Prediction of Motor Outcome after Acute Stroke using Diffusional Kurtosis Imaging

使用扩散峰度成像预测急性中风后的运动结果

• 批准号: 8700634
• 负责人: DeAnna L Adkins
• 金额: $ 22.43万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-15 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8700634
• 关键词: Accounting; Acute; Address; Anisotropy; Axon; Biological Markers; Biophysical Process; Brain; Brain Injuries; Cellular Membrane; Cerebral cortex; Cerebrum; Clinical; Clinical assessments; Corticospinal Tracts; Cross-Sectional Studies; Data; Dendrites; Diagnostic; Diffusion; Diffusion Magnetic Resonance Imaging; Event; Forelimb; Histologic; Image; Immunohistochemistry; Individual; Intervention; Ischemia; Ischemic Brain Injury; Ischemic Stroke; Lead; Link; Measures; Methods; Metric; Modeling; Motor; Neurites; Organelles; Outcome; Patients; Prognostic Marker; Property; Protocols documentation; Public Health; Rattus; Recovery; Recovery of Function; Rehabilitation Outcome; Rehabilitation therapy; Signal Transduction; Staging; Stroke; Techniques; Testing; Tissues; Water; acute stroke; brain tissue; chronic stroke; density; design; disability; improved; motor function recovery; neuroimaging; physical property; post stroke; prognostic; public health relevance; sensorimotor system; stem; stroke recovery; tool; water diffusion; white matter

DESCRIPTION (provided by applicant): Approximately one-third of all stroke patients endure persistent motor disability after their initial stroke. Rehabilitative interventions are crucial fo promoting motor recovery aimed at improving patients' ability to independently manage daily activities. Decisions regarding the design of specific rehabilitation protocols are governed by the clinical assessment of a patient's potential for motor recovery, among other factors. Diffusion tensor imaging (DTI) is a promising tool for quantifying stroke- related microstructural brain damage thought to be associated with eventual functional recovery. For chronic stroke, several DTI studies have demonstrated that poor motor function recovery is associated with low fractional anisotropy of water diffusion in the ipsilesional corticospinal tract. For acute stroke, however, corresponding DTI results have not been reliably demonstrated. Since delayed efforts for rehabilitation often lead to worse motor outcome, improved neuroimaging techniques for evaluating the potential for recovery during the acute stages of stroke would potentially be valuable for the planning of appropriate and timely rehabilitative intervention. In brain tissue, he presence of diffusion barriers, such as cellular membranes and organelles, causes water diffusion to be markedly non-Gaussian. Because DTI nonetheless assumes water diffusion to be Gaussian, its ability to characterize tissue microstructure is necessarily incomplete. To overcome this limitation, we have developed a clinically feasible diffusion MRI method that accounts for diffusional non-Gaussianity (i.e. kurtosis) called diffusional kurtosis imaging (DKI). Furthermore, diffusion metrics obtained from either DTI or DKI are bulk physical properties with no explicit link to tissue properties. To address this second limitation, we have developed a technique called cerebral microenvironment modeling (CMM) that provides estimates of specific tissue microstructural properties, such as neurite (i.e. axons and dendrites) density, orientation distribution and compartmental diffusion coefficients, by utilizing the diffusion metrics derived from DKI. Our overall hypothesis is that tissue properties obtained from our new CMM method are sensitive biomarkers of ischemic brain injury, which may be reliable prognostic indicators of motor function recovery after acute ischemic stroke. This hypothesis will be tested by the following Specific Aims: (1) to determine the relationship between CMM metrics and histologically defined brain cytoarchitecture after ischemic stroke; and (2) to investigate the association between CMM metrics and spontaneous and rehabilitation-induced motor recovery after stroke. Successful completion of this project will provide sensitive and biophysically interpretable biomarkers of spontaneous and rehabilitation-induced stroke recovery.

描述（由申请人提供）：大约三分之一的中风患者在首次中风后患有持续性运动障碍。康复干预对于促进运动恢复至关重要，旨在提高患者独立管理日常活动的能力。关于具体康复方案设计的决定由 在其他因素中，对患者运动恢复潜力的临床评估。扩散张量成像（DTI）是一种很有前途的工具，用于量化中风相关的微结构脑损伤，被认为与最终的功能恢复有关。对于慢性卒中，几项DTI研究表明，运动功能恢复不良与同侧皮质脊髓束中水扩散的低各向异性分数相关。对于急性中风， 然而，相应的DTI结果还没有得到可靠的证明。由于延迟的康复努力往往会导致更糟糕的运动结果，改善神经影像学技术，以评估在中风的急性期恢复的潜力可能是有价值的适当和及时的康复干预计划。 在脑组织中，扩散屏障（如细胞膜和细胞器）的存在导致水扩散明显非高斯。由于DTI仍然假设水扩散是高斯分布的，因此其表征组织微观结构的能力必然是不完整的。为了克服这一限制，我们开发了一种临床上可行的弥散MRI方法，该方法考虑了弥散非高斯性（即峰度），称为弥散峰度成像（DKI）。 此外，从DTI或DKI获得的扩散度量是与组织性质没有明确联系的体物理性质。为了解决这第二个限制，我们已经开发了一种技术，称为脑微环境建模（CMM），提供特定的组织微结构特性，如神经突（即轴突和树突）密度，方向分布和房室扩散系数的估计，通过利用来自DKI的扩散度量。 我们的总体假设是，从我们的新CMM方法中获得的组织特性是缺血性脑损伤的敏感生物标志物，这可能是急性缺血性卒中后运动功能恢复的可靠预后指标。该假设将通过以下特定目的进行检验：（1）确定CMM指标与缺血性卒中后组织学定义的脑细胞结构之间的关系;（2）研究CMM指标与卒中后自发和康复诱导的运动恢复之间的关系。 本项目的成功完成将为自发性和康复诱导的卒中恢复提供敏感的和生物学上可解释的生物标志物。