Moving MRI: Imaging a Moving Body with a Moving MRI Magnet

为了响应脑RFA-EB-19-001，我们建议演示一种新的无创脑成像方法， 移动磁共振成像(MMRI)。在mMRI中，高分辨率、高场、超导磁共振磁体的运动使得 受试者的头部和身体相对于磁铁有效地保持静止。(这既不是便携式的，也不是 头戴式核磁共振。)通过消除磁头和磁体之间的相对运动，大量运动伪影 在很大程度上被压制了。 移动核磁共振将首次能够记录受试者的高质量解剖和功能图像 体验真正的运动刺激(即旋转、倾斜和平移)。与神经元激活相关的 因此，功能磁共振成像(FMRI)可以揭示前庭系统的自然刺激。三个人- 脑组织的空间变形和液体置换可以使用位移和流动来绘制地图- 灵敏的磁共振成像，应用于创伤性脑损伤(TBI)和航空航天生理学。脑功能 对前庭刺激的反应网络可能会被研究以增强我们对前庭生理学的知识 或诊断前庭偏头痛等疾病。响应运动的组织变形可能是 安全、非侵入性和实时的研究，产生准确的组织应变三维地图 张量、血液和滑液的灌流和流动。 超导磁体新技术(主线圈导冷的无冷源磁体 通过电力驱动的制冷机，同时消除对液氦或氮气的需求)成为可能 核磁共振磁体的结构，可以在野外安全地倾斜和移动。我们实验室有这样一个 该磁体已经过测试，以确认其在动态倾斜和平移条件下的高场稳定性。 在这个项目中，这个磁铁将配备一个简单的运动平台来展示mMRI的概念。 虽然临床和实验室的前庭测试都使用运动平台，但高空间分辨率成像 这些运动应用程序的技术并不存在。尽管方法论，如 脑电(EEG)，不提供高空间分辨率，以及功能性近红外 光谱学(Fnirs)只能成像皮质表面，是为人类研究而建立的mmri。 承诺将高质量的信息丰富的成像技术引入运动过程中的大脑激活领域。这 可以为我们理解运动过程中的大脑激活带来独特的进步，这可能会极大地 推进TBI研究。 具体的目标是：1)使现有的无低温磁体能够通过简单的运动来移动 平台；2)在体模中展示解剖和功能mMRI，并在使用活体大鼠的先导研究中。 运动范例将包括大规模动态倾斜和地球垂直旋转。这项工作的最终目标是 是为开发人体规模的mMRI扫描仪奠定基础。

In response to BRAIN RFA-EB-19-001 we propose to demonstrate a novel noninvasive brain imaging method, Moving MRI (mMRI). In mMRI, a high resolution, high field, superconducting MRI magnet moves such that the subject's head and body effectively remain stationary with respect to the magnet. (This is neither portable nor head-mounted MRI.) By eliminating the relative motion between head and magnet, massive motion artifacts are largely suppressed. Moving MRI would for the first time enable recording of high quality anatomic and functional images in subjects experiencing true motion stimulation (i.e., rotations, tilts, and translations). Neuronal activation associated with naturalistic stimulation of the vestibular system can thereby be revealed with functional MRI (fMRI). The three- dimensional deformation of brain tissue and fluid displacement may be mapped using displacement- and flow- sensitive MRI, with applications to traumatic brain injury (TBI) and aerospace physiology. Brain functional networks responding to vestibular stimuli might be studied to enhance our knowledge of vestibular physiology or to diagnose disorders such as vestibular migraine. Tissue deformation in response to motion might be studied safely, noninvasively and in real time, yielding accurate three-dimensional maps of tissue strain tensors, and blood and synovial fluid perfusion and flow. New superconducting magnet technology (cryogen-free magnets in which the main coil is conduction-cooled by an electrically powered cryocooler while eliminating the need for liquid helium or nitrogen) makes possible the construction of MRI magnets that can be safely tilted and moved while at field. Our laboratory has such a magnet, which has been tested to confirm its high field stability under conditions of dynamic tilt and translation. In this project, this magnet will be equipped with a simple motion platform to demonstrate the concept of mMRI. While vestibular testing in both the clinic and laboratory uses motion platforms, high spatial resolution imaging technologies for these motion applications do not exist. Although methodologies such as electroencephalography (EEG), which does not offer high spatial resolution, and functional near-infrared spectroscopy (fNIRS), which can image only the cortical surface, are established for human research, mMRI promises to introduce high quality information-rich imaging to the field of brain activation during motion. This could yield a singular advance for our understanding of brain activation during motion that could dramatically advance TBI research. The specific aims are: 1) Adapt an existing cryogen-free magnet so that it can be moved via a simple motion platform; 2) Demonstrate anatomic and functional mMRI in phantoms, and in a pilot study using live rats. Motion paradigms will include large-scale dynamic tilt and Earth-vertical rotation. The ultimate goal of this work is to lay the groundwork for the development of a human-scale mMRI scanner.