Direct MEG/EEG detection using a novel MRI approach

使用新型 MRI 方法进行直接 MEG/EEG 检测

• 批准号: 9566019
• 负责人: PAUL A BOTTOMLEY
• 金额: $ 24.56万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-30 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9566019
• 关键词: Acceleration; Area; Autistic Disorder; BRAIN initiative; Blood; Brain; Cardiac; Cell Culture Techniques; Clinical; Craniocerebral Trauma; Data; Dementia; Detection; Development; Echo-Planar Imaging; Electrocardiogram; Electrodes; Electroencephalography; Electrophysiology (science); Environment; Epilepsy; Evoked Potentials; Fiber; Fourier Transform; Frequencies; Functional Magnetic Resonance Imaging; Goals; Grant; Human; Human Volunteers; Image; Linear Algebra; Link; Magnetic Resonance Imaging; Magnetism; Magnetoencephalography; Measures; Mental Depression; Methods; Modeling; Morphologic artifacts; Nervous system structure; Neurons; Noise; Operative Surgical Procedures; Oxygen; Phase; Physiologic pulse; Physiological; Play; Relaxation; Research; Resolution; Rest; Scalp structure; Scheme; Series; Signal Transduction; Sister; Source; Spectrum Analysis; Speed; Stroke; Sum; Technology; Testing; Time; Tissues; Trauma; United States National Institutes of Health; Visual; Water; base; brain electrical activity; brain tissue; brain volume; clinical Diagnosis; clinical diagnostics; cognitive function; cohort; cranium; density; detector; electrical measurement; imaging approach; imaging detection; imaging modality; innovative technologies; magnetic field; meetings; neurotransmission; novel; novel strategies; relating to nervous system; simulation; superconducting quantum interference device; tool; volunteer

This R21 grant responds to RFA-EY-17-001 “BRAIN Initiative: New Concepts and Early-Stage Research for Large-Scale Recording and Modulation in the Nervous System …for unique and innovative technologies in an even earlier stage of development … including new and untested ideas in the initial stages of conceptualization… where preliminary data would not be available”. Electroencephalography (EEG) and magnetoencephalography (MEG) which measures the magnetic fields associated with the neuronal currents are the only tools currently available to noninvasively measure electrical activity in human brain. They provide a wealth of information on brain electrical activity in epilepsy, dementias, autism, depression, stroke, and trauma for clinical diagnosis and surgical planning. Yet the neuronal currents detected by EEG electrodes are confounded by intervening brain, CSF, skull and scalp tissues, while MEG requires superconducting magnetometers and a quiet magnetic environment. Moreover, the signal sources in EEG and MEG are not spatially-encoded per se and pose an inverse problem without a unique solution. While magnetic resonance imaging (MRI) plays a key role in The Brain Initiative with fiber track mapping and functional MRI (fMRI) methods and it aught to be sensitive to EEG/MEG signals, attempts to use MRI to measure neuronal electrical activity have thus far proved inconclusive or null. The MEG signals range from 10-15 to 10-12 Tesla(T) during epileptic spikes, while MRI’s sensitivity to neuronal sources is estimated at only about 10-10 T. Support is sought to develop an entirely new MRI approach to directly measure MEG-modulated MRI signals using a spatial encoding scheme that provides exceptionally high intrinsic signal-to-noise ratios (SNR) and speed. The new method of localization–spectroscopy with linear algebraic modeling or SLAM–uses a greatly-reduced SNR-optimized gradient encoding set to directly localize signals from small volumes of brain tissue that can be arbitrarily segmented and resized post-acquisition, from scout MRI. Tests show that SLAM can deliver an SNR of ≈105, yielding a calculated sensitivity of 10-14-10-15T for the brain water signal in ~10ml volumes in ~30ms acquisitions (~30Hz bandwidth). Mechanistically, MEG/EEG modulation of MRI signals arises via the zero/low-frequency dipole-dipole component of the spectral density function, which is directly proportional to the spin-spin relaxation rate, 1/T2. The plan is to continuously apply T2-sensitive SLAM MRI at ~30 Hz to detect MEG/EEG modulations of ~10-14T signals over a meaningful ~30Hz EEG range in healthy human volunteers. Simultaneous MRI-compatible EEG will be used for reference to identify signals, detect artifacts and optimize detection of relevant signals. Studies to detect resting-state, visual- and audio-evoked potentials are planned. If successful, the grant would deliver noninvasive MRI-based localization and sizing of neuronal signal sources which might then be correlated directly with fMRI, fiber-tracking and other MRI metrics.

这项 R21 赠款响应 RFA-EY-17-001“BRAIN Initiative：新概念和早期研究 神经系统中的大规模记录和调制……用于独特和创新的技术 甚至是发展的早期阶段……包括概念化初始阶段的新的和未经测试的想法…… 无法获得初步数据”。脑电图 (EEG) 和脑磁图 （MEG）测量与神经元电流相关的磁场是唯一的工具 目前可用于无创测量人脑的电活动。他们提供了丰富的信息 临床上癫痫、痴呆、自闭症、抑郁症、中风和创伤的脑电活动 诊断和手术计划。然而，脑电图电极检测到的神经元电流受到以下因素的干扰： 介入大脑、脑脊液、颅骨和头皮组织，而 MEG 需要超导磁力计和 安静的磁环境。此外，EEG 和 MEG 中的信号源本身并未进行空间编码 并提出一个没有唯一解的逆问题。虽然磁共振成像 (MRI) 发挥着关键作用 纤维轨迹图和功能性 MRI (fMRI) 方法在大脑计划中的作用，它应该是 对 EEG/MEG 信号敏感，迄今为止尝试使用 MRI 来测量神经元电活动 被证明是不确定的或无效的。在癫痫尖峰期间，MEG 信号范围为 10-15 至 10-12 Tesla(T)，而 MRI 对神经元源的敏感性估计仅为 10-10 T 左右。 寻求支持开发一种全新的 MRI 方法来直接测量 MEG 调制的 MRI 使用空间编码方案的信号可提供极高的固有信噪比 (SNR) 和速度。新的定位方法——线性代数建模或 SLAM 光谱学——使用 大幅降低信噪比优化的梯度编码集，可直接定位来自小体积大脑的信号 采集后可以通过侦察 MRI 任意分割和调整大小的组织。测试表明SLAM 可以提供约 105 的 SNR，计算出约 10ml 中脑水信号的灵敏度为 10-14-10-15T 约 30ms 采集量（约 30Hz 带宽）。从机制上讲，MRI 信号的 MEG/EEG 调制 通过谱密度函数的零/低频偶极子-偶极子分量产生，它直接 与自旋-自旋弛豫率 1/T2 成正比。计划持续应用 T2 敏感 SLAM MRI ~30 Hz，可在健康的有意义的 ~30Hz EEG 范围内检测 ~10-14T 信号的 MEG/EEG 调制 人类志愿者。同步 MRI 兼容脑电图将用于参考识别信号、检测 伪影并优化相关信号的检测。检测静息状态、视觉和听觉诱发的研究 潜力已规划。如果成功，这笔赠款将提供基于 MRI 的无创定位和尺寸测量 神经元信号源可能会直接与功能磁共振成像、纤维追踪和其他磁共振成像指标相关。