Numerical Investigation of Vasospasm Detection by Extracranial Blood Velocity Ratios.
Numerical Investigation of Vasospasm Detection by Extracranial Blood Velocity Ratios.
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通过颅外血流速度比检测血管痉挛的数值研究。
DOI：
10.1159/000454992
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Shadden,ShawnC
中科院分区：
文献类型：
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作者：
Ryu,Jaiyoung;Ko,Nerissa;Hu,Xiao;Shadden,ShawnC
背景：蛛网膜下腔出血后血管痉挛的早期诊断可以预防脑缺血和改善神经功能预后。本研究数值评估颅外血流速度指数检测vasospassion.Methods的相关性：脑血流的数值模型被用来评估与正常和受损的脑自动调节条件下的前部和后部血管痉挛的血流动力学。颅外血流速度在颈动脉和椎动脉和同侧和对侧，前和后，下游和上游的动脉之间的比例进行了监测vasospasm progression.Results：目前的临床指标，跟踪血管痉挛动脉段的血流速度，经颅多普勒（TCD），我们观察到，速度最初增加，然后随着血管痉挛的进展而下降。这种非单调行为可能导致中度至重度血管痉挛的假阴性决策。或者，受影响动脉的体积流量单调下降，导致血管痉挛动脉上游的血流速度也单调下降。基于这一原则，我们证明，颈动脉和椎动脉之间的速度比可以更好地识别中度至重度血管痉挛，提高血管痉挛detection.Conclusion.The速度指数在这项研究中提出的，可以使新的或改进的无创诊断血管痉挛颅外多普勒超声。与目前的临床指标相比，新指标可改善以下情况的处理：（1）严重血管痉挛或脑自动调节受损的情况，（2）血压和心输出量的全身变化，（3）发生在脑环区域远端动脉中的血管痉挛，以及（4）TCD骨声窗不足的情况。本研究结果为今后临床评价颅外指标检测血管痉挛提供了具体依据。
Background:Early diagnosis of vasospasm following subarachnoid hemorrhage can prevent cerebral ischemia and improve neurological outcomes. This study numerically evaluates the relevance of extracranial blood velocity indices to detect vasospasm.Methods:A numerical model of cerebral blood flow was used to evaluate the hemodynamics associated with anterior and posterior vasospasm under normal and impaired cerebral autoregulation conditions. Extracranial blood velocities at the carotid and vertebral arteries and their ratios between ipsilateral and contralateral, anterior and posterior, and downstream and upstream arteries were monitored during vasospasm progression.Results:For current clinical indices that track blood velocities at vasospastic arterial segments using transcranial Doppler (TCD), we observed that velocities increased initially and then decreased with vasospasm progression. This nonmonotonic behavior can lead to false-negative decisions in moderate to severe vasospasm. Alternatively, volumetric flow decreased monotonically at the affected arteries, leading to blood velocities upstream of the vasospastic artery also decreasing monotonically. Based on this principle, we demonstrate that velocity ratios between the carotid and vertebral arteries may better identify moderate to severe vasospasm and improve sensitivity and specificity of vasospasm detection.Conclusion.The velocity indices proposed in this study may enable new or improved noninvasive diagnosis of vasospasm using extracranial Doppler ultrasound. Compared to current clinical indices, the new indices may improve the handling of (1) scenarios of severe vasospasm or impaired cerebral autoregulation, (2) systemic changes in blood pressure and cardiac output, (3) vasospasm occurring in arteries distal to the cerebral circle region, and (4) cases with insufficient acoustic bone window for TCD. The results provide a concrete basis for future clinical evaluation of extracranial indices for vasospasm detection.