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: 9224993
• 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 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9224993
• 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 Imaging; 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（由申请人提供）：该项目的目的是测试以下联合假设：更快地采样功能性 MRI (fMRI) 信号可以帮助提取与神经元信号传导相关的信息；形成功能磁共振成像的基础，而不是像人们普遍认为的那样反应迟缓，而是对神经活动做出快速而精确的反应，通常主张快速采样以实现生理噪声消除——因为这些系统噪声源可以被充分采样，因此不会被忽略。原始 fMRI 信号中存在混叠，但我们的目标是证明短时间尺度的 fMRI 信号也包含由神经激活直接驱动的波动，而众所周知，血氧水平依赖性 (BOLD) 响应会达到峰值。神经元活动开始后 6 秒，初始血管反应在不到 1 秒内开始，我们将利用我们最近开发的同步技术来挑战 BOLD 反应“缓慢”的观点。用于 fMRI 的多切片 (SMS) 成像，提供比传统技术快 12 倍的时间采样，通过 SMS 方法，fMRI 测量具有时间分辨率，可以以亚秒级精度检测整个大脑的大脑活动。先前的工作已经证明，以高采样率获取的功能磁共振成像时间序列数据可用于将全球大脑网络分割成更小的节点，从而提高静息态功能连接研究中的检测能力。在这里，我们建议将这一关键优势扩展到其他常见的领域。功能磁共振成像范式实验。初步数据表明，通过使用传统的任务驱动模块设计范例在更精细的时间尺度上获取 fMRI 数据，可以将检测灵敏度大幅提高至 2-3 倍。在这些情况下，更快的采样可以提高灵敏度。这种推动将使新类型的实验以及单受试者分析和潜在的个体化诊断成为可能。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，BOLD 反应的早期阶段是由局部血管反应精确控制的。大胆的回应因此，高时空分辨率的 fMRI 采集可以通过对 BOLD 响应的早期阶段进行采样来实现更高的准确性。最后，我们将测试快速 fMRI 是否有助于 (i)。从连续的、时间编码的刺激设计中提取信息，并且（ii）解决及时发生的神经激活，对于后者，我们将实施一种新颖的校准程序，旨在从测量到的 BOLD 响应延迟中消除血管延迟的区域变化。在这里，更快的采样可以产生有关大脑神经功能和激活潜伏期的额外信息，我们的目标是展示快速功能磁共振成像在这些领域的好处，并为不可避免的广泛使用开发采集和分析框架。这种革命性的功能磁共振成像新方法。