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模式， 原位和真实的实时地对生物组织中的微观结构进行横截面成像。由于高轴向 由于光学相干断层扫描具有高分辨率，因此光学相干断层扫描非常适合于对具有层状结构的组织（例如视网膜）进行成像。最近 在过去5年中，OCT技术的进步使得OCT成像速度和 灵敏度重要的是，高速OCT能够实现快速体积成像，并促进新的成像源。 该建议的中心目标是OCT的进步 技术将使深度分辨，定量血流动力学和代谢测量， 大脑中的功能激活具有高时空分辨率。该提案将开发新的 用于增强OCT定量测量血流，血容量， 血细胞比容氧饱和度和毛细血管扩张将这些技术和方法应用于研究 在躯体感觉激活期间的神经血管耦合和氧消耗。具体目标是 方案有：1.开发用于脑成像的高速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 波长，将被开发。2.开发并验证血流量、血容量、 OCT定量测量血细胞比容、氧饱和度和毛细血管扩张的方法 将开发血液动力学。这些方法将在循环全血样本中进行体外验证， 并与双光子显微镜和光学固有信号成像（OISI）进行了比较。这一目标将 表征OCT相对于用于测量皮质骨的其他成像技术的性能 血流动力学3.表征层流反应并量化功能性期间的耗氧量 activation.目标2中开发的方法将用于表征皮质血流动力学反应 根据血管区室和皮质层，并定量测定氧消耗量， 躯体感觉激活该计划的结果将回答有关 在微观水平上的血流动力学和代谢反应，这将有助于解释宏观 测量，如BOLD功能磁共振成像，并提高对脑血管生理和病理的理解。

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.