Department of Stroke Center, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, China.
Transl Stroke Res. 2021 Feb;12(1):49-56. doi: 10.1007/s12975-020-00825-w. Epub 2020 Jun 29.
A significant portion of ischemic stroke is on account of emboli caused by fibrous cap rupture of vulnerable plaque with intraplaque neovascularization as a significant triggering factor to plaque vulnerability. Contrast-enhanced ultrasound (CEUS) could offer detailed information on plaque surface and intraplaque microvascular. This study aims to comprehensively assess the value of CEUS for the detection of plaque rupture and neovascularization in histologically verified plaques that had been removed from the patients who had undergone carotid endarterectomy (CEA). Fifty-one consecutive subjects (mean age, 67.0 ± 6.5 years; 43 [84.3%] men) scheduled for CEA were recruited. Standard ultrasound and CEUS were performed prior to surgery. Based on the direction of the contrast agents that diffuse within the plaques, plaques were divided as "inside-out" direction (contrast agents diffuse from the artery lumen towards the inside of the plaque) and non-inside-out direction. Plaque enhancement was assessed by using a semi-quantitative grading scale (grade 1: no enhancement; grade 2: moderate enhancement; grade 3: extensive enhancement). Plaques were evaluated for histopathologic characteristics according to Oxford Plaque Study (OPS) standard postoperative. Intraplaque neovascularization as manifested by the appearance of CD34-positive microvessels was characterized in terms of microvessel density (MVD), microvessel area (MVA), and microvessel shape (MVS). In 51 plaques, the sensitivity, specificity, positive, and negative predictive values of contrast agent inside-out direction diffusion for the detection of plaque fibrous cap rupture were 87.5%, 92.6%, 91.3%, and 89.3%, respectively. The incidence of cap rupture was significantly higher in contrast agent inside-out direction diffusion than non-inside-out direction diffusion (73.9% vs 25.0%, p < 0.001), and inside-out direction diffusion did exhibit higher frequency of vulnerable plaques (OPS grades 3-4) (95.7% vs 53.6%, p = 0.001). Multivariate logistic regression analysis revealed the contrast agent inside-out direction diffusion as an independent correlate to plaque rupture (OR 8.5, 95% CI 2.4-30.1, p = 0.001). With increasing plaque enhancement, plaque MVD (p < 0.001), plaque MVA (p = 0.012), and percentage of highly irregular-shaped microvessels increased (p < 0.001). Contrast agent inside-out direction diffusion could indicate plaque rupture. The increase in plaque enhancement paralleled increased, larger, and more irregular-shaped microvessels, which may suggest an increased risk of plaque vulnerability.
对比增强超声研究
相当一部分缺血性脑卒中是由于易损斑块的纤维帽破裂引起的栓塞所致，斑块内新生血管是斑块易损性的一个重要触发因素。对比增强超声（CEUS）可提供斑块表面和斑块内微血管的详细信息。本研究旨在全面评估 CEUS 检测经颈动脉内膜切除术（CEA）切除患者斑块内破裂和新生血管的价值。
连续招募了 51 名（平均年龄 67.0±6.5 岁；43 [84.3%] 名男性）计划行 CEA 的患者。手术前进行了标准超声和 CEUS 检查。根据对比剂在斑块内扩散的方向，将斑块分为“由内而外”方向（对比剂从动脉管腔向斑块内部扩散）和非由内而外方向。使用半定量分级量表评估斑块增强程度（1 级：无增强；2 级：中度增强；3 级：广泛增强）。根据牛津斑块研究（OPS）标准术后对斑块进行组织病理学特征评估。根据 CD34 阳性微血管的出现，将斑块内新生血管描述为微血管密度（MVD）、微血管面积（MVA）和微血管形态（MVS）。在 51 个斑块中，对比剂由内而外扩散对检测斑块纤维帽破裂的敏感性、特异性、阳性预测值和阴性预测值分别为 87.5%、92.6%、91.3%和 89.3%。与非由内而外扩散相比，由内而外扩散的帽破裂发生率明显更高（73.9% vs 25.0%，p<0.001），由内而外扩散显示出更高比例的易损斑块（OPS 分级 3-4）（95.7% vs 53.6%，p=0.001）。多变量逻辑回归分析显示，对比剂由内而外扩散是斑块破裂的独立相关因素（OR 8.5，95%CI 2.4-30.1，p=0.001）。随着斑块增强程度的增加，斑块 MVD（p<0.001）、斑块 MVA（p=0.012）和高度不规则形状微血管的百分比增加（p<0.001）。对比剂由内而外扩散可提示斑块破裂。斑块增强程度的增加与更大、更不规则形状的微血管平行增加，这可能表明斑块易损性增加的风险。
