颈动脉斑块长轴超声力学参数与组织病理学的相关性研究

A study on the correlation between ultrasonic mechanical parameters of the long axis and histopathology of carotid artery plaques

目的应用速度向量成像(velocity vector imaging,VVI)技术评价颈动脉硬化斑块力学参数,探讨力学参数与斑块内组织成分的相关性。方法选取2019年4-12月北京天坛医院拟行颈动脉内膜剥脱术(carotid endarterectomy,CEA)的患者53例,术前行VVI检查,将斑块于长轴方向自近心端向远心端均分为5部分,分别命名为R1、R2、R3、R4、R5,测量各节段斑块的力学参数(纵向应变、应变率),术后获得49例斑块,将大体标本与术前图像对应均分为5段,进行HE染色和CD68免疫组化分析。根据既往研究中不稳定斑块的病理诊断标准,将斑块分为不稳定组和稳定组,应用Image-Pro Plus 6.0图像分析软件计数斑块内巨噬细胞数量、脂质核心比例及CD68阳性反应区平均光密度。结果49例斑块中,33例为不稳定组,16例为稳定组。两组斑块的纵向应变及应变率(均数±标准差)为R1>R2>R5>R4>R3,巨噬细胞数量、平均光密度、脂质核心比例为R2>R3>R1>R4>R5,差异有统计学意义(均P<0.05),以上指标进行组间比较显示不稳定组大于稳定组,但差异无统计学意义(P>0.05)。斑块R1~R5段纵向应变与相应节段斑块内巨噬细胞数量、平均光密度、脂质核心含量之间呈正相关(r=0.300、0.255、0.394,P<0.05),应变率与相应节段斑块巨噬细胞数量、脂质核心含量之间呈正相关(r=0.199、0.214,P<0.05)。斑块上游R1~R2段相关系数r值较前增大(应变:r=0.480、0.418、0.582;应变率:r=0.292、0.319,P<0.05)。结论斑块各节段纵向应变及应变率与斑块内巨噬细胞、脂质核心含量之间呈正相关,斑块上游相关性更为显著,进而间接反映斑块长轴力学参数在判断斑块稳定性中具有一定价值。

Objective To evaluate the mechanical parameters of the carotid artery plaques using velocity vector imaging(VVI), and to investigate the correlations between the mechanical parameters and the histological components in the plaques.MethodsFifty-three patients undergoing carotid endarterectomy (CEA) from April to December, 2019 in Beijing Tiantan Hospital were selected and underwent VVI examination before operation. The plaques were divided into 5 parts along the long axis and named as R1, R2, R3, R4, R5, respectively. The mechanical parameters of the plaques in each region of interest were measured(longitudinal strain and strain rate). After operation, plaques were collected in 49 cases and the specimens were divided into five sections corresponding to preoperative images for HE staining and CD68 immunohistochemical analysis. According to the pathological diagnostic criteria of unstable plaques in previous studies, all plaques were divided into stable group and unstable group. Image-pro Plus 6.0 analysis software was used to measure the number of macrophages and the percentage of lipid core in plaques and the mean integral optical density of CD68 positive reaction area.Results Among 49 cases, 33 cases were for unstable group, 16 cases were stable group. The longitudinal strain and strain rate of two groups of patients were R1>R2>R5>R4>R3, the number of macrophages, mean integral optical density, and percentage of lipid core were R2>R3>R1>R4>R5, differences were statistically significant (P<0.05), the above indexes in unstable group were higher than in stable group, but there was no statistically significant difference (P>0.05). The longitudinal strain was positively correlated with the number of macrophages, mean integral optical density and lipid core content in the plaque(r=0.300, 0.255, 0.394 respectively, P<0.05), and the strain rate was positively correlated with the number of macrophages and lipid core content in the plaque(r=0.199, 0.214 respectively, P<0.05) and r values in R1-R2 were higher than in R1-R5(longitudinal strain: r=0.480, 0.418, 0.582;strain rate: r=0.292, 0.319, P<0.05).Conclusions The longitudinal strain and strain rate of the plaques are positively correlated with the macrophage and lipid core content of the plaques, and the r values of the upstream of plaques are higher. Therefore, VVI technique is valuable in detecting the stability of the plaques.