultrasound combined with ultrasound elastography in predicting microvascular invasion (MVI) of hepatocellular carcinoma (HCC). Methods The data of 75 patients with HCC admitted from May 2019 to March 2022 were retrospectively analyzed. According to the postoperative pathological examination, the patients were divided into a non-MVI group (n=28) and a MVI group (n=47). All patients were given ultrasound elastography and contrast-enhanced ultrasound before surgery. The quantitative parameters of ultrasound elastography and contrast-enhanced ultrasound were compared between the two groups. The factors affecting the occurrence of MVI in HCC, and the value of contrast ultrasound, elastography and their combination in predicting MVI in HCC were analyzed. Results The clearance time of MVI group was shorter than that of non-MVI group [(60.57±19.45) s vs (83.23±25.74) s, P<0.05]. There was no significant difference between the onset time and peak time between these two groups of patients (P>0.05). Although there was no significant difference in the hardness at 2 cm of tumor edge (S2) between two groups (P>0.05), the hardness at 1 cm of tumor margin (S1) in MVI group and S1/S2 index were higher than those in non-MVI group [(11.89±4.22) kPa vs (10.06±2.15) kPa, (13.04±2.76) vs (010.28±2.18), respectively, (P<0.05)]. The average of tumor length diameter, and the level of aspartate aminotransferase, the proportions of patients with multi-focal tumors and alpha-fetoprotein (AFP) > 400 μg/L in MVI group were higher than those in non-MVI group (P<0.05), whereas the level of albumin and platelet counts in MVI group were lower than those in non-MVI group (P<0.05). The increased tumor length (OR: 2.843, 95%CI: 1.250-6.468), with multi-focal tumors (OR: 3.251, 95%CI: 1.429-7.394), AFP>400 μg/L (OR: 3.999, 95%CI: 1.758-9.097), shortened clearance time (OR:3.504, 95%CI: 1.540-7.972) and increased S1/S2index (OR: 4.272, 95%CI: 1.878-9.717) were the influential factors associated with MVI development of HCC (P<0.05). By receiver operating characteristic curve (ROC) analysis, it was shown that the sensitivity of clearance time, S1/S2index value and their combined prediction of MVI in HCC were 82.98%, 85.11% and 85.11%,, and the specificity was 82.14%, 85.71% and 96.43%, respectively. The area under the curve (AUC) values were 0.781, 0.843 and 0.927 (P<0.05), respectively, and the AUC values of the two combined prediction were higher (P<0.05). Conclusion The clearance time of quantitative parameters of CEUS combined with S1/S2 index value of quantitative parameters of ultrasound elastic imaging has higher value in predicting MVI of HCC.

Key words: Contrast-enhanced ultrasound, Ultrasonic elastic imaging, Hepatocellular carcinoma, Microvascular invasion, Predictive value