Radiofrequency Transmit and Receive Upgrade for 3T Research Scanner

描述（由申请人提供）：我们建议在肯尼迪克里格（KKI）雨果莫泽研究所的F.M. Kirby研究中心升级我们的3T研究扫描仪的射频（RF）能力。目的是通过1)将射频传输能力扩展到并行传输（TX）并升级到系统版本3.0，以及2)将用于脑部研究的头线圈元件数量增加到32个接收通道，保持最先进的MRI核心设施。这对于解决KKI和约翰霍普金斯大学（JHU）的许多研究人员的需求是必要的，这些研究人员目前有20个nih资助的项目，这些项目有几个目标，可以从这次升级提供的改进的技术能力中受益匪浅。这些研究人员使用F.M. Kirby研究中心的3T系统对大范围疾病和发育障碍进行结构MRI、功能MRI （fMRI）、定量生理MRI、磁共振波谱（MRS）和光谱成像（MRSI）以及弥散张量成像（DTI）。该提议的仪器将提供以下好处：1)体线圈TX /Release 3.0系统：将我们升级到最新的系统软件和硬件，并扩展我们的多通道（并行）RF传输能力。后者允许射频发射场优化（B1+ shimming），以减少3T时的介电阴影，这是由射频波长在受试者尺寸的顺序上引起的。这对于均匀的图像强度和对比度很重要，这有利于定量评估组织体积、代谢物水平和其他生理参数。此外，3.0版升级将允许动态逐片B0调整，为fMRI提供更高的局部信噪比、更少的空间失真和更好的时间稳定性。2) 32通道仅接收头部线圈：目前，所列资助的脑研究使用8通道接收线圈。与此相比，32通道线圈将皮质信噪比（SNR）提高了50%以上，并且线圈设计允许在所有三个方向上有效地使用高加速因子SENSE成像。这是由于噪声放大因子（g因子）的大幅降低，根据加速度和使用方向的不同，可以降低40-80%以上。这些主要优势可用于：a)更好地检测小信号（MRS）或小信号变化（fMRI）；B)提高所有模态的空间分辨率；c)减少扫描时间（即，产生更短的扫描时间），特别是在结构MRI和MRSI的3D采集序列中；d)减少快速单次采集的空间扭曲，例如用于DTI和fMRI。这种3T射频发射/接收升级对于我们机构中由NIH/NCRR研究资源的核心设施提供服务的NIH资助的研究人员的持续高质量的最新研究至关重要。

DESCRIPTION (provided by applicant): We propose to upgrade the radiofrequency (RF) capabilities of our 3T research scanner at the F.M. Kirby Research Center of the Hugo Moser Research Institute at Kennedy Krieger (KKI). The purpose is to remain a state-of-the-art MRI core facility by 1) extending the RF transmit capabilities to parallel transmit (TX) and upgrading to system release 3.0, and 2) increasing the number of head coil elements for brain studies to 32 receive channels. This is necessary to address the needs of many investigators at the KKI and Johns Hopkins University (JHU) who presently have 20 NIH-funded grants with several aims that can strongly benefit from the improved technical capabilities provided by this upgrade. These investigators use the 3T system in the F.M. Kirby Research Center for structural MRI, functional MRI (fMRI), quantitative physiological MRI, magnetic resonance spectroscopy (MRS) and spectroscopic imaging (MRSI), and diffusion tensor imaging (DTI) of a large range of diseases and developmental disabilities. This proposed instrumentation will provide the following benefits: 1) Body coil TX /Release 3.0 system: upgrades us to the latest system software and hardware and expands our capabilities to multi-channel (parallel) RF transmit. The latter allows for RF transmit field optimization (B1+ shimming) to reduce dielectric shading at 3T, caused by the RF wavelength being on the order of the subject size. This is important for homogeneous image intensity and contrast, which benefits quantitative assessment of tissue volumes, metabolite levels, and other physiological parameters. In addition, the Release 3.0 upgrade will allow dynamic slice-by-slice B0 adjustment, providing increased local SNR, reduced spatial distortions, and better temporal stability for fMRI. 2) 32-channel 1H receive-only head coil: Currently, the brain studies in the grants listed use the 8- channel receive coil. Compared to this, the 32-channel coil increases cortical signal-to-noise ratio (SNR) by more than 50% and the coil design allows the efficient use of high acceleration factor SENSE imaging in all three directions. This is due to a large reduction in the noise-amplification factor (g-factor), which can be more than 40-80% depending on the acceleration rate and directions used. These primary advantages can be used to: a) better detect small signals (MRS) or small signal changes (fMRI); b) increase spatial resolution for all modalities; c) reduce scan times (i.e., yield shorter scans) for especially in 3D acquisition sequences for structural MRI and MRSI; d) reduce spatial distortions in fast single-shot acquisitions, such as used for DTI and fMRI. This 3T RF transmit/receive upgrade is essential for continued high-quality state-of-the-art research for the NIH-funded researchers at our institutions who are served by the core facilities of our NIH/NCRR Research Resource. PUBLIC HEALTH RELEVANCE: The proposed system upgrades will benefit all researchers using the F.M. Kirby Research Center at the Hugo Moser Research Institute at Kennedy Krieger. The Center provides a core magnetic resonance facility within an interdisciplinary environment for the investigation of human anatomy, function and physiology. Cognitive functions including memory, attention, reading ability, and others are studied in conditions such as autism, Rett syndrome, and many other developmental disabilities. Other clinical applications include imaging studies of cancer (brain, breast), Huntington's disease, Alzheimer's disease, HIV, multiple sclerosis, cardiac disease, and rare metabolic disorders.