Abstract Objective ：To quantitatively evaluate the early efficacy of antivascular targeted therapy for colorectal cancer liver metastases by dynamic contrast-enhanced ultrasound . Methods :A total of 54 patients with colorectal cancer liver metastases treated in our hospital from January 2018 to May 2021 were selected as the research objects.  Among them

25 patients were treated with bevacizumab combined with FOLFOX/FOLFIRI regimen as the study group

and 29 patients were treated with FOLFOX/FOLFIRI regimen only as the control group. The quantitative parameters of all patients were obtained by dynamic contrast-enhanced ultrasound (CEUS)

and the differences before and after treatment were compared. The ROI area of the target lesions was delimited

and the time-intensity curve was drawn to understand the critical value of the predictive efficacy index. Results : In the control group

5 patients received FOLFOX4 regimen

9 patients received FOLFOX6 regimen

and 15 patients received FOLFIRI regimen.  23 cases were ineffective and 6 cases were effective.  In the study group

7 patients received bevacizumab +FOLFOX6 regimen

and 18 patients received bevacizumab +FOLFIRI regimen.  7 cases were ineffective and 18 cases were effective. There was no significant difference in tumor size between the two groups before and after treatment.  The quantitative parameters of CEUS such as PI

Pw and AUC in the study group were statistically different before and after treatment (P<0.05)

and the AUC in the control group was statistically different before and after treatment (P<0.05)

but there was no significant difference in the other parameters (P>0.05).The quantitative parameters of contrast-enhanced ultrasound were further compared between the two groups according to whether the treatment was effective or not. It was found that the PI and Pw of the effective group after treatment were lower than those before treatment

showing a downward trend

while those of the ineffective group were higher than those before treatment.  The PI of the effective group before and after treatment was lower than that of the ineffective group before and after treatment

but there was no statistical difference (P> 0.05). The PI difference of the effective group before and after treatment was higher than that of the ineffective group

and there was statistical difference (t=5.135

P=0.002<0.05). The Pw of the effective group before and after treatment was lower than that of the ineffective group before and after treatment

respectively.  However

the difference of Pw before and after treatment in effective group was significantly higher than that in ineffective group

and the difference was statistically significant (t=4.557

P=0.01< 0.05). There was no significant difference in PI and Pw between the effective group and the ineffective group before and after treatment in the control group (P>0.05).Conclusion :When the tumor size does not change significantly in the early stage of treatment

dynamic contrast-enhanced ultrasound can predict the early efficacy of anti-angiogenesis targeted therapy for colon cancer liver metastases through tumor blood perfusion

and has better clinical efficacy for patients with high Pw level and high blood flow velocity and volume.