Conformal pediatric whole-head MEG system with optically-pumped magnetometers

 描述(申请人提供)：在从出生到学龄前的关键年龄段，我们对正常和异常大脑功能发育的理解存在很大差距。这些差距在很大程度上是由于在信息处理过程中非侵入性地检查脑区之间动态时空相互作用的演变的有限方法，其中小的头部尺寸排除了脑磁图(MEG)，使得只有脑电(EEG)的空间分辨率相对较低。我们建议开发一种脑磁图系统，能够在不进行信号平均的情况下，在单次试验中检测儿童触觉刺激产生的体感诱发磁场(SEF)。我们将评估与脑电(EEG)和现有最好的儿科脑磁图系统(BabyMEG)相比，使用建议的系统更好地分离离散皮质源的能力。该系统基于非制冷微制造光泵磁强计(µOPM)，而不是传统MEG系统中使用的超导量子干涉器件(SQUID)。这种新型传感器可以实现：1)可以适合任何大小和形状的磁头的MEG；2)每个µOPM探头和头皮之间的最小间隙(&lt；4 mm)，以提高信号强度；3)占地面积小，允许非常接近的传感器间距(~15 mm)，以提高空间分辨率；以及4)并行制造大晶片，这可以降低运营和系统成本。我们展望了未来的系统，它在成本、通用性和易用性方面都更类似于脑电系统。我们有三个具体目标：目标1A：开发一个高灵敏度的1通道µOPM磁强计系统，磁力计具有&lt；7 FT/vHz噪声电平和200 Hz带宽。目标1B：实现基线为2厘米、噪声水平为&lt；10 ft/vhz、共模抑制比(CMRR)为150的µOPM梯度计。目的2A：研制通道梯度仪脑磁图系统。我们将改进我们的大规模制造µOPM探头的方法，通过开发并行制造工艺而不是串行制造工艺，强调简化以降低成本、重复性和质量控制。目的2B：在美国国家标准与技术研究所(NIST)的标准二层MSR中，在一名体模和健康成年志愿者上组装和测试通道µOPM脑磁图系统。目的3A：在波士顿儿童医院的脑磁图设施中评估经络系统在健康儿童(0-36个月)中的作用，重点是在单项试验中检测自发性耳聋和确定定位误差。目标3B：评估系统的能力 定位癫痫患者(1-3岁)的发作间期发生器，并分离多个发生器。通过直接比较来自µOPM MEG和基于来自健康儿童和癫痫患者的SQUID的375通道儿科MEG系统(“BabyMEG”)的数据，我们期望不仅证明用于MEG的µOPMS的可行性，而且还能将更好的MEG图像与实际优势相结合。

 DESCRIPTION (provided by applicant): There are major gaps in our understanding of the development of normal and abnormal brain function in the critical years from birth to preschool. These gaps are due in large part to limited methods for non-invasively examining the evolution of dynamic spatiotemporal interactions between brain regions during information pro- cessing, where small head size rules out magnetoencephalography (MEG), leaving only electroencephalography (EEG) with relatively poor spatial resolution. We propose to develop a MEG system that could be able to detect somatosensory evoked magnetic field (SEF) in children produced by tactile stimulation on single trials without signal averaging. We will evaluate the ability to better separate discrete cortical sources with the proposed system as compared to electroencephalography (EEG) and the best pediatric MEG system available (babyMEG). The proposed system is based on uncooled microfabricated optically-pumped magnetometers (µOPM) instead of the Superconducting QUantum Interference Devices (SQUIDs) used in conventional MEG systems. The new type of sensors could enable: 1) a MEG that can fit the head of any size and shape, 2) minimal gap (< 4mm) between each µOPM probe and the scalp for increased signal strength, and 3) a small footprint allowing very close sensor spacing (~15 mm) for improved spatial resolution, and 4) manufacturing on large wafers in parallel, which can reduce operating and system cost. We envision a system in the future, which is much more similar to and EEG system with respect to cost, versatility, and ease of use. We have 3 specific aims: Aim 1A: Develop a highly sensitive 1-channel µOPM MEG system with a magnetometer having <7 fT/vHz noise level and 200 Hz bandwidth. Aim 1B: Implement a µOPM gradiometer with a baseline of 2 cm, a noise level of <10 fT/vHz, and a common-mode rejection ratio (CMRR) of 150. Aim 2A: Develop a 64-channel gradiometer MEG system. We will refine our method for large-scale fabrication of the µOPM probes, emphasizing simplification for cost reduction, reproducibility, and quality control by developing a parallel fabrication process instea of a serial one. Aim 2B: Assemble and test the 64-channel µOPM MEG system on a phantom and healthy adult volunteers in a standard 2-layer MSR at the National Institute of Standards and Technology (NIST). Aim 3A: Evaluate the 64-channel system in healthy children (0-36 months) at the MEG facility of Boston Children's Hospital (BCH) with a focus on detecting SEFs in single trials and determining localization errors. Aim 3B: Evaluate the ability of the system to localize interictal generators in epilepsy patients (1-3 years) and separate multiple generators. By directly comparing data from the µOPM MEG and a 375-channel pediatric MEG system ("babyMEG") based on SQUIDs from healthy children and epilepsy patients we expect to demonstrate not only the feasibility of µOPMs for MEG, but also better MEG images paired with practical advantages.