肝灰阶超声造影剂量与效果关系的实验研究

Experimental study of rabbit liver with contrast gray-scale imaging-doses and effects

目的 探讨不同超声造影剂剂量对肝灰阶超声造影效果的影响及其变化规律。方法 分别对 5只新西兰大白兔在 8个剂量水平 (剂量范围 :0 .0 2～ 0 .16ml/kg)团注超声造影剂 ,应用低机械指数灰阶超声造影和时间强度曲线定量分析门静脉和肝实质造影增强效果。结果 门静脉和肝实质开始增强时间随造影剂剂量的增加而缩短 ,均呈指数递减形式 ;造影剂剂量与门静脉、肝实质峰值增强时间无明确相关性 (r =-0 .3 5 ,0 .2 2 ) ;在 0 .0 2～ 0 .10ml/kg范围内 ,造影剂剂量与门静脉、肝实质峰值信号强度呈直线相关关系 (r =0 .89,0 .92 ) ;门静脉和肝实质的平均渡越时间和曲线下面积均随造影剂剂量的递增而增加 ,呈指数递增形式。结论 超声造影剂剂量影响肝造影增强各参数。确定剂量和效果的关系及认识其规律是进行超声造影和定量研究的前提条件。 0 .10ml/kg是兔理想的造影剂量。

Objective To study the relationship between doses of ultrasound contrast agent(UCA) and contrast-enhancement effects of gray-scale imaging in rabbit liver. Methods Ultrasound contrast agent SonoVue TM in eight different doses ( 0.02 - 0.16 ml/kg) was applied respectively in five normal rabbits in randomized order as a bolus in a marginal ear vein followed by a 1.5 ml saline flush. Corresponding parameters of the time-intensity curve: time to enhancement(ET),time to peak intensity(PIT),peak signal intensity(PSI),mean transit time(MTT) and area under the curve(AUC) were measured using low mechanical index contrast gray-scale imaging and Wash-in/Wash-out time intensity curve software package. Results Along with an increase of the SonoVue TM dose,the MTT and the AUC increased exponentially,and the ET decreased exponentially. The PSI of portal vein and liver parenchyma increased only in the dose range from 0.02 ml/kg to 0.10 ml/kg ( r = 0.89 and 0.92 ,respectively),and decreased with a further increase of the UCA dose. A possible explanation for this effect is the bubble saturation and attenuation. No significant correlation was found between the UCA dose and the PIT( r = -0.35 and 0.22 ,respectively). Conclusions The parameters of time-intensity curve are influenced intensely by different UCA dose. It is important to grasp the relationship between the UCA doses and contrast-enhancement effects for microcirculatory quantification. The 0.10 ml/kg appears to be the optimal dose for tissue perfusion studying because it significantly improved videointensity and duration of enhancement and did not result in the bubble saturation and attenuation.