ABSTRACT
Objective:To explore the microcirculation formation mechanism of contrast-enhanced ultrasonography imaging performance in rabbits with limb muscle crush injury.Methods:Seventy-two New Zealand white rabbits were randomly divided into two groups. A limb muscle crush injury model was created by airing a balloon cuff device with a force of 40 kPa. Contrast-enhanced ultrasonography parameters were detected in the first group.In vivo microcirculation parameters were detected in the second group. Fine blood vessel diameter and blood flow velocity were calculated before extrusion and 0.5 h, 2 h, 6 h, 24 h, and 3 days after decompression.Results:Totally six animals died before the end of the experiment (3 rabbits in ultrasonic imaging and microcirculation detection groups, respectively). Compared with the uninjured muscle, the reperfusion of the injured muscle showed early and high enhancement in contrast-enhanced ultrasonography images. The peak intensity and area under the curve were significantly higher than those of the control subgroup at each time point after decompression(all P<0.05), and reached the peak at 24 h after decompression. The time-intensity curve showed a trend of rapid elevation and gradual drop. In the microcirculation group, compared with the control group, fine artery and vein diameters in the experimental group were wider and the blood flow velocity was slower, especially in the fine veins(all P<0.05). At each time point after decompression, there was a statistical difference between the control subgroup and the control subgroup, and the change reached the peak at 24 h after decompression. The blood flow state showed that the arterioles were dominated by linear flow and linear grain flow at each time point after decompression, and linear grain flow, grain flow and grain pendulum flow were observed in the fine veins. Blood flow stagnation and adhesion of white blood cells and white microthrombus were also observed in the fine veins. Correlation analysis showed that the peak intensity and area under the curve were positively correlated with the inner diameter of arterioles and veins( r=0.84, 0.94; r=0.85, 0.94; all P<0.05), and negatively correlated with the flow velocity of arterioles and veins( r=-0.94, -0.96; r=-0.93, -0.96; all P<0.05). Conclusions:In vivo microcirculation detection can reflect changes in muscle microvascular diameter and blood flow velocity, which have a correlation with quantitative ultrasound imaging parameters.