不同频率和强度超声波溶栓效果的体外实验

Sonothrombolysis at different frequencies and intensities: an experimental study in vitro

目的探讨体外实验条件下超声频率和强度对其溶栓效率的影响。方法取健康人全血标本56份,37℃恒温水浴孵育2h后形成体外血栓。样本被分为5个辐照组和1个对照组。辐照组分别以0.7W/cm2,0.5MHz;0.7W/cm2,1MHz;0.7W/cm2,2MHz;1.4W/cm2,2MHz和1.8W/cm2,2MHz的脉冲式超声波照射10min;对照组无超声处理。计算血栓溶栓率,比较各相同声强不同频率组之间差异和相同频率不同声强组之间差异,并分别测溶栓率与超声波频率及强度之间的关系。结果声强0.7W/cm2条件下,频率为0.5MHz、1MHz和2MHz的超声波有明确的溶栓效果,溶栓率与频率呈负相关(r1=1.000,P<0.01);频率2MHz条件下,声强为0.7W/cm2、1.4W/cm2和1.8W/cm2的超声波有明确效果,溶栓率与声强呈正相关(r2=0.980,P<0.05)。结论在一定条件下,超声波有明确的直接溶栓效果,并与频率和声强相关。诊断用超声波(频率2MHz、声强<2W/cm2)可能具有潜在的溶栓价值。

Objective To evaluate the effects of frequency and intensity of ultrasound on sonothrombolysis in vitro. Methods Fifty - six thrombi samples of whole blood from the healthy volunteers were formed by being incubated in 37℃ water bath for 2 hours. The samples were 5 irradiation groups and a control. The irradiation groups were respectively radiated by the pulse ultrasound at 0.7 W/cm^2 - 0.5 MHz, 0.7 W/cm^2 - 1 MHz, 0.7 W/cm^2 - 2 MHz, 1.4 W/cm^2 - 2 MHz and 1.8 W/cm^2 - 2 MHz for 10 minutes and the control was treated without ultrasound. The thrombolysis rates were caculated and compared between the groups. And the correlation between the thrombolysis rate and the frequency and the intensity of ultrasound were calculated by SPSS 10.0 software respectively. Results When the intensity was kept at 0.7 W/cm^2 , ultrasound of 0.5 MHz, 1 MHz and 2 MHz solved the thrombi obviously and there was a negative correlation between the thrombolysis rate and frequency （ r1 = 1.0（30, P 〈 0.01 ）. And when the frequency was kept at 2 MHz, ultrasound of 0.7 W/cm^2, 1.4 W/cm^2 and 1.8 W/cm^2 also solved the thrombi significantly and there was a positive correlation between the thrombolysis rate and the intensity （ r2 = 0. 980, P 〈 0.05 ）. Conclusion Ultrasound can lysis thrombi directively in certain conditions and its effect is related with the frequency and the intensity. Diagnostic ultrasound （2 MHz, 〈 2 W/cm^2 ） has potential to be applied in the treatment to thrombi.