Magnetic Resonance Imaging of Glaucoma

青光眼的磁共振成像

• 批准号: 9128017
• 负责人: Timothy Q. Duong
• 金额: $ 5.2万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2017-01-06
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9128017
• 关键词: Affect; Age; Age-Months; Air; Anatomy; Area; Axon; Biological Markers; Blindness; Blood Vessels; Blood flow; Carbon Dioxide; Choroid; Chronic; Control Animal; Data; Development; Diabetic Retinopathy; Disease; Dorzolamide; Early Diagnosis; Early treatment; Equilibrium; Evaluation; Eye; Foundations; Functional Imaging; Functional Magnetic Resonance Imaging; Future; Genetic; Glaucoma; Health; Histology; Human; Hypercapnia; Hyperoxia; Hypoxia; Image; Imaging Techniques; Imaging technology; Injury; Ischemia; Knowledge; Laboratories; Magnetic Resonance Imaging; Measurement; Mediating; Modeling; Monitor; Morphologic artifacts; Mus; Nerve Fibers; Optic Disk; Optic Nerve; Outcome; Pathogenesis; Patients; Phase; Physiologic Intraocular Pressure; Physiological; Predisposition; Production; Research; Resolution; Retina; Retinal; Retinal Degeneration; Retinal Diseases; Retinal Ganglion Cells; Risk; Scheme; Specificity; Staging; Stimulus; Therapeutic Intervention; Thick; Time; Tissues; Treatment Protocols; Visual impairment; animal data; aqueous; base; blood oxygen level dependent; blood oxygenation level dependent response; cell injury; clinically relevant; clinically significant; data acquisition; density; efficacy testing; ganglion cell; hemodynamics; improved; insight; male; non-invasive imaging; novel; prevent; relating to nervous system; research study; response; retinal nerve fiber layer; spatiotemporal; treatment effect; visual stimulus

DESCRIPTION (provided by applicant): Glaucoma, a leading cause of irreversible blindness in the world, is characterized by progressive degeneration of the retinal ganglion cells (RGCs), the retinal nerve fiber layer, and the optic nerve. Glaucoma is often associated with elevated intraocular pressure (IOP), and because the increased IOP exerts a compressing force on the blood vessels in the eye, it has long been hypothesized that the RGC damage is caused by mild, but chronic, reduction of basal blood flow and/or blood-flow dysregulation. For many patients, by the time glaucoma is detected in examinations or patients notice vision loss, more than half of the RGCs have already degenerated. The eventual outcome is often blindness. Thus, non-invasive imaging technologies capable of detecting depth-resolved blood flow, oxygenation, and stimulus-evoked hemodynamic changes to evaluate blood flow reduction and dysregulation in the retina and the optic nerve head could enable objective early detection, longitudinal disease staging, and monitoring of therapeutic interventions. Although optically based imaging techniques provide high spatial resolution, they are depth limited which precludes quantitative resolution of retinal, choroidal, and optic nerve blood flow. Our laboratory pioneered the application of multimodal MRI to image high-resolution lamina-specific anatomy, blood flow, oxygenation, and function of the retina without depth limitation. Here we propose: i) to develop a multimodal MRI approach to markedly improve contrast and spatial resolution (35x35x300 �m) without MRI susceptibility artifact by using a 3D balanced Steady State Free Precession (bSSFP) data acquisition scheme, and ii) to apply this approach in an established genetic (DBA/2J) mouse glaucoma model to determine whether MRI can detect glaucomatous changes in early stage and examine a plausible mechanism of glaucoma pathogenesis. We hypothesize that: 1) MRI can provide high resolution, depth-resolved, laminar- specific anatomical, blood flow, and functional images free of susceptibility artifacts; and 2) the pathogenesis of glaucoma is mediated by reduced blood flow and/or blood-flow dysregulation in the early stage, resulting in eventual loss of RGCs by ischemic hypoxia, and, if this is the cause, hyperoxia treatment should halt glaucomatous damage.

描述（申请人提供）：青光眼是世界上导致不可逆失明的主要原因，其特征是视网膜神经节细胞（RGC）、视网膜神经纤维层进行性退化，并且青光眼通常与视神经升高有关。眼内压（IOP），并且由于增加的IOP对眼睛内的血管产生压迫力，因此长期以来人们一直探索RGC损伤是由轻度、但对于许多患者来说，当检查发现青光眼或发现视力丧失时，一半以上的视网膜神经节细胞已经退化，最终的结果往往是失明。因此，能够检测深度分辨血流、氧合和刺激引起的血流动力学变化的非侵入性成像技术，以评估视网膜和视神经头的血流减少和失调，可以实现客观的早期检测、纵向虽然基于光学的成像技术提供了高空间分辨率，但它们的深度有限，这妨碍了我们实验室的视网膜、脉络膜和视神经血流的定量分辨率。 率先应用多模态 MRI 对视网膜的高分辨率层状解剖结构、血流、氧合和功能进行成像，不受深度限制。在此我们建议：i) 开发一种多模态 MRI 方法，以显着提高对比度和空间分辨率。 35x35x300 µm)，通过使用 3D 平衡稳态自由进动 (bSSFP) 数据采集方案，没有 MRI 磁化率伪影，以及 ii) 将此方法应用于我们建立了 (DBA/2J) 小鼠青光眼模型，以确定 MRI 是否可以检测早期青光眼变化并检查青光眼发病机制的合理机制。我们发现：1) MRI 可以提供高分辨率、深度分辨、层状特异性解剖学信息。 、血流和功能图像，无磁敏感伪影；2) 青光眼的发病机制是由血流减少和/或血流失调介导的；早期阶段，最终因缺血性缺氧而导致 RGC 损失，如果这是原因， 高氧治疗应该可以阻止青光眼损伤。