Ultrasonic-tagged remote interferometric flowmetry for brain activity

用于大脑活动的超声波标记远程干涉流量测量

• 批准号: 10731255
• 负责人: Min Xu
• 金额: $ 22.41万
• 依托单位: HUNTER COLLEGE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10731255
• 关键词: Address; Blood; Blood flow; Brain; Brain imaging; Caring; Cerebrovascular Circulation; Cerebrovascular Disorders; Cerebrum; Cognitive aging; Detection; Diffusion; Flowmetry; Focused Ultrasound; Functional Magnetic Resonance Imaging; Goals; Holography; Human; Image; Laser Speckle Imaging; Lasers; Light; Lighting; Measurement; Measures; Metabolic; Methods; Monitor; Monte Carlo Method; Nature; Noise; Optical Methods; Optics; Outcome; Oxygen; Performance; Photons; Process; Research; Research Design; Resolution; Scheme; Signal Transduction; Site; Spectrum Analysis; Structure; Technology; Tissue imaging; Tissues; Ultrasonics; Variant; Work; absorption; biological systems; blood flow measurement; blood oxygen level dependent; brain size; cerebrovascular health; cost; detection method; electric field; experimental study; hemodynamics; heterodyning; imaging platform; innovation; metabolic rate; millimeter; neural; neuroimaging; non-invasive imaging; novel; portability; quantum; real time monitoring; ultrasound; uptake

Optical monitoring of brain activities is intrinsically associated with various operational advantages, including low-cost and portable noninvasive bedside continuous monitoring capabilities. While the preva- lent optical brain monitoring methods are based on measuring blood oxygenation level-dependent (BOLD) signals from blood absorption, optical methods measuring cerebral blood flow (CBF) from the decor- relation of coherent light when scattered by the blood flow may provide a promising alternative. CBF measurement has higher sensitivity to the brain and is complementary to BOLD signals. Their combi- nation can provide a more precise picture of neural activity and may be, for example, used to compute the metabolic oxygen uptake rate in the brain. Noninvasive CBF measurement is also instrumental for functional neuroimaging of the human brain for cerebrovascular health, cognitive aging, and neuroin- tensive care. However, the current optical CBF detection methods, such as diffusion correlation spec- troscopy (DCS), laser speckle-based imaging, and their variants, are prone to extracerebral contami- nation. They are limited in depth sensitivity relying on the distribution of the photon paths. For this R21 project, we propose to develop and evaluate a novel CBF measurement method, known as ultrasonic- tagged remote interferometric flowmetry (URIF), for the task of high sensitivity and selectivity brain activ- ity monitoring. URIF is substantially different from current optical CBF methods. Whereas current optical CBF methods measure an integrated signal from all optical paths in which the signal photons that have passed through the brain activity site are overwhelmed by non-signal photons that have not, URIF se- lects and coherently amplifies only the signal photons through ultrasonic tagging and heterodyne detec- tion. More importantly, with a novel theoretical and experimental framework, URIF can quantify the local CBF at the millimeter-size brain activity site at depths reaching one centimeter and beyond, removing ex- tracerebral contamination and significantly enhancing depth sensitivity, selectivity, and spatial resolution. Local absorption variation associated with hemodynamics can also be monitored simultaneously. We propose first to develop URIF using single-shot off-axis holography and then numerically and experimen- tally validate URIF on human brain phantoms. The performance metrics of URIF for measuring deep flow will be determined in terms of accuracy, sensitivity, and selectivity. If successful, the technology will pave a novel avenue for remote flowmetry of brain activity and fill a vital measurement gap that existing optical and non-optical methods have not been able to address.

大脑活动的光学监测本质上与各种操作优势相关， 包括低成本和便携式无创床边连续监测能力。虽然preva- 另一种光学脑监测方法是基于测量血氧水平依赖（BOLD） 来自血液吸收的信号，测量来自decor的脑血流量（CBF）的光学方法， 当被血流散射时相干光的关系可以提供有希望的替代方案。CBF 测量对大脑具有更高的灵敏度，并且与BOLD信号互补。他们的组合- Nation可以提供神经活动的更精确的图像，并且可以例如用于计算 大脑的代谢氧摄取率。无创CBF测量也有助于 脑血管健康、认知老化和神经功能的人脑功能性神经成像， 紧张的护理。然而，目前的光学CBF检测方法，如扩散相关光谱， 显微镜检查（DCS），基于激光斑点的成像及其变体，易于发生脑外污染， 民族它们在依赖于光子路径的分布的深度灵敏度方面是有限的。对于R21 项目中，我们建议开发和评估一种新型CBF测量方法，称为超声- 标记的远程干涉流量计（URIF），用于高灵敏度和选择性脑活动的任务， 城市监控URIF与目前的光学CBF方法有很大的不同。而目前的光学 CBF方法测量来自所有光路的积分信号，在所有光路中， 通过大脑活动部位的光子被没有信号的光子淹没，URIF se- 通过超声波标记和外差检测，选择并相干放大信号光子， 是的。更重要的是，通过一个新的理论和实验框架，URIF可以量化当地的 CBF在毫米大小的大脑活动部位的深度达到一厘米及以上，除去前， 脑污染，并显着提高深度灵敏度，选择性和空间分辨率。 还可以同时监测与血流动力学相关的局部吸收变化。我们 建议首先使用单次离轴全息术开发URIF，然后进行数值和实验- 在人脑模型上验证URIF。URIF用于测量深度的性能指标 将根据准确度、灵敏度和选择性来确定流量。如果成功，这项技术将 为大脑活动的远程流量测量开辟了一条新的途径，填补了现有的重要测量空白， 光学和非光学方法还不能解决。