Introduction: During exposure of the carotid arteries, embolism from the surgical site is recognized as a primary cause of neurological deficits or new cerebral ischemic lesions following carotid endarterectomy (CEA), and associations have been reported between histological neovascularization in the carotid plaque and both plaque vulnerability and the development of artery-to-artery embolism. Superb microvascular imaging (SMI) enables accurate visualization of neovessels in the carotid plaque without the use of intravenous contrast. This study aimed to determine whether preoperative SMI ultrasound for cervical carotid artery stenosis predicts the development of microembolic signals (MES) on transcranial Doppler (TCD) during exposure of the carotid arteries in CEA. Methods: Preoperative cervical carotid artery SMI ultrasound followed by CEA under TCD monitoring of MES in the ipsilateral middle cerebral artery was conducted in 70 patients previously diagnosed with internal carotid artery stenosis (defined as ≥70%). First, observers visually identified intraplaque microvascular flow (IMVF) signals as moving enhancements located near the surface of the carotid plaque within the plaque on SMI ultrasonograms. Next, regions of interest (ROI) were manually placed at the identified IMVF signals (or at arbitrary places within the plaque when no IMVF signals were identified within the carotid plaque) and the carotid lumen, and time-intensity curves of the IMVF signal and lumen ROI were generated. Ten heartbeat cycles of both time-intensity curves were segmented into each heartbeat cycle based on gated electrocardiogram findings and averaged with respect to the IMVF signal and lumen ROI. The difference between the maximum and minimum intensities (ID) was calculated based on the averaged IMVF signal (ID_IMVF) and lumen (ID_l) curves. Finally, the ratio of ID_IMVF to ID_l was calculated. Results: MES during exposure of the carotid arteries were detected in 17 patients (24%). The incidence of identification of IMVF signals was significantly greater in patients with MES (94%) than in those without (57%; p = 0.0067). The ID_IMVF/ID_l ratio was significantly greater in patients with MES (0.108 ± 0.120) than in those without (0.017 ± 0.042; p #x3c; 0.0001). The specificity and positive predictive value for the ID_IMVF/ID_l ratio for prediction of the development of MES were significantly higher than those for the identification of IMVF signals. Logistic regression analysis revealed that only the ID_IMVF/ID_l ratio was significantly associated with the development of MES (95% CI 101.1–3,628.9; p = 0.0048). Conclusion: Preoperative cervical carotid artery SMI ultrasound predicts the development of MES on TCD during exposure of the carotid arteries in CEA.
Cerebrovasc Dis Extra 2021;11:61–68

中文翻译：

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用于颈动脉狭窄的精湛微血管成像超声，用于预测颈动脉内膜切除术中颈动脉暴露期间经颅多普勒微栓塞信号的发展

介绍：在暴露颈动脉期间，手术部位的栓塞被认为是颈动脉内膜切除术 (CEA) 后神经功能缺损或新的脑缺血病变的主要原因，据报道颈动脉斑块中的组织学新生血管形成与两个斑块之间存在关联脆弱性和动脉对动脉栓塞的发展。卓越的微血管成像 (SMI) 能够在不使用静脉造影剂的情况下准确显示颈动脉斑块中的新血管。本研究旨在确定颈动脉狭窄术前 SMI 超声是否能预测 CEA 中颈动脉暴露期间经颅多普勒 (TCD) 上微栓塞信号 (MES) 的发展。方法：70 例既往诊断为颈内动脉狭窄（定义为≥70%）的患者在术前颈内动脉 SMI 超声后行 CEA，并在同侧大脑中动脉 MES 的 TCD 监测下进行。首先，观察者在视觉上将斑块内微血管流 (IMVF) 信号识别为 SMI 超声图上斑块内颈动脉斑块表面附近的移动增强信号。接下来，将感兴趣的区域 (ROI) 手动放置在已识别的 IMVF 信号处（或当颈动脉斑块内未识别出 IMVF 信号时位于斑块内的任意位置）和颈动脉腔，以及 IMVF 信号的时间强度曲线和产生了流明 ROI。根据门控心电图结果，将两条时间强度曲线的十个心跳周期分割成每个心跳周期，并根据 IMVF 信号和管腔 ROI 取平均值。基于平均 IMVF 信号 (ID) 计算最大和最小强度 (ID) 之间的差异_IMVF ) 和流明 (ID _l ) 曲线。最后，计算ID _IMVF与ID _l的比率。结果： 17 名患者（24%）在颈动脉暴露期间检测到 MES。MES 患者的 IMVF 信号识别发生率 (94%) 显着高于没有 MES 的患者 (57%；p = 0.0067)。MES 患者的 ID _IMVF /ID ₁比值 (0.108 ± 0.120) 显着高于没有 MES 的患者 (0.017 ± 0.042; p #x3c; 0.0001)。ID _IMVF /ID _l的特异性和阳性预测值预测 MES 发展的比率显着高于识别 IMVF 信号的比率。Logistic 回归分析显示，只有 ID _IMVF / ID _l比率与 MES 的发展显着相关（95% CI 101.1–3,628.9；p = 0.0048）。结论：术前颈动脉 SMI 超声可预测 CEA 暴露颈动脉期间 TCD 上 MES 的发展。
Cerebrovasc Dis Extra 2021；11:61–68