Functional and Structural Optical Coherence Tomography for Glaucoma

描述（由申请人提供）：青光眼是致盲的主要原因。青光眼的早期诊断和密切监测是重要的，因为它的发病是隐匿的，损害是不可逆的。在过去的20年里，光学相干断层扫描（OCT）等先进的成像技术被用于改善青光眼的客观评价。OCT具有比其他眼后成像方式更高的轴向空间分辨率，在测量青光眼神经结构损伤方面具有较好的诊断准确性和可重复性。然而，单独测量结构，与任何成像方式，对早期青光眼的检测灵敏度有限，并且与视野（VF）损失只有中等程度的相关性。利用高速OCT系统，我们开发了成像和测量视神经头（ONH）和视网膜血流的新方法。初步结果显示，与OCT或其他成像方式测量的任何神经结构相比，VF损失与视网膜血流量的相关性更高。因此，该项目的目标是通过使用超高速（70-100 kHz） OCT技术进一步开发新型功能OCT测量来改善青光眼的诊断和预后评估。具体目标是：1。改进多普勒OCT测量视网膜血流。多循环扫描乳头周围视网膜动脉和静脉测量视网膜总血流在2秒。使用更快的OCT系统将允许自动测量，并提高再现性。2. 发展ONH的定量OCT血管造影。三维（3D） OCT血管造影已经成为现实（3秒内扫描3x3毫米）通过一种新的分谱振幅去相关算法。初步结果显示早期青光眼患者ONH微循环明显丧失。计划在血管造影、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。通过注册几次体积扫描，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。这些结构的全自动量化将得到发展。4. 评估临床研究中的先进OCT技术。对150名青光眼患者和健康受试者进行纵向观察研究，以评估功能和结构OCT在青光眼中的应用。将对40例患者进行降眼压手术对血流的影响进行研究。视网膜血流、ONH循环、视盘边缘体积、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青光眼的拼图。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.