新生儿大脑纤维束观察值及其对侧化的影响

目的 探讨新生儿纤维束追踪参数改变对纤维束追踪稳定性及纤维侧化发育的影响。 方法 获取40例36.6~42.1周(中位数为40周)足月新生儿多球壳弥散张量数据(HARDI),使用MRtrix3软件,采用多感兴趣区(ROIs)协议追踪皮质脊髓束(CST)、扣带纤维(CGC)、胼胝体大钳(Fmajor)、胼胝体小钳(Fminor)、下纵束(ILF)、钩束(UNC)、额枕下束(IFO)等脑内主要纤维束,通过双因素重复方差分析及计算期望值的方法分析不同终止值域及最大转角对纤维束体积及稳定性的影响,采用裂区设计分析不同参数对侧化发育的影响。 结果 当最大转角为45°时纤维体积明显减少,当纤维终止值域为0.02时,纤维追踪的评分者内信度及评分者间信度减低且一致性离散度增大;不同的纤维追踪参数设定对双侧不同纤维的侧化存在影响,双侧皮质脊髓束、扣带纤维及钩束的侧化发育均有统计学意义(P<0.001,P=0.017,P=0.024)。在皮质脊髓束、扣带束的分数各向异性(FA)平均值测量中,终止值域和最大转角对双侧皮质脊髓束、扣带束的侧化影响的主效应均具有统计学意义。 结论 采用合适的追踪参数设定能够提高纤维追踪的稳定性,有助于分析新生儿大脑发育的普遍规律。

Observation value of neonatal cerebral fiber bundle and its effect on lateralization

Objective To explore the effect of the changes of parameters of neonatal cerebral fiber bundle on the reproducibility and lateralization. Methods High angular resolution diffusion imaging(HARDI)data were obtained in 40 term infants born between 36.6 and 42.1 weeks(median 40 weeks). Multiple regions of interest(ROIs)protocol were used to describe the main brain tracks, such as cortico-spinal tract(CST), cingulum cingulate(CGC), forceps major(Fmajor)and frontal projection(Fminor)of corpus callosum, inferior longitudinal fasciculus(ILF), uncinate fasciculus(UNC)and inferior fronto-occipital fasciculus(IFO)by MRtrix3 software. Different cutoff values and angles were analyzed to evaluate the volume changes and reproducibility of tracks, and the effect on lateralization was analyzed with splicing design variance analysis. Results The volume of tracts significantly reduced if the angle was 45, while the inter-rater and intra-rater variability reduced with the consistency dispersion increased if the cutoff value was 0.02. The changes of tractography parameters affected the results of lateralization analysis. The bilateral CST, CGC and UNC showed significant lateralization. The FA values of corticospinal tract and cingulate tract showed statistically significant lateralization, which were mainly affected by changes of the cutoff and angle. Conclusion Optimal parameters of tractography will improve the reproducibility of results of fiber tracking, which is expected to be helpful to describe development of newborn white matter tracts.