Microstructural brain development after perinatal cerebral white matter injury assessed by diffusion tensor magnetic resonance imaging
Microstructural brain development after perinatal cerebral white matter injury assessed by diffusion tensor magnetic resonance imaging
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DOI：
10.1542/peds.107.3.455
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发表时间：
2001-03-01
期刊：
影响因子：
8
通讯作者：
Volpe, JJ
中科院分区：
文献类型：
--
作者：
H端ppi, PS;Murphy, B;Volpe, JJ
目标。早产儿的脑损伤主要表现为围产期获得性脑白质(WM)损害。这种损伤对脑WM后续发展的影响尚不清楚。本研究利用弥散张量磁共振成像(MRI)技术评价脑WM损伤对脑不同WM区微结构发育的影响。对20例早产儿(胎龄29.1+/-1.9周)在出生前3周内和足月再次行常规MRI检查，并在晚期行弥散张量MRI检查。其中10例早产儿经早期MRI确诊为脑白质损伤，并与10例胎龄相近、新生儿病程相似、但新生儿MRI扫描正常的早产儿配对。分别在冠状面和轴位采集弥散张量MRI图像，用来测量中央、前额、枕骨、颞叶和内囊后肢的表观弥散系数和相对各向异性(RA)，前者是水扩散的总体限制指标，后者是扩散的优先方向。根据扩散张量分析生成扩散向量图，以定义大脑WM区域的微结构。足月时，弥散张量MRI显示有或无围产期WM损害的早产儿的表观弥散系数无差异。相比之下，RA，即扩散的优先方向性的量度，因此依赖于轴突纤维和少突胶质细胞的发育，在最初的WM损伤的主要部位--中央WM，RA低25%。然而，RA在相对较轻的西医区域，如颞区、前额区和枕区未受影响。值得注意的是，内囊中含有来自受损的大脑WM的纤维，有WM损伤的婴儿的RA值比没有WM损伤的婴儿低20%。弥散向量图显示中心白质纤维束和下行至内囊的纤维束的大小、方向和组织发生了显著变化。围产期脑WM损伤似乎对随后大脑WM和更远端的纤维束的发育有重大的有害影响。新生儿脑损伤的最终影响不仅应被认为是组织破坏的功能，而且还应被视为损害随后的脑发育的功能。
Objective. Brain injury in premature infants is characterized predominantly by perinatally acquired lesions in the cerebral white matter (WM). The impact of such injury on the subsequent development of cerebral WM is not clear. This study uses diffusion tensor magnetic resonance imaging (MRI) to evaluate the effects of cerebral WM injury on subsequent microstructural brain development in different WM areas of the brain.Methods. Twenty premature infants (gestational age: 29.1 +/- 1.9 weeks) were studied by conventional MRI within the first 3 weeks of life and again at term, with the addition at the latter time of diffusion tensor MRI. Ten of the preterm infants had cerebral WM injury identified by the early MRI and were matched with 10 premature infants of similar gestational age and neonatal course but with normal neonatal MRI scans. Diffusion tensor MRI at term was acquired in coronal and axial planes and used to determine the apparent diffusion coefficient, a measure of overall restriction to water diffusion, and the relative anisotropy (RA), a measure of preferred directionality of diffusion, in central WM, anterior frontal WM, occipital WM, temporal WM, and the posterior limb of the internal capsule. Diffusion vector maps were generated from the diffusion tensor analysis to define the microstructural architecture of the cerebral WM regions.Results. At term, the diffusion tensor MRI revealed no difference in apparent diffusion coefficient among preterm infants with or without perinatal WM lesions. By contrast, RA, the measure of preferred directionality of diffusion and thereby dependent on development of axonal fibers and oligodendroglia, was 25% lower in central WM, the principal site of the original WM injury. However, RA was unaffected in relatively uninjured WM areas, such as temporal, anterior frontal, and occipital regions. Notably, RA values in the internal capsule, which contains fibers that descend from the injured cerebral WM, were 20% lower in the infants with WM injury versus those without. Diffusion vector maps showed striking alterations in the size, orientation, and organization of fiber tracts in central WM and in those descending to the internal capsule.Conclusions. Perinatal cerebral WM injury seems to have major deleterious effects on subsequent development of fiber tracts both in the cerebral WM and more distally. The ultimate impact of brain injury in the newborn should be considered as a function not only of tissue destruction, but also of impaired subsequent brain development.