To analyze the quantitative parameters of hepatic microperfusion by contrast-enhanced ultrasound in rabbits with brain death, in order to explore a new method for evaluating the donor liver of individuals with brain death.

Rabbits with brain death (n=15) were prepared by surgery and maintained for 8 hours, and rabbits undergoing sham operation were used as controls (n=5). Contrast-enhanced ultrasonography and quantitative analysis of microblood flow were performed in the two groups at 0 h, 4 h, and 8 h after modeling. The quantitative parameters included area under the curve (AUC), peak intensity (PI), peak time (Tp), and average transit time (MTT). The t-test was used to compare the differences of liver contrast-enhanced ultrasound quantitative parameters AUC, PI, Tp, and MTT between the two groups at different time points. Liver function and pathology were evaluated at the same time.

Under the condition of brain death, the AUC values of 13 rabbits (13/15, 86.7%) showed a gradually downward trend, and the PI values of 15 rabbits (15/15, 100%) showed a gradually downward trend. At 0 h after modeling, the PI value of the brain death group was significantly higher than that of the control group [(66.1±9.1)% vs (54.9±7.3)%, t=-11.276, P=0.032], and at 8 h, the PI value of the brain death group was significantly lower than that of the control group [(44.9±10.3)% vs (68.5±2.9)%, t=-10.395, P=0.001]; at 4 h, there was no significant difference in the PI value between the two groups (P＞0.05). Eight hours after modeling, the AUC value of the brain death group was significantly lower than that of the control group [(2591.7 ±732.7)%s vs (4520.0 ±182.8)%s, t=-18.762, P＜0.001], but there was no significant difference at 0 h and 4 h (P＞0.05). At 0 h, 4 h, and 8 h after modeling, there was no significant difference in the Tp scores and MTT values between the two groups (P＞0.05).

The amount of hepatic microperfusion decreases in rabbits with brain death, and contrast-enhanced ultrasound can be used as an effective method to evaluate the donor liver of individuals with brain death.