FA值在监测评价HIE患儿脑髓鞘发育中的作用

FA VALUES IN EVALUATING MYELINATION OF NEONATAL HYPOXIC-ISCHEMIC ENCEPHALOPATHY

目的应用磁共振弥散张量成像（DTI）定量测定FA值，而各向异性弥散可反映脑的微结构信息，探讨DTI在随访复查婴幼儿期缺氧缺血性脑病（HIE）中的应用价值，揭示HIE影响患儿脑髓鞘发育及预后状况的特征。材料与方法追踪复查45例6-30个月婴幼儿期足月HIE患儿，依据新生儿期初查时临床表现分为轻度、中度和重度3组进行DTI检查，测定3组患儿相同感兴趣区的分数各向异性（FA）值。结果FA值在胼胝体压部、内囊后肢、放射冠、额叶白质、顶叶白质的组间差异均有统计学意义，FA值随病情加重而减低。在豆状核组间差异无统计学意义。结论磁共振弥散张量成像的FA值，在HIE复查中可定量反映新生儿期不同轻重程度HIE患儿脑损伤对不同时期脑白质髓鞘发育的影响度，较常规磁共振成像评价更为准确、客观、敏感；初步提出作为新生儿缺氧缺血性脑病的病情评估和预后预测的标志性指标。

Objective To determine the use of quantitative diffusion anisotropy values as an objective means of detecting infants suffering from hypoxic-ischemic encephalopathy （HIE） in fullterm neonatal period, and to evaluate the follow-up value of DTI on full-term HIE and the effect of HIE on myelination. Materials and Methods Quantitative diffusion tensor MR images from 45 infants who had been clinically diagnosed as HIE before, including 20 mild cases, 16 moderate cases, 9 severe cases. Fractional anisotropy （FA） values were calculated in predefined regions of the three groups. A one-way ANOVA（analysis of varriance） was performed to compare FA values among the groups for each region. Results FA values of the three groups were significantly different in regions of intresting （ROIs） ： splenium of corpus callosum, posterior limb of internal capsule, corona radiate, front white matter, parietal white matter, and FA values decreased in line with the ascending degree of HIE. FA values of the three groups were not significantly different in putamina nuclei. Conclusion Quantitative diffusion tensor of anisotropy values can improve conspicuity better than conventional MRI images and provide an objective measure of hypoxic-ischemic injury on myelina- tion of white matters. Calculation of anisotropy values may provide a valuable marker index for the severity of hypoxic-ischemic injury and a predictor of prognosis.