Improved Spatial Resolution in Magnetoencephalography with an Optically Pumped Magnetometer Array

使用光泵磁力计阵列提高脑磁图的空间分辨率

• 批准号: 9552418
• 负责人: Peter D. D. Schwindt
• 金额: $ 69.98万
• 依托单位: SANDIA CORP-SANDIA NATIONAL LABORATORIES
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2019-03-26
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9552418
• 关键词: Acoustic Stimulation; Adult; Affect; Anterior; Area; Auditory; Auditory area; Brain; Brain Diseases; Brain imaging; Calibration; Child; Clinical; Communication; Cortical Column; Data; Development; Diagnosis; Discrimination; Early identification; Electroencephalography; Epilepsy; Frequencies; Functional Imaging; Functional Magnetic Resonance Imaging; Goals; Head; Helmet; Human; Individual; Lead; Longevity; Magnetism; Magnetoencephalography; Measurement; Measures; Neurons; Neurosciences; Noise; Operative Surgical Procedures; Optics; Outcome; Participant; Patients; Photic Stimulation; Positioning Attribute; Premature Infant; Pump; Research; Resolution; Scalp structure; Shapes; Signal Transduction; Source; Stimulus; System; Techniques; Temperature; Testing; Time; Variant; Visual; aged; attenuation; base; brain dysfunction; brain surgery; cost; cryogenics; design; developmental disease; flexibility; frontal lobe; human imaging; improved; insight; interest; magnetic field; millimeter; millisecond; neuroimaging; pediatric patients; prevent; relating to nervous system; response; sensor; signal processing; simulation; somatosensory; source localization; superconducting quantum interference device; temporal measurement; tool

Project Summary/Abstract The fixed helmet design of commercially available magnetoencephalography (MEG) systems utilizing superconducting quantum interference device (SQUID) magnetometers is designed to fit the 95th percentile of head size and therefore gives suboptimal measurements of the MEG signals for most subjects, especially children. A small head size will result in a gap between the helmet and head of several centimeters, and since the MEG signal amplitude decays as 1/r3, where r is the distance from the neuronal source, this large gap can result in signal attenuation by a factor of ~10. Therefore, placing the sensors on to the head will lead to increases in signal amplitude. Additionally, if sensors are placed on or near the scalp, high spatial frequency variations in the magnetic field will be detectable. Combining these factors, substantially improved spatial resolution in localizing neuronal sources will be enabled. Recent developments in sensor design now makes optically pumped magnetometers (OPMs) ideal for application to the field of MEG, and since they operate above room temperature and can be constructed as individual sensor modules, the sensor layout can be flexible. The long-term goal of this research is to develop a full-head MEG system based on OPMs that can conform to any head size to give the largest possible signal while at a reduced cost compared to cryogenic MEG. The objective of this proposal is to develop a 72-channel OPM MEG system giving partial head coverage to demonstrate improved spatial resolution in the measurement of nearby neuronal sources within the human brain. The system will be rapidly reconfigurable to concentrate the array coverage on an area of interest. Our central hypothesis is that the close proximity of the OPM array will allow a new level of spatial resolution for MEG. In Specific Aim 1, our current OPM-based MEG array with 20 channels will be expanded to a reconfigurable 72-channel system. The reconfigurable array will accommodate varying head sizes, particularly that of small adults and children, and the number of sensors will allow the array to be concentrated over two sections of the brain simultaneously. In Specific Aim 2, analysis techniques specific to the reconfigurable array will be developed. When the array is repositioned for each new subject, real-time array calibration is required for accurate magnetic source localization and external noise suppression. In addition, data simulation will optimize the positioning of the array and reveal the possible improvements in source localization due to access to signals of higher spatial complexity. In Specific Aim 3, the source localization precision between our OPM MEG array and a commercial SQUID-based MEG array will be compared. Tasks involving auditory and visual stimulation will allow us to study spatial variation of brain activity due to changing stimulus parameters. With the expected improvements in signal size and spatial resolution, higher fidelity MEG measurements for people of all head sizes ranging from premature infants to the largest adults are enabled, with broad ranging applications in neuroscience and in understanding and treating brain dysfunction.

项目总结/摘要 市售脑磁图（MEG）系统的固定头盔设计，利用 超导量子干涉仪（SQUID）磁强计的设计符合95百分位数的 头部尺寸，因此对于大多数受试者， 孩子小的头部尺寸将导致头盔和头部之间有几厘米的间隙， MEG信号幅度衰减为1/r3，其中r是距神经源的距离，该大间隙可以 导致信号衰减约10倍。因此，将传感器放置在头部将导致 信号幅度增大。此外，如果传感器被放置在头皮上或附近，高空间频率 磁场的变化将是可检测的。结合这些因素， 将能够实现定位神经元源的分辨率。传感器设计的最新发展使得 光泵磁力计（OPMs）是MEG领域应用的理想选择， 并且可以构造为单独的传感器模块，传感器布局可以 灵活.本研究的长期目标是开发一种基于OPM的全头部脑磁图系统， 符合任何头部尺寸，以提供最大可能的信号，同时与低温相比成本更低 MEG.本提案的目的是开发一个72通道的OPM MEG系统， 覆盖范围，以证明在测量内的附近神经元源时的空间分辨率提高 人类的大脑该系统将可快速重新配置，以将阵列覆盖范围集中在 兴趣我们的中心假设是，OPM阵列的紧密接近将允许新的空间水平， MEG的分辨率。在具体目标1中，我们目前基于OPM的20通道MEG阵列将扩展到 可重新配置的72通道系统。可重新配置的阵列将适应不同的头部尺寸， 特别是小的成人和儿童，传感器的数量将允许阵列集中 同时在大脑的两个区域进行在具体目标2中， 将开发可重构阵列。当阵列为每个新的主题重新定位时，实时阵列 需要校准来精确地定位磁源和抑制外部噪声。此外，本发明还提供了一种方法， 数据模拟将优化阵列的定位，并揭示源的可能改进 由于访问更高空间复杂度的信号而导致的定位。在《特定目标3》中， 我们的OPM MEG阵列和商业SQUID为基础的MEG阵列之间的精度进行比较。任务 包括听觉和视觉刺激将使我们能够研究大脑活动的空间变化， 刺激参数随着信号大小和空间分辨率的预期改善， 能够对从早产儿到最大的成人的所有头部尺寸的人进行测量， 在神经科学以及理解和治疗脑功能障碍方面具有广泛的应用。