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功能。虽然 preva- 借出的光学脑监测方法基于测量血氧水平依赖性（BOLD） 来自血液吸收的信号，光学方法测量来自装饰物的脑血流量（CBF） 相干光被血流散射时的关系可能提供一个有希望的替代方案。 CBF 测量对大脑具有更高的敏感性，并且与 BOLD 信号互补。他们的组合—— 国家可以提供更精确的神经活动图景，例如可以用于计算 大脑的代谢摄氧率。无创 CBF 测量也有助于 人脑功能神经成像，用于脑血管健康、认知衰老和神经元 紧张护理。然而，目前的光学CBF检测方法，如扩散相关光谱 Troscopy (DCS)、基于激光散斑的成像及其变体很容易发生脑外污染 国家。它们的深度灵敏度受到光子路径分布的限制。对于这款R21 项目中，我们建议开发和评估一种新颖的 CBF 测量方法，称为超声波- 标记远程干涉流量计（URIF），用于高灵敏度和选择性大脑活动的任务 质量监控。 URIF 与当前的光学 CBF 方法有很大不同。而目前的光学 CBF 方法测量来自所有光路的积分信号，其中信号光子具有 通过大脑活动部位的非信号光子淹没了，URIF se- 通过超声波标记和外差检测仅选择和相干放大信号光子 。更重要的是，凭借新颖的理论和实验框架，URIF 可以量化局部 CBF 位于毫米大小的大脑活动部位，深度达到一厘米及以上，消除了前 痕量脑污染并显着增强深度灵敏度、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 统计验证人脑模型上的 URIF。 URIF测量深度的性能指标 流量将根据准确性、灵敏度和选择性来确定。如果成功的话，该技术将 为大脑活动的远程流量测量开辟一条新途径，并填补现有的重要测量空白 光学和非光学方法还无法解决。