DTI和T_(1)WI测值法在早产儿脑发育评估中的应用价值

Application of diffusion tensor imaging and T_(1)WI value measurement on white matter development in preterm infants

目的:探讨磁共振扩散张量成像(DTI)和T_(1)WI测值法在早产儿脑发育评估中的应用价值。方法:将32例早产儿根据分娩孕周分为早期早产儿组(出生胎龄≤32周,19例)和中晚期早产儿组(出生胎龄>32周,13例),均进行DTI检查,测量感兴趣区(ROI)的各向异性分数(FA)值和表观扩散系数(ADC)值。ROI包括胼胝体压部和膝部、双侧脑室后角、双侧内囊后肢、双侧半卵圆中心。T_(1)WI在相同部位上测量信号值。统计分析两组FA值和ADC值的差异,评估胎龄对早产儿脑白质发育情况的影响。结果:早期早产儿组与中晚期早产儿组胼胝体膝部的FA值分别为(0.55±0.06)、(0.60±0.04),胼胝体压部的FA值分别为(0.65±0.05)、(0.71±0.07);早期早产儿组与中晚期早产儿组胼胝体膝部的ADC值分别为(1.30±0.12)、(1.19±0.10)×10^(-3) mm^(2)/s,胼胝体压部的ADC值分别为(1.21±0.14)、(1.09±0.13)×10^(-3) mm^(2)/s。与中晚期早产儿组相比,早期早产儿组胼胝体膝部、胼胝体压部的FA值降低,ADC值升高,且差异均有统计学意义(P值均<0.05)。两组间同部位ROI的T_(1)WI测值差异均无统计学意义(P值均>0.05)。结论:DTI的FA值和ADC值、T_(1)WI测值均可反映早产儿脑白质发育情况,以FA值最为敏感,早期早产儿较中晚期早产儿的脑白质髓鞘化相对滞后。

Objective:To explore the application of diffusion tensor imaging(DTI)and T_(1)WI value measurement on white matter development in preterm infants.Methods:According to Gestational age(GA),32 preterm infants were divided into two groups:early preterm infant group(GA≤32 weeks,n=19)and mid-late preterm infant group(GA>32 weeks,n=13).Diffusion tensor imaging and T_(1)WI were performed.The fractional anisotropy(FA),apparent diffusion coefficient(ADC)and T_(1)WI signal value of rregion of interest(ROI)were measured.ROI were set on the knees of the the corpus callosum,the splenium of the corpus callosum,bilateral peri-ventricles posterior horns,the posterior limbs of the bilateral internal capsule,and bilateral centrum semi-ovale.Differences of FA and ADC value between two groups were analyzed to evaluate the effect of GA week on brain white matter development in premature infants.Results:Compared with mid-late preterm infant group,the FA value of corpus callosum knee and corpus callosum in the early preterm infant group was lower,and ADC value was higher.The difference between the two groups had statistical significance(P<0.05).There was no statistical difference in T_(1)WI signal value between the two groups of all ROI(P>0.05).Conclusion:DTI method and T_(1)WI signal value measurements can monitor the development of white matter in premature infants,especially FA value is of the most sensitive.Compared with the mid-late preterm infants,white matter myelinations in early preterm infants are relatively lagging behind.