视网膜及脉络膜血流的三维成像与定量化研究

Retinal and choroidal blood circulation is essential for the human eye function. Eye diseases such as glaucoma,diabetic retinopathy and age-related macular degeneration are related to the status of blood circulation.In order to detect the abnormal fundus circulation in a timely manner and make a correct assessment, a noninvasive, noncontact three dimensional imaging technology with high spatial resolution and high velocity sensitivity is urgently required. In view of this, this project aims to study on three dimensional imaging and quantification of blood flow in retina and choroid. A full-range high speed spectral-domain Doppler optical coherence tomography (SD-OCT) system will be built for volumetric imaging of the blood flow in fundus. Method to obtain Doppler information with high velocity sensitivity is to be developed to realize the detection of minimum velocity beyond that determined by the noise floor by current phase-resolved method, and hence reliable detection of capillaries with blood flow at small velocity. Three dimensional imaging methods for structure, vasculature, and velocity are developed to provide structural image, capillaries network image, and velocity image. With the established system, three dimensional imaging and quantitative analysis will be conducted, and depth resolved visualization of the fundus blood perfusion and quantitative information including velocity, dimension of blood vessels and blood flow will be provided. This project will not only promote the development of Doppler OCT, but also advance eye-disease-diagnosis technology and ophthalmic instrumentation. It is of great scientific importance and clinical value.

视网膜及脉络膜的血循环对于人眼正常功能至关重要。眼科疾病如青光眼、糖尿病视网膜病变、老年性黄斑变性都与血循环状况有关。为实现眼底血循环异常的及时发现与正确评估，迫切需要一种无损伤、非接触、高空间分辨率与高速度灵敏度的三维成像技术。有鉴于此，本项目开展视网膜及脉络膜血流三维成像与定量化研究。建立全量程高速谱域多普勒ＯＣＴ系统，实现眼底血流的三维成像；发展多普勒流速信息的高灵敏度获取方法，突破现阶段噪声受限的速度探测灵敏度，实现低流速毛细血管的可靠探测；发展眼底组织结构、血管、流速的三维成像方法，提供结构图像、毛细血管网图像、血流速度分布图像；利用建立的成像系统，开展眼底血流的三维成像与定量化分析，实现深度分辨眼底血流灌注的可视化，实现血流速度、血管尺度、血流量信息的定量化。本项目研究不仅能促进多普勒ＯＣＴ技术的发展，而且能推动眼疾病诊断技术与眼科仪器的发展，具有重要的科学意义与临床应用价值。

本项目旨在发展眼底三维血管成像与定量化技术，建立全量程高速谱域OCT系统，研究血流信息高灵敏度获取方法，开展血流成像应用研究。项目完成了基于高速CMOS的高速光谱仪的研制，实现了三维成像扫描时序的精确控制与三维成像信号的高速采集。研究了全量程成像方法，研制了全眼扫描成像装置，建立全量程高速谱域OCT系统。研究了大动态范围血流信息的相位提取方法，提出了复数互相关大视场微血管造影新方法，发展了系列对比度增强方法。基于建立的系统，开展了血流成像应用实验。获得了高质量三维血管分布图像，实现了三维血管网的动态表征与定量分析。本项目发展的无标记高分辨三维成像技术，具有重要科学研究与临床应用价值。