Functional and Structural Optical Coherence Tomography for Glaucoma

描述(申请人提供)：青光眼是导致失明的主要原因。青光眼的早期诊断和密切监测很重要，因为青光眼的发病是隐蔽的，损害是不可逆转的。在过去的20年里，光学相干断层扫描(OCT)等先进的成像手段被用于改善青光眼的客观评估。OCT具有较高的轴向空间分辨率，在青光眼损害的神经结构测量中具有较好的诊断准确性和重复性。然而，单独测量结构，结合任何成像方式，对检测早期青光眼的敏感性有限，与视野(VF)损失的相关性仅为中等。利用高速OCT系统，我们开发了新的方法来成像和测量视神经头(ONH)和视网膜血流量。初步结果表明，OCT测量的VF丢失与视网膜血流量的相关性比OCT或其他成像手段测量的任何神经结构更高。因此，该项目的目标是通过进一步开发使用超高速(70-100 kHz)OCT技术的新的功能性OCT测量来提高青光眼的诊断和预后评估。具体目的是：1.改进视网膜血流的多普勒OCT测量方法。视网膜乳头周围动脉和静脉的多环扫描测量总视网膜血流量I，2秒。更快的OCT系统的使用将使自动化测量具有更好的重复性。2.建立ONH的OCT定量血管成像技术。利用一种新的分裂谱幅度-去相关算法，实现了三维OCT血管成像(3x3 mm扫描在3秒内)。初步结果显示，在早期青光眼中，ONH微循环显著丧失。计划在血管造影术、分割、量化和自动化方面进行算法改进。3.测量从ONH到视网膜神经节细胞的神经结构。通过登记几次体积扫描，我们已经展示了从ONH到黄斑的视网膜纤维通路的完整3D特征。将开发这些结构的全自动量化。4.评估先进的OCT技术在临床研究中的应用。功能性和结构性OCT在青光眼中的应用将通过对150名青光眼和健康受试者的纵向观察研究来评估。将在40名受试者中研究降眼压手术对血流的影响。视网膜血流量、ONH循环、视盘边缘体积、视乳头周围神经纤维层体积、黄斑神经节细胞复合体体积都是同一个青光眼拼图的碎片。该项目将开发新的成像方法，使我们能够使用一种工具-超高速OCT来查看整个图像。

DESCRIPTION (provided by applicant): Glaucoma is a leading cause of blindness. Early diagnosis and close monitoring of glaucoma are important because the onset is insidious and the damage is irreversible. Advanced imaging modalities such as optical coherence tomography (OCT) have been used in the past 2 decades to improve the objective evaluation of glaucoma. OCT has higher axial spatial resolution than other posterior eye imaging modalities, and it has relatively good diagnostic accuracy and reproducibility in the measurement of neural structures damaged by glaucoma. However, the measurement of structure alone, with any imaging modality, has limited sensitivity for detecting early glaucoma and only moderate correlation with visual field (VF) loss. Using high-speed OCT systems, we have developed new methods to image and measure optic nerve head (ONH) and retinal blood flow. Preliminary results showed that VF loss was more highly correlated with retinal blood flow as measured by OCT than any neural structure measured by OCT or other imaging modality. Accordingly, the goal of the proposed project is to improve the diagnostic and prognostic evaluation of glaucoma by further developing novel functional OCT measurements using ultrahigh-speed (70-100 kHz) OCT technology. The specific aims are: 1. Improve Doppler OCT measurement of retinal blood flow. Multi-circular scans of peripapillary retinal arteries and veins measure total retinal blood flow i 2 seconds. The use of faster OCT systems will allow automated measurement with improved reproducibility. 2. Develop quantitative OCT angiography of the ONH. Three dimensional (3D) OCT angiography has been made practical (3x3 mm scan in 3 seconds) by a novel split-spectrum amplitude-decorrelation algorithm. Preliminary results showed dramatic loss of ONH microcirculation in early glaucoma. Algorithmic improvement in angiography, segmentation, quantification, and automation are planned. 3. Measure nerve structure from the ONH to retinal ganglion cells. By registering several volumetric scans, we have demonstrated complete 3D characterization of the retinal fiber pathway from the ONH to the macula. Fully automated quantification of these structures will be developed. 4. Evaluate advanced OCT technologies in clinical studies. The utility of functional and structural OCT in glaucoma will be evaluated in a longitudinal observational study of 150 glaucoma and healthy subjects. The effect of IOP-lowering surgery on blood flow will be studied in 40 subjects. Retinal blood flow, ONH circulation, optic disc rim volume, peripapillary nerve fiber layer volume, and macular ganglion cell complex volume are all pieces of the same glaucoma puzzle. This project will develop novel imaging methods that allow us to look at the whole picture using one tool - ultrahigh-speed OCT.