Perfusion MRI for Multi-site Studies of Brain Function

动脉自旋标记(ASL)灌注核磁共振显示作为一种广泛可用的和定量的 静息脑功能的测量可作为精神疾病神经相关性的生物标记物 和神经疾病，用于测量药物对大脑的影响，并最终用于诊断 以及对个别患者的治疗监测。尽管ASL灌注核磁共振技术现在 在大多数MRI扫描仪平台上实施，社区对性能的不确定性 不同技术实施的差异以及如何跨中心和 MRI扫描仪平台限制了其在临床研究中的常规应用。 在我们成功开发量化方法和标准序列的基础上 在之前的资助周期中，我们建议专注于限制多中心研究的关键问题 与ASL合作。我们的第一个目标是通过以下方式测量ASL不同实现的相对敏感度 比较它们的重复性和对西酞普兰或阿普唑仑两种测试干预的反应 行政管理。这一目标的结果将是对区域探测功率的定量计算 影响以及实施的选择将如何影响功率和所需的样本量。 第二个目标是使用定制的图像采集和 血流灌注体模的构建。质量保证是整个影像研究的关键要素 但目前还没有确定的方法来测试ASL的血流灌注性能。 在我们的最终目标中，我们的目标是表征和减少由 与研究干预无关的大脑活动的变化，即所谓的生理性噪音。我们会 确定在ASL扫描期间执行中等要求的警戒任务是否有帮助 控制受试者的心理状态，在不过度刺激特定区域的情况下减少变异性 大脑的一部分。我们还将研究大脑网络活动引起的静息血流灌注波动，以 确定在图像处理过程中识别和消除这些波动是否有所改善 再现性。这一目的也将决定静息波动的幅度是否反映静息 灌流。由于通过血液氧合敏感的MRI测量的静息脑波动 越来越多地被用作静息功能的指标，在 波动和平均静息活动将解决功能成像中的一个悬而未决的问题。 这些目标的实现将加速和改善ASL作为大脑生物标志物的使用 在疾病中的作用，并将极大地改进许多有计划的和积极的多地点研究的设计 使用ASL。

Arterial Spin Labeling (ASL) perfusion MRI shows promise as a widely available and quantitative measure of resting brain function that can be used as a biomarker for the neural correlates of psychiatric and neurologic diseases, for the measurement of drug effects in the brain, and ultimately for diagnosis and treatment monitoring in individual patients. Although ASL perfusion MRI technologies are now implemented on most MRI scanner platforms, uncertainty in the community on the performance differences of various technical implementations and how to best use the technology across centers and MRI scanner platforms has limited its dissemination into routine use in clinical research. Building upon our successful development of quantification methods and standard sequences across platforms in the prior funding cycle, we propose to focus on the key issues limiting multi-center studies with ASL. Our first aim is to measure the relative sensitivity of different implementations of ASL by comparing their reproducibility and their response to 2 test interventions, citalopram or alprazolam administration. The result of this aim will be a quantitative calculation of power for detection of regional effects and how the choice of implementation will affect the power and required sample size. The second aim is to develop quality assessment methods using customized image acquisitions and the construction of a perfusion phantom. Quality assurance is a key element of imaging studies across sites, but there are no established methods for testing ASL perfusion performance. In our final aim, we target the characterization and reduction of variable perfusion signal induced by changes in brain activity unrelated to study interventions, so-called physiological noise. We will determine whether performing a moderately demanding vigilance task during the ASL scan will help control the subject's mental state and reduce variability without excessively stimulating particular regions of the brain. We will also study resting fluctuations in perfusion induced by network activity in the brain to determine if identifying and removing these fluctuations during image processing improves reproducibility. This aim will also determine if the amplitude of resting fluctuations is reflective of resting perfusion. Since resting brain fluctuations as measured by blood oxygenation sensitive MRI are increasingly being used as an indicator of resting function, establishing a relationship between fluctuations and average resting activity will address an outstanding question in functional imaging. Achievement of these aims will accelerate and improve the use of ASL as a biomarker for brain function in disease and will greatly improve the design of numerous planned and active multi-site studies employing ASL.