Fast MRI at the Limit of Biological Temporal Resolution

生物时间分辨率极限的快速 MRI

• 批准号: 9428443
• 负责人: Jonathan Rizzo Polimeni
• 金额: $ 60.2万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9428443
• 关键词: Acceleration; Accounting; Advocate; Animals; Area; Biological; Blood; Blood Vessels; Blood flow; Brain; Brain region; Calibration; Clinical Research; Cognitive; Coupling; Data; Data Analyses; Data Compression; Deposition; Detection; Development; Diagnosis; Echo-Planar Imaging; Excision; Extravasation; Functional Magnetic Resonance Imaging; Goals; Human; Image; Imaging Techniques; Joints; Magnetic Resonance Imaging; Measurement; Measures; Methods; Motion; Motor; Motor Cortex; Neurons; Noise; Patients; Pattern; Phase; Physiologic pulse; Physiological; Physiology; Procedures; Resolution; Rest; Route; Sampling; Scanning; Sensitivity and Specificity; Series; Signal Transduction; Slice; Source; Specificity; Speed; Stimulus; Techniques; Technology; Testing; Time; Variant; Visual Cortex; Work; base; blood oxygen level dependent; brain electrical activity; design; experimental study; hemodynamics; human imaging; image reconstruction; imaging modality; imaging study; interest; neuroimaging; neurotransmission; neurovascular coupling; next generation; novel; novel strategies; optical imaging; public health relevance; reconstruction; response; retinotopic; spatiotemporal; temporal measurement; time interval; translational study; visual motor; visual receptive field; visual stimulus

 DESCRIPTION (provided by applicant): The objective of this project is to test the joint hypotheses that sampling the functional MRI (fMRI) signals up to an order of magnitude more rapidly can help extract information related to neuronal signaling; and that the hemodynamic signals that form the basis of fMRI, rather than being sluggish as is commonly believed, respond rapidly and precisely to neuronal activity. Rapid sampling is commonly advocated to enable physiological noise removal-because these systemic noise sources can then be adequately sampled and so are not aliased in the raw fMRI signal-however our goal is to demonstrate that the fMRI signal at short time scales also contains fluctuations that are directly driven by neuronal activation. While the blood-oxygen-level-dependent (BOLD) response is well known to peak 6 s following the onset of neuronal activity, the initial vascular response begins in less tha 1 s. Here we challenge the notion that the BOLD response is "slow". We will capitalize on our recent development of Simultaneous Multi-Slice (SMS) imaging for fMRI, which provides temporal sampling that is 12× faster than that of conventional techniques. With the SMS method, the fMRI measurement possesses the temporal resolution to detect brain activation over the entire brain with sub-second precision. Previous work has demonstrated that fMRI time series data acquired with high sampling rates can be used to parcellate global brain networks into smaller nodes, and therefore increase detection power in resting- state functional connectivity studies. Here we propose to extend this key benefit to other common fMRI experimental paradigms. Our preliminary data suggests that, by acquiring fMRI data on a finer time scale using a conventional task-driven block-design paradigm, dramatic increases in detection sensitivity up to factors of 2-3 are achievable. In these cases, faster sampling yields increased sensitivity. This boost will enable new classes of experiments, as well as single-subject analyses and potentially individualized diagnosis. Recent invasive animal neurovascular coupling studies and human fMRI studies have shown that the early stages of the BOLD response are precisely controlled by local vascular responses, and the BOLD response spreads spatially with time. High spatio-temporal resolution fMRI acquisitions can therefore enable higher accuracy by sampling the early phases of the BOLD response. In these cases, faster sampling yields increased specificity. Finally, we will test whether rapid fMRI can help (i) extrac information from continuous, temporally- encoded stimulus designs and (ii) resolve neuronal activations occurring closely in time. For the latter, we will implement a novel calibration procedure designed to remove regional variations in vascular delay from the measured delays in the BOLD response to accurately estimate the neuronal activation onset. Here, faster sampling yields additional information about neuronal function and activation latencies of the brain. Our aim is to demonstrate the benefits of rapid fMRI in these domains and to develop acquisition and analysis frameworks for the inevitable widespread use of this transformative new approach to fMRI.

 描述（由适用提供）：该项目的目的是测试关节假设，即对功能性MRI（fMRI）信号采样至数量级的信号更快地可以帮助提取与神经元信号相关的信息；并且是构成fMRI基础的血液动力学信号，而不是通常认为迅速而精确地反应神经元活性。通常提倡快速采样以实现生理噪声去除 - 因为这些全身性噪声源然后可以充分采样，因此在原始fMRI信号中不可混淆，我们的目标是证明fMRI信号在短时间内还包含由神经元激活直接驱动的波动。尽管神经元活性发作后，众所周知，血氧级依赖性（粗体）反应是众所周知的，但最初的血管反应始于较小的1 s。在这里，我们挑战了大胆响应是“缓慢”的观念。我们将利用fMRI的最近开发的同时多板板（SMS）成像，该成像提供的临时抽样比传统技术快12×。通过SMS方法，fMRI测量电位可以以亚秒的精度检测整个大脑的大脑激活的临时分辨率。先前的工作表明，以高采样率获取的fMRI时间序列数据可用于将全球大脑网络分类为较小的节点，因此在静止状态功能连接研究中增加了检测能力。在这里，我们建议将此关键好处扩展到其他常见的fMRI实验范式。我们的初步数据表明，通过使用常规任务驱动的块设计范式在最终时间尺度上获取fMRI数据，可以实现检测灵敏度的急剧提高至2-3的因素。在这些情况下，更快的采样会提高灵敏度。这种提升将使新的实验类别以及单个主体分析和潜在的个性化诊断。最近的侵入性动物神经血管耦合研究和人类功能磁共振成像研究表明，大胆反应的早期阶段由局部血管反应精确控制，而大胆的反应随时间在空间上扩散。因此，高时空分辨率fMRI获取可以通过对BOLD响应的早期阶段进行采样来实现更高的准确性。在这些情况下，更快的采样会产生提高的特异性。最后，我们将测试快速fMRI是否可以帮助（i）从连续的，暂时编码的刺激设计中提取的信息，以及（ii）解决及时紧密发生的神经元激活。对于后者，我们将实施一个新颖的校准程序，旨在从大胆响应中的测量延迟中消除血管延迟的区域变化，以准确估计神经元激活的开始。在这里，更快的采样得出有关大脑神经元功能和激活潜伏期的其他信息。我们的目的是证明在这些领域中快速fMRI的好处，并开发获取和分析框架，以不可避免地将这种变革性的新方法用于fMRI。