White Matter Diffusion MRI in Children With Early Stroke

早期中风儿童的白质扩散 MRI

• 批准号: 6869303
• 负责人: PAMELA A MOSES
• 金额: $ 18.91万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6869303
• 关键词: adolescence (12-20); age difference; bioimaging /biomedical imaging; brain imaging /visualization /scanning; brain injury; brain mapping; cerebral dominance; clinical research; diffusion magnetic resonance imaging; early experience; human subject; perinatal; stroke; white matter

DESCRIPTION (provided by applicant): A common goal of research on various developmental brain disorders is to understand how an insult to the system affects the subsequent development of the brain. Toward this objective, we have studied cognitive and brain development in children with unilateral pre- or perinatal brain lesions (PL) for over a decade. Our longitudinal, behavioral studies have shown that children with PL have milder deficits than adult patients, and in the domain of language, the mapping between lesion site and ensuing deficits differs from adults. The mildness of children's impairments and the mismatch in functional mapping suggests an alteration in the structure and organization in the neural substrate. To examine the macroanatomic structure of the intact brain, we previously used noninvasive magnetic resonance imaging (MRI) techniques. The MRI analysis of neuroanatomical brain development revealed reduced cerebral white matter (WM) volume in both the ipsilesional and contralesional hemispheres. The WM attenuation was region-specific and occurred in sites that would typically maintain projections to or through the site of injury. Heretofore the opportunity to examine WM tracts noninyasively has been limited by standard MRI techniques. In order to examine structural changes in intact WM fiber tracts following early disruption, this study will use diffusion weighted imaging (DWI) and quantitative analysis techniques. DWI is sensitive to the movement of water molecules. In the brain, cell membranes and myelin sheaths restrict the movement of water such that molecules moves more readily parallel to axon fibers than perpendicular to them. Thus DWI methods can be used to measure water movement (diffusion) and directionality (anisotropy) as indices to assess white matter integrity. To determine the extent and degree of WM alteration following early injury, we will image the brains of 20 children with unilateral PL (11-18 years old) and 40 sex- and age-matched control children. From the DWI datasets we will derive measures of diffusivity and anisotropy in regions of previously identified WM attenuation and in the major cerebral pathways. In addition, standard MRI methods will be used to measure longitudinal relaxation time (T1) and proton density (MO) to begin to differentiate types of WM disorder that may underlie abnormal anisotropy.

描述（由申请人提供）：对各种发育性脑部疾病的研究的一个共同目标是了解对系统的损伤如何影响大脑的后续发育。为了实现这一目标，我们对患有单侧产前或围产期脑损伤 (PL) 的儿童的认知和大脑发育进行了十多年的研究。我们的纵向行为研究表明，患有 PL 的儿童比成年患者有更轻微的缺陷，并且在语言领域，病变部位和随后的缺陷之间的映射与成人不同。儿童的轻微损伤和功能映射的不匹配表明神经基质的结构和组织发生了改变。为了检查完整大脑的宏观解剖结构，我们之前使用了无创磁共振成像（MRI）技术。大脑神经解剖学发育的 MRI 分析显示，同侧半球和对侧半球的脑白质 (WM) 体积均减少。 WM 衰减是区域特异性的，发生在通常会保持投射到或穿过损伤部位的部位。迄今为止，非侵入性检查 WM 束的机会受到标准 MRI 技术的限制。为了检查早期破坏后完整 WM 纤维束的结构变化，本研究将使用扩散加权成像 (DWI) 和定量分析技术。 DWI 对水分子的运动很敏感。在大脑中，细胞膜和髓鞘限制水的运动，使得分子更容易平行于轴突纤维运动，而不是垂直于轴突纤维运动。因此，DWI 方法可用于测量水运动（扩散）和方向性（各向异性），作为评估白质完整性的指标。为了确定早期损伤后 WM 改变的范围和程度，我们将对 20 名单侧 PL 儿童（11-18 岁）和 40 名性别和年龄匹配的对照儿童进行大脑成像。从 DWI 数据集中，我们将得出先前确定的 WM 衰减区域和主要大脑通路中的扩散性和各向异性的测量值。此外，标准 MRI 方法将用于测量纵向弛豫时间 (T1) 和质子密度 (MO)，以开始区分可能导致异常各向异性的 WM 疾病类型。