Meyer Tom, Kreft Bernhard, Bergs Judith, Antes Erik, Anders Matthias S, Wellge Brunhilde, Braun Jürgen, Doyley Marvin, Tzschätzsch Heiko, Sack Ingolf
Department of Radiology, Charité-University Medicine Berlin, Berlin, Germany.
Institute of Medical Informatics, Charité-University Medicine Berlin, Berlin, Germany.
Front Bioeng Biotechnol. 2023 Aug 15;11:1140734. doi: 10.3389/fbioe.2023.1140734. eCollection 2023.
Cerebral pulsation is a vital aspect of cerebral hemodynamics. Changes in arterial pressure in response to cardiac pulsation cause cerebral pulsation, which is related to cerebrovascular compliance and cerebral blood perfusion. Cerebrovascular compliance and blood perfusion influence the mechanical properties of the brain, causing pulsation-induced changes in cerebral stiffness. However, there is currently no imaging technique available that can directly quantify the pulsation of brain stiffness in real time. Therefore, we developed non-invasive ultrasound time-harmonic elastography (THE) technique for the real-time detection of brain stiffness pulsation. We used state-of-the-art plane-wave imaging for interleaved acquisitions of shear waves at a frequency of 60 Hz to measure stiffness and color flow imaging to measure cerebral blood flow within the middle cerebral artery. In the second experiment, we used cost-effective lineby-line B-mode imaging to measure the same mechanical parameters without flow imaging to facilitate future translation to the clinic. In 10 healthy volunteers, stiffness increased during the passage of the arterial pulse wave from 4.8% ± 1.8% in the temporal parenchyma to 11% ± 5% in the basal cisterns and 13% ± 9% in the brain stem. Brain stiffness peaked in synchrony with cerebral blood flow at approximately 180 ± 30 ms after the cardiac R-wave. Line-by-line THE provided the same stiffness values with similar time resolution as high-end plane-wave THE, demonstrating the robustness of brain stiffness pulsation as an imaging marker. Overall, this study sets the background and provides reference values for time-resolved THE in the human brain as a cost-efficient and easy-touse mechanical biomarker associated with cerebrovascular compliance.
脑搏动是脑血流动力学的一个重要方面。心脏搏动引起的动脉压变化导致脑搏动，这与脑血管顺应性和脑血流灌注有关。脑血管顺应性和血流灌注影响大脑的力学特性，导致搏动引起的脑硬度变化。然而，目前尚无成像技术能够直接实时定量脑硬度的搏动。因此，我们开发了非侵入性超声时间谐波弹性成像（THE）技术，用于实时检测脑硬度搏动。我们使用先进的平面波成像以60Hz的频率交错采集剪切波来测量硬度，并使用彩色血流成像来测量大脑中动脉内的脑血流。在第二个实验中，我们使用经济高效的逐行B模式成像来测量相同的力学参数，而不进行血流成像，以促进未来向临床的转化。在10名健康志愿者中，动脉脉搏波通过期间，颞叶实质的硬度从4.8%±1.8%增加到基底池的11%±5%和脑干的13%±9%。脑硬度在心脏R波后约180±30ms与脑血流同步达到峰值。逐行THE提供了与高端平面波THE相似的时间分辨率和相同的硬度值，证明了脑硬度搏动作为成像标志物的稳健性。总体而言，本研究为人类大脑中的时间分辨THE奠定了背景，并提供了参考值，作为一种经济高效且易于使用的与脑血管顺应性相关的力学生物标志物。
