原发性开角型青光眼V1区皮层功能变化的功能MRI研究

目的 利用fMRI视网膜皮层映射技术研究原发性开角型青光眼(POAG)患者V1区皮层功能变化.方法 选取15例POAG患者及15名正常志愿者,利用视网膜皮层映射分区刺激和圆形黑白翻转棋盘格刺激采集fMRI数据.采用配对样本t检验比较POAG患者患侧眼与健侧眼V1区的fMRI反应、独立样本t检验比较健侧眼与匹配的正常人眼V1区的fMRI反应和激活.POAG患者患侧眼和健侧眼单独刺激时的V1皮层功能差异与视功能差异做线性相关分析.结果 (1)患侧眼接受刺激时V1区fMRI反应较健侧眼弱(t=4.757,P<0.01),患侧眼和健侧眼fMRI反应分别为(1.24±0.72)%、(2.18±0.93)%.患侧眼、健侧眼分别与其年龄、性别、眼侧别相匹配的正常人眼V1区fMRI反应进行比较:患侧眼较正常人眼反应弱(t=-3.011,P<0.01),患侧眼和匹配眼fMRI反应分别为(1.24±0.72)%、(2.01±0.65)%;健侧眼和匹配眼反应差异无统计学意义(t=0.742,P＞0.05),健侧眼和匹配眼分别为(2.18±0.93)%、(1.95±0.75)%.(2)患侧眼与健侧眼单独刺激的V1皮层功能差异与视功能差异存在线性负相关(r=-0.887,P<0.01).(3)患者的健侧眼与其年龄、性别、眼侧别相匹配的正常人眼比较,患者健侧眼V1激活较正常人眼小(t=-3.801,P<0.01),健侧眼和匹配眼V1激活面积指数分别为0.72±0.12、0.85±0.09.结论 青光眼存在皮层功能损害,而且青光眼皮层功能的损害与视觉功能的损害存在相关一致性;基于fMRI视网膜皮层映射分区的定位、定量测量是一种对青光眼视觉皮层功能变化临床随访、评估测量的有用方法,也是活体人青光眼视觉通路跨突触退变研究的潜在有用工具.

Functional alterations of V1 cortex in patients with primary open angle glaucoma using functional MRI retinotopic mapping

Objective To evaluate the functional changes of visual cortex (V1) in patients with primary open angle glaucoma (POAG) by fMRI retinotopic mapping technology. Methods Fifteen POAG patients and 15 healthy volunteers underwent stimulations with fMRI retinotopic mapping stimulus and contrast-reversing checkerboard patterns stimulus on a Siemens Trio 3.0 T MRI whole-body scanner for functional data collection. Comparisons of V1 fMRI responses between the glaucomatous eyes and the healthy eyes of the patients were carried out using paired samples t-test, while independent samples t-test was used to compare V1 fMRI responses and activations between the healthy eyes of patients and the age-, gender- and side- matched eyes of normal people. Differences of V1 cortical functions and visual functions were analyzed by linear correlation analysis when the glaucomatous and the healthy eyes were simulated individually. Results (1) V1 fMRI responses of the individually stimulated glaucomatous eyes[(1.24±0.72)%]were weaker than those of the healthy eyes[(2.18±0.93)%](t=4.757,P<0.01). Comparisons of V1 fMRI responses between the glaucomatous eyes and matched eyes of normal people, as well as between the healthy eyes of patients and the matched eyes of normal people, were performed respectively: the responses in the glaucomatous eyes[(1.24±0.72)%]were weaker than those in the matched eyes of normal people[(2.01±0.65)%](t=-3.011,P<0.01). There was no statistical difference of the responses between the healthy eyes from patients[(2.18±0.93)%]and the matched eyes of normal people[(1.95±0.75)%](t=0.742,P＞0.05). (2) Differences of V1 cortical functions were negatively correlated with those of visual functions in the individually stimulated glaucomatous and healthy eyes (r=-0.887, P<0.01). (3) The activated area indexes of V1 cortexes in the healthy eyes from patients (0.72±0.12) were lower than those in the matched eyes of normal people (0.85±0.09) (t=-3.801, P<0.01). Conclusion Cortical function impairment was in accordance with visual function impairment in glaucoma. Located and quantified measurement with fMRI retinotopic mapping was a useful method for clinical follow-up and evaluation of functional alteration of glaucomatous visual cortex, and a potentially useful means of studying trans-synaptic degeneration of visual pathways of in vivo glaucoma.