Non-invasive optical detection of cerebral hemodynamics and metabolic transients

项目概述：本项目旨在论证非侵入性光学测量的可行性。 血液动力学和代谢变化与脑激活有关的动态时间进程 受试者平均动脉压的变化和自发性血流动力学振荡。功能性 近红外光谱(FNIRS)是一种非侵入性的光学技术，可以测量大脑 氧合血红蛋白(O)和脱氧血红蛋白(D)的浓度。O和D变化的生物起源 包括以脑血容量(CBV)和脑血流量(CBF)描述的血液动力学变化，以及 用脑氧代谢率(CMRO2)描述的代谢变化。我们最近介绍了 一种新的血流动力学模型，可将CBV、CBF和CMRO2的动态变化转换为O和D 由fNIR测量的变化。它是一个考虑了动态的多隔室模型 与毛细血管和静脉血液转运时间相关的影响。因为我们的模型预测fNIR信号 根据CBF和CMRO2变化的差异，我们建议用测量来补充fNIRS 弥散相关光谱分析，这也是一种非侵入性的光学技术。我们 建议使用我们的新技术执行并发和协同本地化的fNIRS和分布式控制系统数据分析 血流动力学模型，以生成CBV、CBF和CMRO2的动态轨迹，描述血流动力学和 代谢的瞬变和波动。这是一种创新的方法，相对于 通常基于稳态模型的功能磁共振成像和光学成像领域，这些领域包括 本质上不适合研究瞬变条件。我们还假设一个宇宙动力学 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，具有独立的fNIR。我们将进行人体研究，以证明这一可行性 在被提议的表征大脑活动的方法中，对平均动脉压的受控扰动， 以及静息时的自发性血流动力学振荡。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，用于表征大脑的激活条件和休息状态 状态功能连通性。这样的工具可以显著影响功能神经成像研究并发现 神经血管疾病诊断与评估的临床应用。

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.