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

描述（由申请人提供）：拟议项目的主要目标是开发一种新的高分辨率（<10米），实时和非侵入性光学成像工具，能够在不使用标记技术的情况下，在深度为2mm的扫描组织体积内全面，同步和定量评估血液灌注和组织耗氧量。用于量化血流和血氧的无创和无标签成像技术-低至毛细血管水平分辨率-对于改善对周围血管累及疾病的理解，诊断和治疗至关重要，例如中风，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同时测量体内微循环组织床内临界成像深度（bbb1mm）的血液灌注和耗氧量。所提出的成像工具-功能性光学微血管成像(fOMAG) -是一种全面且无标签的体积成像技术，旨在同时成像和量化扫描组织体积内的血液灌注和灌注血液的氧合状态。fOMAG将被设计为：1)通过从血流中分离反向散射的内源性光信号，从组织背景（即从大块静态组织）中分离反向散射的内源性光信号，对详细的血管结构进行成像；2)采用新型多普勒OMAG技术测定血流量。该技术基于fOMAG成像时光学信号的相位变化与血流速度之间的线性关系；3)利用800 nm波段近红外区氧合血红蛋白与脱氧血红蛋白之间不同的摩尔消光系数，利用新型光谱OMAG技术绘制血流灌注的氧合状态。该项目将测试这样一个假设，即组织中的血液灌注和氧气消耗可以在0- 2mm的组织深度和<10 5m的分辨率下，同时进行有创且可靠的成像、量化和实时表征。该项目的具体目标是：1)构建fOMAG成像系统；2)开发一种新型相分辨多普勒OMAG来量化容量血流量；3)表征一种新型光谱OMAG来成像血管中的氧饱和度；4)通过小鼠脑血流灌注的体积成像来验证fOMAG在体内的有效性；5)研究fOMAG在创伤性脑损伤后小鼠脑血管血流变化和愈合相关新生血管的无创经颅监测中的应用。公共卫生相关性：我们建议开发一种新的生物医学成像技术，功能性光学微血管造影，可以在体内无创和不使用标记技术的情况下，在扫描的组织体积内同时定量评估组织血液灌注和氧气消耗。这种新的成像技术将成为研究组织血液供应的重要工具，并可能有助于血管受累疾病的诊断、监测和治疗干预。

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.