Non-invasive optical detection of cerebral hemodynamics and metabolic transients

项目概述：本项目旨在证明非侵入式光学测量的可行性， 与脑激活相关的血流动力学和代谢变化的动态时间过程， 平均动脉压的变化和人类受试者中自发的血液动力学振荡。功能 近红外光谱（fNIRS）是一种非侵入性的光学技术， 氧合血红蛋白（O）和脱氧血红蛋白（D）的浓度。O和D变化的生物学起源 包括由脑血容量（CBV）和脑血流量（CBF）描述的血液动力学变化，并且 脑氧代谢率（CMRO2）描述的代谢变化。我们最近推出了 将CBV、CBF和CMRO2的动态变化转化为O和D的新型血流动力学模型 通过fNIRS测量的变化。这是一个多室模型，考虑到动态 与毛细血管和静脉血液通过时间相关的影响。因为我们的模型预测fNIRS信号 根据CBF和CMRO2变化的差异，我们建议用测量补充fNIRS 的CBF与扩散相关光谱（DCS），这也是一种非侵入性的光学技术。我们 我建议用我们的新方法对并发和共定位的fNIRS和DCS数据进行分析。 血液动力学模型，以生成CBV、CBF和CMRO 2的动态轨迹， 代谢瞬变和波动。这是一个创新的做法，相对于目前的方法， 功能性MRI和光学成像领域通常基于稳态模型， 本质上不足以研究瞬态条件。我们还假设一种普遍的动力 可以识别光学测量的CBV和CBF之间的关系，以允许动态测量 CBV、CBF和CMRO2与独立fNIRS。我们将进行人体研究，以证明可行性 在所提出的表征大脑激活的方法中，控制对平均动脉压的扰动， 和静息时的自发血流动力学振荡。该项目将导致开发一个强大的 用于人脑功能研究的光学工具，以表征大脑激活条件和休息 状态功能连接。这样的工具可以显着影响功能神经成像研究，并发现 神经血管疾病的诊断和评估的临床应用。

Project Summary: This project aims to demonstrate the feasibility of non-invasive optical measurements of the dynamic time courses of hemodynamic and metabolic changes associated with brain activation, systemic changes in mean arterial pressure, and spontaneous hemodynamic oscillations in human subjects. Functional near-infrared spectroscopy (fNIRS) is a non-invasive optical technique that measures the cerebral concentrations of oxy-hemoglobin (O) and deoxy-hemoglobin (D). The biological origin of O and D changes includes hemodynamic changes described by cerebral blood volume (CBV) and cerebral blood flow (CBF), and metabolic changes described by the cerebral metabolic rate of oxygen (CMRO2). We have recently introduced a novel hemodynamic model that translates dynamic changes in CBV, CBF, and CMRO2 into O and D changes that are measured by fNIRS. It is a multi-compartment model that takes into account the dynamic effects associated with capillary and venous blood transit times. Because our model predicts that fNIRS signals depend on the difference of CBF and CMRO2 changes, we propose to complement fNIRS with measurements of CBF with diffuse correlation spectroscopy (DCS), which is also a non-invasive optical technique. We propose to perform the analysis of concurrent and co-localized fNIRS and DCS data with our new hemodynamic model to generate dynamic traces of CBV, CBF, and CMRO2 that describe hemodynamic and metabolic transients and fluctuations. This is an innovative approach with respect to current methods in the fields of functional MRI and optical imaging that are commonly based on steady state models, which are intrinsically inadequate for the study of transient conditions. We also hypothesize that a universal dynamic relationship between optically measured CBV and CBF can be identified to allow for dynamic measurements of CBV, CBF, and CMRO2 with stand-alone fNIRS. We will perform human studies to demonstrate the feasibility of the proposed methods to characterize brain activation, controlled perturbations to the mean arterial pressure, and spontaneous hemodynamic oscillations at rest. This project will result in the development of a powerful optical tool for the functional study of the human brain to characterize brain activation conditions and resting state functional connectivity. Such a tool can significantly impact functional neuroimaging research and find clinical applications in the diagnosis and assessment of neurovascular disorders.