Simultaneous MEG and ULF MRI for Functional Imaging

同时进行 MEG 和 ULF MRI 进行功能成像

• 批准号: 7133816
• 负责人: ROBERT H KRAUS
• 金额: $ 69.59万
• 依托单位: LOS ALAMOS NAT SECTY-LOS ALAMOS NAT LAB
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-05 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7133816
• 关键词: anatomy; brain; clinical research; fasting; functional magnetic resonance imaging; human; lead; magnetic field; measurement

DESCRIPTION (provided by applicant): We propose a new noninvasive modality for simultaneous functional and anatomical imaging of the human brain. This will be the first instrument ever to noninvasively measure both anatomical information and direct consequences of neural activity with high temporal resolution. We propose to combine magnetoencephalography (MEG) with ultra-low field magnetic resonance imaging (ULF-MRI). MEG (and electroencephalography - EEG) is unique in the ability to noninvasively measure neural activity in the brain with millisecond temporal resolution. ULF-MRI is an exciting new technique for structural imaging at magnetic fields in the Microtel regime. Signals for MEG and ULF-MRI are both measured by superconducting quantum interference device (SQUID) sensors. Hence MEG and ULF-MRI can be simultaneously acquired by the same sensor array. While MR signals at low field are drastically reduced relative to high-field (HF), the exquisite sensitivity of SQUID sensors and ULF-MRI techniques outlined here will more than compensate. This new functional/structural imaging modality will enhance neuroimaging of the human brain by reducing or eliminating numerous sources of error associated with co-registration (typically 5-10 mm or more), as the function and structure will be acquired with a single instrument. HF-MRI can be accurately co-registered to the MEG neural activity using HF and ULF surface renderings. Moreover, as ULF-MRI is free from distortions caused by susceptibility variations, anatomical surfaces acquired at ULF can be used to correct HF image distortions using existing warping algorithms. Correcting these distortions will improve MEG source localization by more accurately describing the shape of the head volume and the cortical surface (an important source constraint). Finally, acquisition of ULF-MRI by an array of SQUID sensors will enable faster image acquisition using MR sensor array techniques, techniques also being explored at HF. Simultaneous MEG/ULF-MRI will prove to be a powerful and general tool in the quest to understand the dynamic functional/structural relationships in the human brain, basically how and where the brain works. It will be used to study cognitive processes, for noninvasive localization of pathology such as epilepsy, and for determining surgical outcome (by localizing function in relation to pathology), to name a few. While MEG/ULF-MRI will provide a powerful new neuroimaging tool, it will open the door for exciting future developments. A three-fold modality including simultaneous ULF-MRI, MEG and EEG could readily be envisioned with dense array EEG. Ultimately, it has been speculated that NMR signatures of neural currents may eventually lead to unambiguous localization of neural activity. While unambiguous tomographic localization of neural activity appears possible, the temporal resolution will likely be no better than tens of milliseconds. ULF-MRI that may lead to direct imaging of neural activity, even with modest temporal resolution, can be used to constrain the simultaneously acquired MEG signal, providing millisecond or better temporal resolution.

描述（由申请人提供）：我们提出了一种新的非侵入性的方式，同时功能和解剖成像的人脑。这将是有史以来第一台以高时间分辨率无创测量解剖信息和神经活动直接后果的仪器。我们建议将联合收割机脑磁图（MEG）与超低场磁共振成像（ULF-MRI）相结合。脑磁图（和脑电图-脑电图）是独特的能力，非侵入性测量神经活动的大脑与毫秒的时间分辨率。超低频磁共振成像是一种令人兴奋的新技术，在磁场中的Microtel制度的结构成像。MEG和ULF-MRI的信号都是由超导量子干涉器件（SQUID）传感器测量的。因此，MEG和ULF-MRI可以由同一传感器阵列同时采集。虽然低场MR信号相对于高场（HF）大幅减少，但这里概述的SQUID传感器和ULF-MRI技术的灵敏度将超过补偿。这种新的功能/结构成像模式将通过减少或消除与配准相关的许多误差源（通常为5-10 mm或更大）来增强人脑的神经成像，因为功能和结构将用单个仪器采集。使用HF和ULF表面渲染，HF-MRI可以准确地与MEG神经活动共配准。此外，由于ULF-MRI不受由磁化率变化引起的失真的影响，因此在ULF处采集的解剖表面可以用于使用现有的扭曲算法来校正HF图像失真。校正这些失真将通过更准确地描述头部体积和皮质表面的形状（重要的源约束）来改善MEG源定位。最后，通过SQUID传感器阵列采集ULF-MRI将能够使用MR传感器阵列技术实现更快的图像采集，HF也在探索这些技术。同时MEG/ULF-MRI将被证明是一个强大的和通用的工具，在寻求了解人类大脑中的动态功能/结构关系，基本上是如何和在哪里的大脑工作。它将用于研究认知过程，用于病理学（如癫痫）的非侵入性定位，并用于确定手术结果（通过定位与病理学相关的功能），仅举几例。虽然MEG/ULF-MRI将提供一种强大的新神经成像工具，但它将为令人兴奋的未来发展打开大门。密集阵列EEG可以很容易地设想包括同时ULF-MRI、MEG和EEG的三重模式。最终，据推测，神经电流的NMR签名可能最终导致神经活动的明确定位。虽然神经活动的明确断层定位似乎是可能的，但时间分辨率可能不会优于数十毫秒。ULF-MRI可以导致神经活动的直接成像，即使具有适度的时间分辨率，也可以用于约束同时采集的MEG信号，提供毫秒或更好的时间分辨率。