Functional Optical Coherence Tomography for Imaging of Cortical Hemodynamics

摘要 光学相干层析成像(OCT)是一种可以进行微米级、层析成像的光学成像方式 原位和实时的生物组织中微结构的横断面成像。由于高轴向 分辨率高，OCT非常适合具有层状结构的组织成像，如视网膜。近期 在过去的5年中，OCT技术的进步使OCT成像速度和 敏感度。重要的是，高速OCT实现了快速体积成像，并促进了新的来源 对比度，如多普勒和光谱OCT。这项提案的一个核心目标是，10月的进展 技术将使深度分辨的、定量的血流动力学和代谢测量在 具有高时空分辨率的大脑功能激活。这项提议将使小说 提高OCT定量测量血流量、血容量、 红细胞压积、血氧饱和度和毛细血管扩张。这些技术和方法将被应用于研究 躯体感觉激活过程中的神经血管偶联和氧耗。这样做的具体目的是 主要研究内容有：1.研制用于脑成像的高速OCT显微镜平台。双谱/傅立叶域 OCT显微镜平台，一个工作在近红外波长，另一个工作在可见光 波长，将被开发出来。2.制定和验证血液流量、血容量、 用OCT测定红细胞压积、血氧饱和度和毛细血管扩张。皮质骨的定量测量方法 血液动力学将得到发展。这些方法将在体外循环全血样本中进行验证， 并与双光子显微镜和光学本征信号成像(OISI)进行了比较。这一目标将 描述OCT相对于其他用于测量皮质的成像技术的性能 血流动力学。3.表征层流反应并量化功能过程中的氧气消耗 激活。在Aim 2中开发的方法将用于表征皮质血流动力学反应。 根据血管间隔和皮质层，定量测量氧耗 躯体感觉激活。这一计划的结果将回答关于 微观层面的血流动力学和代谢反应，这将有助于对宏观的解释 测量，如BOLD功能磁共振成像，并提高对脑血管生理学和病理学的了解。

ABSTRACT Optical coherence tomography (OCT) is an optical imaging modality that can perform micron scale, tomographic cross-sectional imaging of microstructure in biological tissues in situ and in real time. Due to the high axial resolution, OCT is ideally suited for imaging tissues with a laminar structure, such as the retina. Recent advances in OCT technology over the past 5 years have enabled dramatic advances in OCT imaging speed and sensitivity. Importantly, high-speed OCT enables rapid volumetric imaging, and facilitates new sources of contrast such as Doppler and spectroscopic OCT. A central goal of this proposal is that the advances in OCT technology will enable depth-resolved, quantitative hemodynamic and metabolic measurements during functional activation in the brain with high spatiotemporal resolution. This proposal will develop novel technologies and methods to enhance the capability of OCT to quantitatively measure blood flow, blood volume, hematocrit, oxygen saturation, and capillary dilation. These technologies and methods will be applied to study neurovascular coupling and oxygen consumption during somatosensory activation. The specific aims of this program are: 1. Develop high-speed OCT microscope platforms for brain imaging. Two spectral / Fourier domain OCT microscope platforms, one operating at near-infrared wavelengths and the other operating at visible wavelengths, will be developed. 2. Develop and validate methods of measuring of blood flow, blood volume, hematocrit, oxygen saturation and capillary dilation with OCT. Methods of quantitatively measuring cortical hemodynamics will be developed. These methods will be validated in vitro in circulating whole blood samples, and in vivo by comparison with two photon microscopy and optical intrinsic signal imaging (OISI). This aim will characterize the performance of OCT relative to other imaging technologies used for measuring cortical hemodynamics. 3. Characterize the laminar response and quantify oxygen consumption during functional activation. The methods developed in Aim 2 will be used to characterize the cortical hemodynamic response according to vascular compartment and cortical layer, and to quantitatively measure oxygen consumption during somatosensory activation. The results of this program will answer fundamental questions about the hemodynamic and metabolic responses at the microscopic level, which will aid interpretation of macroscopic measurements such as BOLD fMRI and improve understanding of cerebrovascular physiology and pathology.