正常发育过程中人类胎儿基板层和中间带在磁共振和弥散张量成像上的改变。
Alteration of human fetal subplate layer and intermediate zone during normal development on MR and diffusion tensor imaging.
机构信息
Diagnostic Imaging, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada.
出版信息
AJNR Am J Neuroradiol. 2010 Jun;31(6):1091-9. doi: 10.3174/ajnr.A1985. Epub 2010 Jan 14.
BACKGROUND AND PURPOSE
The subplate layer and intermediate zone are the precursors for neonatal white matter. The aims of this study were to evaluate 1) T1 and T2 signal intensity, and 2) FA of subplate and intermediate zone in postmortem fetuses and correlate with histology, and 3) T2 signal intensity of subplate and intermediate zone on antenatal MR imaging.
MATERIALS AND METHODS
Fourteen immersion-fixed normal brains from 18 to 25 gestational weeks underwent 1.5T MR imaging, including DTI and histologic examination. The subplate and intermediate zone were graded on a scale of 1-5 on T1 and T2, and FAs were evaluated and then correlated with age. Seventeen antenatal MR images from 20 to 26 gestational weeks with normal brain were evaluated by using the same grading.
RESULTS
On T1 postmortem MR imaging, subplate has lower signal intensity compared with intermediate zone; subplate signal intensity correlated positively (r = 0.66, P = .012) with age, and intermediate zone signal intensity correlated negatively (r = -0.78, P = .001) with age. On T2 postmortem MR imaging, subplate has higher signal intensity compared with intermediate zone and remained persistently high in signal intensity; intermediate zone signal intensity showed moderate correlation (r = 0.48, P = .086) with age. FA of subplate correlated positively (r = 0.55, P < .001) with age; FA of intermediate zone correlated negatively (r = -0.64, P < .0001) with age. On histology, extracellular matrix decreased and cellularity increased in subplate layer, tangentially organized cellularity decreased, and projecting fibers became thicker in intermediate zone with increasing gestation. The findings on T2-weighted antenatal MR imaging were similar to T2-weighted postmortem MR imaging.
CONCLUSIONS
The changes in signal intensity and FA of subplate and intermediate zone in the second trimester reflect microstructural changes on histology.
背景与目的
基板层和中间带是新生儿白质的前体。本研究旨在评估 1）基板层和中间带的 T1 和 T2 信号强度，2）与组织学的相关性，以及 3）产前磁共振成像的基板层和中间带的 T2 信号强度。
材料与方法
18 至 25 孕周的 14 例浸泡固定正常脑进行 1.5T MR 成像，包括弥散张量成像和组织学检查。在 T1 和 T2 上，基板层和中间带分别按 1-5 级评分，评估 FA 值，然后与年龄相关。对 20 至 26 孕周的 17 例正常脑产前磁共振成像进行相同评分。
结果
在尸体 T1 磁共振成像上，基板层的信号强度低于中间带；基板层的信号强度与年龄呈正相关（r = 0.66，P =.012），而中间带的信号强度与年龄呈负相关（r = -0.78，P =.001）。在尸体 T2 磁共振成像上，基板层的信号强度高于中间带，且信号强度持续较高；中间带的信号强度与年龄呈中度相关（r = 0.48，P =.086）。基板层的 FA 值与年龄呈正相关（r = 0.55，P <.001）；中间带的 FA 值与年龄呈负相关（r = -0.64，P <.0001）。组织学上，基板层的细胞外基质减少，细胞增多，切线排列的细胞减少，中间带的投射纤维随胎龄增加而变粗。产前 T2 加权磁共振成像的发现与尸体 T2 加权磁共振成像相似。
结论
妊娠中期基板层和中间带的信号强度和 FA 值的变化反映了组织学上的微观结构变化。
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