Qi Wenxu, Gao Song, Liu Caixia, Lan Gongyu, Yang Xue, Guo Qiyong
Department of Radiology, Shengjing Hospital, China Medical University, Shenyang, 110004, People's Republic of China.
Morphology Teaching and Reasearch Section, Liaoning Vocational College of Medcine, Shenyang, 110100, People's Republic of China.
BMC Med Imaging. 2017 Aug 22;17(1):50. doi: 10.1186/s12880-017-0205-9.
The purpose of this study was to investigate the anisotropic features of fetal pig cerebral white matter (WM) development by magnetic resonance diffusion tensor imaging, and to evaluate the developmental status of cerebral WM in different anatomical sites at different times.
Fetal pigs were divided into three groups according to gestational age: E69 (n = 8), E85 (n = 11), and E114 (n = 6). All pigs were subjected to conventional magnetic resonance imaging (MRI) and diffusion tensor imaging using a GE Signa 3.0 T MRI system (GE Healthcare, Sunnyvale, CA, USA). Fractional anisotropy (FA) was measured in deep WM structures and peripheral WM regions. After the MRI scans,the animals were sacrificed and pathology sections were prepared for hematoxylin & eosin (HE) staining and luxol fast blue (LFB) staining. Data were statistically analyzed with SPSS version 16.0 (SPSS, Chicago, IL, USA). A P-value < 0.05 was considered statistically significant. Mean FA values for each subject region of interest (ROI), and deep and peripheral WM at different gestational ages were calculated, respectively, and were plotted against gestational age with linear correlation statistical analyses. The differences of data were analyzed with univariate ANOVA analyses.
There were no significant differences in FAs between the right and left hemispheres. Differences were observed between peripheral WM and deep WM in fetal brains. A significant FA growth with increased gestational age was found when comparing E85 group and E114 group. There was no difference in the FA value of deep WM between the E69 group and E85 group. The HE staining and LFB staining of fetal cerebral WM showed that the development from the E69 group to the E85 group, and the E85 group to the E114 group corresponded with myelin gliosis and myelination, respectively.
FA values can be used to quantify anisotropy of the different cerebral WM areas. FA values did not change significantly between 1/2 way and 3/4 of the way through gestation but was then increased dramatically at term, which could be explained by myelin gliosis and myelination ,respectively.
本研究旨在通过磁共振扩散张量成像研究胎猪脑白质（WM）发育的各向异性特征，并评估不同解剖部位脑白质在不同时期的发育状况。
根据胎龄将胎猪分为三组：E69（n = 8）、E85（n = 11）和E114（n = 6）。所有猪均使用GE Signa 3.0 T MRI系统（美国加利福尼亚州森尼韦尔市GE医疗集团）进行常规磁共振成像（MRI）和扩散张量成像。在深部白质结构和外周白质区域测量分数各向异性（FA）。MRI扫描后，处死动物并制备病理切片进行苏木精-伊红（HE）染色和髓鞘碱性蛋白（LFB）染色。数据采用SPSS 16.0版（美国伊利诺伊州芝加哥市SPSS公司）进行统计分析。P值<0.05被认为具有统计学意义。分别计算不同胎龄时每个感兴趣区域（ROI）以及深部和外周白质的平均FA值，并通过线性相关统计分析将其与胎龄进行绘制。数据差异采用单因素方差分析进行分析。
左右半球之间的FA值无显著差异。在胎脑中观察到外周白质和深部白质之间存在差异。比较E85组和E114组时发现，随着胎龄增加FA显著增长。E69组和E85组之间深部白质的FA值无差异。胎脑白质的HE染色和LFB染色显示，从E69组到E85组的发育以及从E85组到E114组的发育分别与髓鞘形成和髓鞘化相对应。
FA值可用于量化不同脑白质区域的各向异性。在妊娠中期到妊娠晚期的3/4期间FA值无显著变化，但在足月时显著增加，这分别可以用髓鞘形成和髓鞘化来解释。
