中文摘要：

目的探讨原发性开角型青光眼（POAG）患者视放射改变及其与疾病严重程度的相关性。方法收集2011年1月至2013年6月北京同仁医院青光眼门诊24例POAG患者及20名性别年龄匹配的正常受试者的眼底镜检查、视野检查、眼压测量以及扩散张量成像资料。根据Hodapp—Anderson．Parrish（HAP）分期系统将POAG患者双眼进行分期，以双侧HAP分期之和作为评估疾病严重程度的指标。通过纤维束示踪方法提取受试者双侧视放射的白质，比较两组间的部分各向异性指数（FA）、平均扩散率（MD）、垂直扩散率（RD）和轴向扩散率（AD）的差异，并分析DTI指标与疾病严重程度的相关性。结果POAG组左侧视放射的FA值低于对照组（t=一3．299，P=0．002），RD高于对照组（t=2．365，P=0．018）；AD值低于对照组（t=-2．485，P=0．013），MD值差异无统计学意义（t=0．719，P=0．454）。POAG组右侧视放射的FA值低于对照组（t=-2．900，P=0．006），RD高于对照组（t=2．533，P=0．016）；AD值低于对照组（t=-2．040，P=0．048）；MD值差异无统计学意义（t=1．381，P=0．176）。Spearman秩相关检验结果显示POAG患者双侧视放射的平均FA值与POAG疾病严重程度呈负相关（r=-0．643，P=0．001），双侧平均RD值与疾病严重程度呈正相关（r=0．570，P=0．004），双侧平均MD值与疾病严重程度呈正相关（r=0．448，P=0．028），双侧平均AD值与疾病严重程度无相关性（r=0．033，P=0．878）。结论POAG患者视放射的FA值及AD值降低，RD值升高，提示POAG患者视放射的神经纤维存在髓鞘的损伤，而且POAG患者的视放射的FA值、RD值以及MD值与疾病进展的严重程度相关。

英文摘要：

Objective To study the alteration of the optic radiations in patients with primary openangle glaucoma （POAG） by diffusion tensor imaging （DTI） and tractography, and to reveal the correlation between the DTI derived parameters and the severity of the disease. Methods A total of 24 patients with POAG and 20 age- and gender-matched healthy controls were enrolled in this study from January 2011 to June 2013. All subjects underwent ophthalmoscopy, standard automatic perimetry, intraocular pressure measurement and MRI scanning. All the eyes of POAG patients were evaluated by Hodapp-Anderson-Parrish （HAP） system. Then the stages of bilateral eyes were added together to evaluate the disease severity. Tractography was used to measure the fractional anisotropy （ FA）, mean diffusivity （ MD）, radial diffusivity （RD） and axial diffusivity （AD） of the optic radiations of these subjects. The results of the two groups were compared. Partial correlation was then used to reveal the correlation between these derived DTI parameters and the severity of POAG. Results Compared with health controls, POAG patients showed significant decreased FA （t = -3. 299,P =0. 002） and AD （t = -2. 485,P =0. 013）, increased RD （t = 2. 365 ,P = 0. 018） in optic radiation. The alteration of MD was not significant （t = 0. 719, P = 0. 454）. Mean FA values of the optic radiations were negatively correlated with POAG stages （ r = - 0. 643, P = 0. 001 ）, while mean RD values （ r = 0. 570, P = 0. 004） and mean MD values （ r = 0. 448, P = 0. 028 ） were positively correlated with POAG stages. No correlation between AD values and severity of POAG was found. Conclusion In the optic radiations of POAG patients, the FA values and AD values decrease, while RD values increase, indicating the fiber integrity changes. The alterations of FA, RD and MD are correlated with disease severity.