| Background and purposeIschemic stroke is the leading cause of high mortality and high disability in Chinese residents.Carotid atherosclerotic plaque rupture is an important factor leading to stroke.Therefore,the assessment of plaque vulnerability has important clinical significance.significance.Ultrasound uses gray-scale median(GSM)studies to show that the pathological tissue corresponding to hypoechoic plaques or hypoechoic plaques is lipid core or intraplaque hemorrhage,but it is difficult to distinguish the two under conventional ultrasound.In most studies on the evaluation of intraplaque neovascularization(IPN)by contrast-enhanced ultrasound,the contrast enhancement intensity in the hypoechoic area is higher,but the conclusions of different studies are different.In some studies,the enhancement of the hypoechoic area is not obvious.At present,carotid endarterectomy(CEA)and carotid artery stenting(CAS)are the main methods for the treatment of carotid artery stenosis.Studies have found that the large lipid core in the low echo plaque is an important cause of ipsilateral microembolization after CAS,and whether the plaque is homogeneous lipid core has a significant correlation with the prognosis of stent implantation.Therefore,it is of great clinical significance to identify the hypoechoic areas in plaque.At present,there is no report on the clinical study of contrast-enhanced ultrasound and pathological contrast of low echo plaque in differentiating bleeding and lipid components in plaque at home and abroad.The purpose of this study is to explore the application value of contrast-enhanced ultrasound in the differential diagnosis of hemorrhages and lipid components in the low echo area of carotid plaque.Objects and methodsMethods from August 2019 to October 2020,72 patients with moderate to severe carotid artery stenosis and carotid endarterectomy(CEA)in our hospital were selected.All patients underwent routine ultrasound and contrast-enhanced ultrasound examination.The routine ultrasound examination was low echo plaque or mixed echo plaque with low echo.According to the plaque characteristics and pathological morphology,the plaques were divided into lipid core group and intra-plaque hemorrhage group According to the lipid status,group A was divided into three groups:paste like lipid group,mud like lipid group and Sand like lipid group.General data and laboratory examination indexes of all subjects were collected,and the morphology and internal echo of plaques were recorded by routine ultrasound.Contrast-enhanced ultrasound plaque on classification and quantitative analysis using acoustic software ACQ plaques time intensity curve(TCI),record the patchs contrast arrival time(AT),time to peak intensity(TTP),peak intensity(PI),and calculate the patches enhanced intensity(EI)(El=PI-BI)and lumen intensity increased and the ratio of patches enhanced intensity(Ratio);The plaque was fixed with 10%formalin buffer solution after surgery.Continuous pathological sections of the area of interest were performed.Through HE staining and immunohistochemistry such as CD31,CD68 and SMA,the plaque components including the number of new blood vessels,the proportion of macrophages,the proportion of smooth muscle cells and the proportion of collagen were recorded.Statistical analysis was performed on the results between each group.Results1.Comparison of general conditions:there were no significant differences in age,gender,hypertension and other general information,as well as lipid indexes such as total cholesterol and triglyceride among all groups(P>0.05).2.Comparison between the lipid core group and the intra-plaque hemorrhage group:the plaque enhancement rate of the lipid core group was significantly higher than that of the intra-plaque hemorrhage group(P<0.05);PI,EI and Ratio in lipid core group were significantly higher than those in intra-plaque hemorrhage group(P<0.05).The proportion of necrotic matter in plaque,the proportion of macrophages and the density of neovascularization in lipid core group were significantly higher than those in intra-plaque hemorrhage group(P<0.05).There were no significant differences in plaque morphology,AT,TTP,smooth muscle cell percentage and collagen percentage between the two groups(P>0.05).3.Comparison of paste like lipid group,mud like lipid group,Sand like lipid group and intra-plaque hemorrhage group:the contrast grade of mud like lipid group was significantly different from that of intra-plaque hemorrhage group and Sand like lipid group(P<0.05);the contrast grade of paste like lipid group and mud like lipid group was significantly higher than that of intra-plaque hemorrhage group and Sand like lipid group(P<0.05).The PI、EI and Ratio were significantly higher than those in sand like lipid group and plaque intra-plaque hemorrhage(P<0.05).There was no significant difference between paste like lipid group and mud like lipid group,and between sand like lipid group and intra-plaque hemorrhage group(P>0.05);The proportion of necrotic substances in intra-plaque hemorrhage group was significantly higher than that in mud like lipid group,and the proportion of macrophages in mud like lipid group was significantly higher than that in intra-plaque hemorrhage group(P<0.05);the density of neovascularization in plaque of paste like lipid group and mud like lipid group was significantly higher than that of Sand like lipid group and intra-plaque hemorrhage group(P<0.05);The density of neovascularization in plaques of paste like lipid group and mud like lipid group was significantly higher than that of Sand like lipid group and intra-plaque hemorrhage group(P<0.05);there was no significant difference between paste like lipid group and mud like lipid group,Sand like lipid group and intra-plaque hemorrhage group(P>0.05).4.Correlation analysis:CEUS grade was significantly positively correlated with the density of new vessels in postoperative pathological plaques(r=0.76,P=0.00).Conclusions1.In the low echo area of plaque,the contrast grade of lipid core,PI,EI and Ratio were significantly higher than those of intra-plaque hemorrhage,in which paste like lipid and mud like lipid were significantly higher than those of intra-plaque hemorrhage and Sand like lipid.There was no significant difference between mud like lipid and paste like lipid,Sand like lipid and intra-plaque hemorrhage of plaque.2.The density of neovascularization in lipid core plaque was higher than that in intra-plaque hemorrhage.The density of neovascularization in different types of lipid was different,and the order was mud like lipid group,paste like lipid group and sand like lipid group from high to low.3.The proportion of macrophages in the lipid core plaque was significantly higher than that intra-plaque hemorrhage,and the proportion of necrotic matter was significantly lower than that intra-plaque hemorrhage.4.CEUS semi-quantitative classification was positively correlated with pathological neovascularization density,and CEUS could accurately evaluate the neovascularization density in plaques. |
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