屈光参差性弱视儿童运动视觉功能的MRI研究

摘要

目的:利用血氧水平依赖性功能磁共振成像(BOLD-fMRI)技术研究屈光参差性弱视儿童双眼间运动视觉功能相关大脑皮层功能改变.方法:系列病例研究.收集2017年6-12月在天津市眼科医院确诊为屈光参差性弱视患儿25例(25眼)作为弱视组,年龄6～15岁,招募健康志愿者25例(25眼)作为正常对照组,年龄6～14岁,采用水平左向、右向移动垂直正弦光栅,1.5T磁共振成像系统扫描图像获取数据.受试者完成视觉任务及数据采集后,应用SPM5软件进行预处理,数据比较采用t检验.结果:正常对照组激活最明显的区域为中颞区、Brodmann 19区和37区.弱视组弱视眼较正常对照组在中颞区、Brodmann 19区、37区减少显著,额叶有较大范围激活.弱视组对侧眼Brodmann 37区、18区为激活低于正常对照组的主要脑区.弱视组弱视眼和对侧眼比较,MT区和Brodmann 19区、18区为主要激活体积及强度减少区,额中回为主要激活及强度增强区.结论:屈光参差性弱视儿童弱视眼视觉运动功能皮层BOLD-fMRI信号异常表现为脑皮层激活区体积和强度较正常儿童明显下降,且对侧非弱视眼激活脑区亦存在异常.单眼视觉运动刺激时,弱视眼有更多的脑区参与反应.%Objective: To detect the pathogenetic mechanism of motion-sensitive cortical deficit in response to motion stimuli in children with anisometropic amblyopia using a blood oxygenation level-dependent functional magnetic resonance imaging technique (BOLD-fMRI). Methods: This was a case series study. Patients were collected from June to December 2017 at Tianjin Eye Hospital. Twenty-five patients who were diagnosed with anisometropic amblyopia as amblyopia group and twenty-five normal volunteers were examined as control group. A BOLD-fMRI technique on a 1.5T MRI and a horizontally moving sinusoidalgrating block design were used for task conditions. All data were processed with SPM5 software, were analyzed by t test. Results: Significant fMRI activation and comparable right and left eye activation were found in the middle temporal area (MT), and Brodmann areas 19 and 37, in all control subjects; Lesser cortical activation in area MT and Brodmann areas 37, 19, and greater activation in the frontal gyrus of the lazy eye group were detected compared to the control group. Lesser cortical activation in Brodmann area 37, 18 of the contralateral eye of the amblyopic group was detected compared to the control group. Lesser cortical activation in area MT and Brodmann areas 19, 18, and greater activation in the frontal lobes of the anisometropic amblyopic eyes were detected compared to the contralateral eyes. Conclusions: The spatial extent and intensity of the visual cortex activation in the visual cortex decreases in the amblyopic eye compared to the normal control. Decreased cortical activation in the fellow eye is prevalent. A greater visual cortex area is activated when stimulating the amblyopic eye.