兔动脉粥样硬化斑块超声造影参数与微血管密度的相关性研究

Correlation between parameters of contrast-enhanced ultrasound and microvessel density in rabbit atherosclerotic plaques

目的探讨兔动脉粥样硬化斑块超声造影参数与微血管密度（MVD）的相关性。方法26只雄性新西兰大白兔经球囊扩张损伤腹主动脉并高脂喂养12周后，常规超声检测到32个斑块，测量斑块的大小、管腔面积狭窄率及斑块厚度，运用实时超声造影技术对32个斑块进行超声造影检查，采用ACQ分析软件脱机进行声学定量分析，获取斑块的始增时间（AT）、到达时间（TTP）、峰值强度（PI）和基础强度（BI），计算增强强度（E1，E1=PI—BI）。行病理组织学检查及抗CD34免疫组化染色，计数微血管密度（MVD），分析其与造影参数的相关性，根据病理结果将斑块分为易损斑块和稳定型斑块。结果易损斑块组（13个）的EI和MVD均高于稳定型斑块组（19个），差异均有统计学意义[EI：（26．36±1．44）dB对（23．90±2．92）dB，t=-3．243，P=0．001；MVD：（5．23±1．16）／mm。对（2．47±1．12）／mm2，Z=-4．378，P〈O．001]。两组间斑块大小、管腔面积狭窄率、斑块厚度及超声造影参数PI、AT、TTP差异均无统计学意义（P〉0．05）；斑块的EI值与MVD呈显著正相关（r=0．676，P〈0．001）。结论超声造影参数EI值能较好地反映兔动脉斑块内的新生血管情况，有望作为临床评价斑块稳定性的的一项可靠指标。

Objective To evaluate the correlation between quantitative parameters of contrast- enhanced ultrasound（CEUS） and microvessel density （MVD） of rabbit atherosclerotic plaques. Methods Twenty-six male New Zealand rabbits were damaged abdominal aortic by balloon expanded,fed with high fat 12 weeks later. Thirty two plaques were detected using conventional ultrasound examination. The maximum area, luminal area stenosis rate and the maximum thickness of each plaque were recorded. CEUS was performed on 32 plaques and enhancement images were offline analyzed quantitatively by ACQ software and the parameters such as arrival time（AT）,time to peak（TTP）,basic intensity（BI）,and peak intensity（PI） were acquired. Enhanced intensity （El） was calculated according to the formula： EI = PI- BI. Then the experimental rabbits were killed for pathological examination and CD34 monoclonal antibody immunohistochemical detection. MVD was counted under the microscope. The correlation between the parameters of CEUS and MVD was analyzed. Based on pathological findings, the plaques were divided into vulnerable plaques and stable plaques. Results EI and MVD of vulnerable plaques group were significantly higher than that of stable plaques group [EI： （26.36 ± 1.44） dB vs （23.90 ± 2.92）dB, t = - 3. 243, P = 0.001 ; MVD： （5.23 ± 1. 16）/mm2 vs （2.47 ± 1.12）/ram2 , Z = - 4. 378, P d0. 0011. The maximum area, luminal area stenosis rate, the maximum thickness and PI, AT, TTP had no significant difference between two groups（ P〈0.05）. The value of E1 showed significant positive correlation with MVD （ r = 0. 676, P 〈0. 001 ）. Conclusions EI can accurately evaluate the angiogenesis of rabbit atherosclerotic plaques,which can be regarded as a useful index to distinguish between vulnerable and stable plaques.