Objective

Plaque elasticity and intraplaque neovascularisation are strongly suggestive of vulnerable plaque. This study aimed to investigate the relationship between intraplaque neovascularisation and plaque elasticity, and to compare the ultrasound findings with histopathological changes.

Methods

Patients enrolled in this study presented with symptomatic carotid stenosis (> 70%) and later underwent both pre-operative ultrasonography and endarterectomy. Contrast enhanced ultrasound (CEUS) and shear wave elastography (SWE) were used to measure the neovascularisation and elasticity of the plaque, respectively. After removal, plaques were histologically assessed to determine the microvessel density (MVD), matrix metalloproteinase (MMP)-9 expression, and type I/type III collagen ratio using immunohistochemistry staining and morphometry. A correlation analysis was used to establish the relationship among the aforementioned quantitative parameters. Inter- and intra-observer consistency evaluations were performed using the intraclass correlation coefficient and Bland–Altman plots.

Results

Ninety-four symptomatic patients with 98 plaques were included. The area under the curve (AUC) of the carotid plaque detected using CEUS correlated with its shear wave velocity (SWV) (r = –.714; p < .001), MVD (r = .842; p < .001), collagen type I/III ratio (r = –.833; p < .001), and MMP-9 (r = .738; p < .001). SWE was positively correlated with the type I/III collagen ratio (r = .805; p < .001). The overall interexaminer consistency of the SWE was acceptable (r = .638; p < .001). The interobserver correlation coefficient of the AUC, time to peak (TP), mean transit time (MTT), and SWV were .719, .756, .733, and .686, respectively. The intra-observer variability values of the AUC, TP, MTT, and SWV were .826, .845, .633, and .748, respectively.

Conclusion

SWE and CEUS can comprehensively evaluate the vulnerability of the carotid plaque by assessing the elasticity of the plaque and neovascularisation within it. The negative correlation between the intraplaque neovascularisation and elasticity, further validated by histological findings, suggests that the more abundant the neovascularisation, the less elasticity.

中文翻译：

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颈动脉超声的斑块弹性和斑块内新生血管形成：比较组织学研究

客观的

斑块弹性和斑块内新生血管形成强烈提示易损斑块。本研究旨在研究斑块内新生血管形成与斑块弹性之间的关系，并将超声结果与组织病理学变化进行比较。

方法

参加本研究的患者表现为有症状的颈动脉狭窄 (> 70%)，随后接受了术前超声检查和动脉内膜切除术。对比增强超声 (CEUS) 和剪切波弹性成像 (SWE) 分别用于测量斑块的新血管形成和弹性。去除后，对斑块进行组织学评估，以确定微血管密度 (MVD)、基质金属蛋白酶 (MMP)-9 表达和使用免疫组织化学染色和形态测量的 I/III 型胶原比率。相关分析用于建立上述定量参数之间的关系。使用组内相关系数和 Bland-Altman 图进行观察者间和观察者内部一致性评估。

结果

包括 94 名有症状的患者，有 98 个斑块。使用 CEUS 检测到的颈动脉斑块的曲线下面积 (AUC) 与其剪切波速度 (SWV) ( r  = –.714; p < .001)、MVD ( r  = .842; p < .001) 相关， I/III 型胶原蛋白比率 ( r  = –.833; p < .001) 和 MMP-9 ( r  = .738; p < .001)。SWE 与 I/III 型胶原比率呈正相关（r  = .805；p < .001）。SWE 的总体考官间一致性是可以接受的 ( r  = .638; p< .001）。AUC、达峰时间 (TP)、平均传输时间 (MTT) 和 SWV 的观察者间相关系数分别为 0.719、0.756、0.733 和 0.686。AUC、TP、MTT 和 SWV 的观察者内变异值分别为 0.826、0.845、0.633 和 0.748。

结论

SWE 和 CEUS 可以通过评估斑块的弹性和其中的新生血管形成来综合评估颈动脉斑块的脆弱性。组织学发现进一步证实了斑块内新生血管形成和弹性之间的负相关性表明新生血管形成越丰富，弹性越小。