Brain MRI of Human Glaucoma

摘要：人类青光眼的脑MRI表现 原发性开角型青光眼(POAG)是导致失明的主要原因，影响着400万美国人。 这种疾病始于周边视力的丧失，然后是中央视力。同时眼压升高 被认为是导致视网膜神经节细胞死亡的关键致病机制，许多青光眼患者 尽管成功地进行了降低眼压的治疗，但仍继续失明。在这里，我们追求一部小说 认为青光眼时也会出现脑部病变的假说，有助于疾病的发病机制 和进步。 这一假设是基于我们初步的功能磁共振数据显示，轻度到中度的POAG患者 在视觉皮质中有功能的重新映射。这些初步的fMRI数据还显示，变化不仅限于 周围视野到中央视野的功能，但也是疾病严重程度的功能。此外，这些功能 变化与大脑视觉通路中的灰质和白质退化有结构性关联。更多 青光眼的有效治疗可能需要同时针对眼睛和大脑的综合策略。 我们的发现与先前的组织学证据一致，即大脑视觉同时存在神经变性。 青光眼的通路。事实上，一些研究甚至表明，大脑视觉通路中的结构性损伤 在视网膜神经节细胞纤维丢失之前，表明神经退行性变在这种失明中起作用 无序。先前的几项仅刺激中央视野的功能磁共振研究报告称，总体上减少了 青光眼患者视皮层的刺激诱发活动。然而，目前还不清楚在多大程度上 青光眼患者视皮质的外周和中枢视功能改变及其功能 重新定位与疾病的进展有关。 根据我们的初步数据，我们假设青光眼导致视觉的功能重新映射 功能磁共振成像非侵入性检测到皮质，更多的功能和结构异常的神经变性 来自MRI的研究预测，在青光眼相同临床阶段的患者中，视野丧失的进展更快。这个 本研究的第一个目的是确定青光眼患者在不同时期的脑功能和结构变化。 横断面设计中的严重程度阶段。第二个目标是阐明大脑的变化是如何起作用的。 在纵向设计中对临床青光眼进展的风险进行亚分层。翻译方面的影响将是 通过将MRI结果与临床眼科检查(包括眼压、视野)进行比较而增加 视野检查、视网膜神经纤维层厚度和扩张眼底照相。

Abstract: Brain MRI of human glaucoma Primary open angle glaucoma (POAG) is a leading cause of blindness, affecting 4 million Americans. The disease starts with loss of peripheral vision followed by central vision. While elevated intraocular pressure is thought to be a critical pathogenic mechanism causing retinal ganglion cell death, many glaucoma patients continue to lose vision despite successful treatment to lower intraocular pressure. Here, we pursue a novel hypothesis that pathological changes to the brain also occur in glaucoma, contributing to disease pathogenesis and progression. This hypothesis is based on our preliminary fMRI data showing that mild to moderate POAG patients have functional remapping in the visual cortex. These preliminary fMRI data also show changes vary not only as a function of peripheral to central visual field but also as a function of disease severity. Further, these functional changes have structural correlates of gray- and white-matter degeneration in the brain visual pathways. More effective treatment for glaucoma may require comprehensive strategies that target both the eye and the brain. Our findings agree with prior histological evidence of concurrent neurodegeneration in the brain visual pathway in glaucoma. In fact, some studies even show that structural damage in the brain visual pathway precedes the loss of retinal ganglion cell fibers, suggesting neurodegeneration plays a role in this blinding disorder. A few prior fMRI studies, stimulating only the central visual field, have reported overall reduced stimulus-evoked activities in the visual cortex in glaucoma patients. However, it remains unknown to what extent the peripheral and central visual function in the visual cortex is altered in glaucoma and how this functional remapping relates to the progression of the disease. Based on our preliminary data, we hypothesize that glaucoma leads to functional remapping of the visual cortex as detected non-invasively by fMRI, and that more abnormal functional and structural neurodegeneration from MRI predicts faster progression of visual field loss in patients at the same clinical stage of glaucoma. The first aim of this study will determine functional and structural changes in the brain of glaucoma patients at different stages of severity in a cross-sectional design. The second aim will elucidate how changes in the brain can help to sub-stratify risk of clinical glaucoma progression in a longitudinal design. The translational impact will be increased by comparing MRI findings with clinical eye exams that include intraocular pressure, visual field perimetry, retinal nerve fiber layer thickness, and dilated fundus photography.