屈光不正性弱视儿童皮层功能与弱视程度关系的功能磁共振研究

目的利用血氧水平依赖性功能性磁共振成像（blood oxygenation dependent level functional MRI,BOLD-fMRI）技术研究儿童屈光不正性弱视对不同级别大脑视觉皮层功能的影响,比较即时矫正屈光不正后视皮层的激活特点,分析皮层激活改变与弱视程度之间的关系。方法以SIEMENS AVANTO1.5 T磁共振成像系统采集18例屈光不正性弱视儿童及18例正常视力儿童的枕叶视皮层感兴趣区BOLD-fMRI数据,图像处理及分析为本核磁扫描仪自带软件。比较弱视组与对照组及弱视组即时屈光矫正前后皮层激活强度及范围的不同,分析其改变特点及机制。对患儿弱视程度分级,分析其与皮层激活改变的关系。结果弱视组皮层神经元的反应水平及激活范围均明显小于对照组;弱视组即时矫正屈光不正后皮层活动水平有所增高,激活范围增大,同时在楔叶、舌回等次级视皮层等有额外反应。同时皮层激活范围与弱视程度不成线性相关。结论屈光不正性弱视各级视觉皮层均发生了激活范围的改变,弱视眼矫正屈光不正后皮层激活范围明显增大,提示尽早矫正视力对改善弱视皮层损害有帮助,但这种皮层激活范围的改变与弱视程度并不呈线性相关。

Bold-functional MRI evaluation of the relationship between the level of amblyopia and the functional of the visual cortex in child ametropic amblyopia

Objective To assess the influence of ametropic amblyopia on different level of visual cortex and compare the features of the cortex activations before and after ametropia correction on ametropic amblyopias with blood oxygenation dependent level functional MRI techniques(bold-fMRI).Methods Functional evaluations were performed on a 1.5 Tesla MR I device with the experimental group before and after ametropia correction on 18 ametropic amblyopes and 18 normal subjects in control group.The stimulating apparatus...