屈光参差性弱视视放射及胼胝体的扩散张量成像研究

目的利用磁共振扩散张量成像技术（DTI）检测屈光参差性弱视儿童视觉通路中视放射及胼胝体的发育情况，从而探讨其发病机制。方法采集14例左眼屈光参差性弱视儿童和30例正常对照儿童DTI数据，分别测定弱视组和对照组两侧视放射及胼胝体的各向异性分数（FA）值、表观扩散系数（ADC）值，并进行比较分析。结果左眼弱视组和正常对照组均表现为左侧视放射的FA值高于右侧（P〈0．05），ADC值低于右侧（P〈0．05）。组间分析，左眼弱视组两侧视放射的FA值均低于正常对照组（P〈0．05），ADC值均高于正常对照组（P〈0．05），胼胝体压部ADC值高于正常对照组（P〈0．05）。结论屈光参差性弱视儿童的视放射及胼胝体压部的FA和ADC值与正常对照组比较差异有统计学意义，提示其神经纤维存在一定程度的发育不良，可能是屈光参差性弱视儿童单眼及双眼视功能低下的机制之一。

Study on the optic radiation and corpus callosum in children with anisometropic Amblyopia by diffusion tensor imaging

Objective To evaluate the development of optic radiations(ORs) and corpus callosum in children with anisometropic amblyopia by using diffusion tensor imaging(DTI),and to explore the underlying mechanism of pathogenesis of amblyopia.Methods Fourteen children with anisometropic amblyopia(all left eyes) and 30 normally sighted children underwent DTI scanning.The fractional anisotropy(FA) values and the apparent diffusion coefficient(ADC) values of ORs and corpus callosum were measured.Comparisons of FA values and ADC values were made both within the groups(Left to Right comparison) and between the two groups.Results In both groups,the FA values of left ORs were higher than those of right ORs and the ADC values of left ORs were lower than those of right ORs(P<0.05).The FA values of ORs in children with amblyopia were lower than those of ORs in children with normal sights(P<0.05),while the ADC values of ORs were higher(P<0.05).And the ADC values of splenium corporis callosi in children with amblyopia were higher than those of splenium corporis callosi in children with normal sights(P<0.05).Conclusion The difference between the anisometropic amblyopia and the normal controls reflect the underdevelopment of ORs and splenium corporis callosi in children with anisometropic amblyopia.