Label-free optical imaging of 3D structural and functional microcirculations

描述(由申请人提供)：该项目的主要目标是开发一种新的高分辨率(10 5m)、实时和非侵入性的光学成像工具，能够在不使用标记技术的情况下，对深度达2 mm的扫描组织体积内的血流灌注和组织氧耗进行全面、同时和定量的评估。用于量化血流量和血氧的非侵入性和无标记成像技术--精确到毛细血管水平的分辨率--对于改善对周围血管受累的疾病的理解、诊断和治疗至关重要，如中风、创伤性脑损伤、出血、视网膜病变和癌症。目前还没有光学成像技术可以在体内微循环组织床内同时测量临界成像深度(&gt；1 mm)的血液灌注量和氧气消耗。建议的成像工具-功能光学微血管造影术(FOMAG)-是一种全面的、无标记的体积成像技术，旨在同时成像和量化扫描组织体积内的血液灌流和血氧状态。FOMAG将被设计成：1)通过分离从血流中反向散射的内源光学信号和从组织背景(即，大块静态组织)中反向散射的内源光学信号来成像详细的血管结构；2)通过使用新的多普勒OMAG技术来确定体积血流量。该技术基于光学fOMAG信号的相变与组织成像时血流速度之间的线性关系；3)通过一种新的光谱OMAG技术来映射血液灌流的氧合状态，该技术依赖于800 nm波长下氧化和去氧血红蛋白在近红外区域不同的摩尔消光系数。该项目将检验这一假设，即组织中的血液灌流和氧气消耗可以侵入性地、可靠地实时成像、量化和表征，组织深度为0到2毫米，分辨率为10 5米。该项目的具体目标是：1)构建fOMAG成像系统，2)开发新型相位分辨多普勒OMAG用于定量测量体积血流量，3)表征新型光谱OMAG用于成像血管内氧饱和度的特性，4)通过对小鼠脑血流灌注的体积成像验证fOMAG在体内的有效性，5)探讨fOMAG用于无创性经颅监测小鼠脑创伤后脑血管血流变化和愈合相关新生血管的应用。与公共健康相关：我们建议开发一种新的生物医学成像技术，功能光学微血管成像，它可以在体内非侵入性地提供对扫描的组织体积内的组织血流灌注和氧气消耗的同时、定量评估，并且不使用标记技术。这一新的成像技术将成为研究组织血液供应的重要工具，并可能有助于诊断、监测和治疗血管受累的疾病。

DESCRIPTION (provided by applicant): The primary objective for the proposed project is to develop a novel high-resolution (<10 5m), real-time and non-invasive optical imaging tool that is capable of comprehensive, simultaneous, and quantitative assessments of blood perfusion and tissue oxygen consumption within a scanned tissue volume up to 2 mm in depth without the use of labeling technique. Non-invasive and label-free imaging techniques for quantifying blood flow and blood oxygenation - down to capillary-level resolution - are of paramount importance for the improved understanding, diagnosis, and treatment of diseases that have peripheral vascular involvement, such as stroke, traumatic brain injury, hemorrhage, retinopathy, and cancer. Currently no optical imaging techniques are available that can offer simultaneous measurements of blood perfusion and oxygen consumption at a critical imaging depth (>1mm) within microcirculatory tissue beds in vivo. The proposed imaging tool - functional optical micro-angiography (fOMAG) - is a comprehensive and label- free volumetric imaging technology designed to simultaneously image and quantify blood perfusion and the oxygenation status of perfused blood within a scanned tissue volume. fOMAG will be designed to: 1) Image the detailed vessel architectures by separating endogenous optical signals backscattered from blood flow, from those endogenous optical signals backscattered from the tissue background (i.e. from bulk static tissue); 2) Determine volumetric blood flow by employing a novel Doppler OMAG technique. This technique is based on the linear relationship between phase-changes in the optical fOMAG signals and the blood flow velocity when fOMAG images the tissue; 3) Map the oxygenation status of the blood perfusion by a novel spectroscopic OMAG technique, which relies on the different molar extinction coefficients between the oxygenated and de- oxygenated hemoglobin in the near-infrared region at 800 nm wavelength band. The project will test the hypothesis that blood perfusion and oxygen consumption in tissues can be invasively and reliably imaged, quantified, and characterized simultaneously in real time, at 0- to 2-mm tissue depths and at a resolution of <10 5m. The specific aims of the project are to: 1) construct an fOMAG imaging system, 2) develop a novel phase- resolved Doppler OMAG to quantify volumetric blood flow, 3) characterize a novel spectroscopic OMAG to image oxygen saturation in blood vessels, 4) validate fOMAG In vivo by volumetric imaging of cerebral blood perfusion in mice, and 5) investigate the utility of fOMAG for non-invasive transcranial monitoring of changes in cerebrovascular blood flow and healing-associated neovascularization after traumatic brain injury in mice. PUBLIC HEALTH RELEVANCE: We propose to develop a novel biomedical imaging technology, functional optical micro-angiography that can provide the simultaneous, quantitative assessment of tissue blood perfusion and oxygen consumption within a scanned tissue volume in vivo non-invasively and without the use of labeling techniques. This novel imaging technique will become an important tool to investigate blood supply to tissues, and may help diagnosis, monitoring, and therapeutic interventions in diseases with vascular involvement.