White Matter Cytoarchitecture in Preterm Infants

早产儿的白质细胞结构

• 批准号: 6542578
• 负责人: GARY P ZIENTARA
• 金额: $ 6万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-08 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6542578
• 关键词: bioimaging /biomedical imaging; brain imaging /visualization /scanning; brain morphology; clinical research; computer program /software; computer system design /evaluation; developmental neurobiology; fluid flow; human subject; image processing; magnetic resonance imaging; method development; myelination; patient oriented research; premature infant human

DESCRIPTION (provided by applicant): The main goal of this project is the development and application of an innovative non-invasive in vivo magnetic resonance imaging (MRI) method that represents a new 3D probe of the cytoarchitecture of the developing subcortical white matter (WM) of the unmyelinated preterm human infant brain. The creation of this tool can provide a unique, non-invasive microstructural monitor of both normal WM fiber tract development and the neuronal response to injury. The basic method and its sensitivity to WM injury is clearly demonstrated with preliminary results from preterm infants. The proposed method entails the quantitative determination of the 3D pulsatile extracellular fluid flow field (EFF) within the WM as observed using fast MRI. Its application is, notably, unique to the WM of the early preterm infant group gestational age (GA) approximately <36 weeks, that contains relatively larger extracellular space in unmyelinated WM, and is not now practically observable from the dense myelinated WM of infants GA approximately 40 weeks or adults. Observed pulsatile EFF is forced by the cardiac (arterial pulsation of the brain, an ideal endogenous physiological marker that the investigators exploit. By this method, effects of cardiac pulsation are differentiated by employing a bandpass filter in a Fourier (frequency) analysis of each individual vowel's signal from a fast echo planar dynamic MRI series. By the proposed method, the principal axis and magnitude of the EFF within each vowel will be determined from computations based on MRI time series recorded along each orthogonal direction. It is the hypothesis of this proposed study that the EFF principal flow axis is parallel to the localized intra-voxel WM fiber alignment axis, and the EFF flow magnitude is a function of the WM fiber density and extent of myelination, that is, the EFF directly reveals the subvoxel characteristics of the WM cytoarchitecture. No known non-invasive in vivo technique currently can provide such specific quantitative flow information, noting that Diffusion Tensor MRI contains several different signal contributions combined with that of extracellular water. The new method developed in this study will be applied to acquire and analyze 3D MRI data from 15 preterm infants and two term infants in each of two years, and produce a 3D visualization of the 3D EFF in each case. Results will be analyzed in conjunction with 3D DT-MRI results and segmentation results also obtained in each case to prove the hypothesis that EFF reveals quantitative details of WM cytoarchitecture. Further method refinements are planned.

描述（由申请人提供）：该项目的主要目标是开发和应用一种创新的非侵入性体内磁共振成像（MRI）方法，该方法代表了无髓鞘早产人类婴儿大脑发育中皮质下白色物质（WM）细胞结构的新3D探针。 该工具的创建可以提供一个独特的，非侵入性的微结构监测正常WM纤维束的发展和神经元对损伤的反应。 早产儿的初步结果清楚地表明了基本方法及其对WM损伤的敏感性。 所提出的方法需要定量测定的3D脉动细胞外液流场（EFF）内的WM观察使用快速MRI。 值得注意的是，它的应用对于胎龄（GA）约<36周的早期早产婴儿组的WM是独特的，其在无髓鞘WM中包含相对较大的细胞外空间，并且现在实际上不能从约40周的婴儿GA或成人的致密有髓鞘WM中观察到。 所观察到的搏动性EFF是由大脑的心脏（动脉）搏动推动的，这是研究人员利用的理想内源性生理标记。 通过这种方法，心脏搏动的影响是通过采用一个带通滤波器的傅立叶（频率）分析的每个单独的元音的信号从快速回波平面动态MRI系列区分。 通过所提出的方法，每个元音内的EFF的主轴和幅度将根据沿沿着每个正交方向记录的MRI时间序列的计算来确定。 本研究假设EFF血流主轴平行于局部体素内WM纤维排列轴，EFF血流幅度是WM纤维密度和髓鞘形成程度的函数，即EFF直接揭示了WM细胞结构的亚体素特征。 目前没有已知的非侵入性体内技术可以提供这种特定的定量流动信息，注意到扩散张量MRI包含几种不同的信号贡献与细胞外水的信号贡献相结合。 在这项研究中开发的新方法将被应用于采集和分析3D MRI数据从15个早产儿和两个足月婴儿在每两年，并产生一个3D可视化的3D EFF在每种情况下。 结果将结合3D DT-MRI结果和分割结果进行分析，以证明EFF揭示WM细胞结构定量细节的假设。 计划进一步改进方法。