Radiofrequency Transmit and Receive Upgrade for 3T Research Scanner

描述(由申请人提供)：我们建议升级肯尼迪·克里格(KKI)雨果·莫泽研究所(KKI)F.M.柯比研究中心的3T研究扫描仪的射频(RF)能力。其目的是通过1)将射频发射能力扩展到并行发射(TX)并升级到系统版本3.0，以及2)将用于脑研究的头线圈元件的数量增加到32个接收通道，从而保持最先进的MRI核心设施。这对于满足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，他们目前有20笔由NIH资助的赠款，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)以及扩散张量成像(DTI)等多种疾病和发育障碍的检查。这项拟议的仪器将提供以下好处：1)Body线圈TX/Release 3.0系统：将我们升级到最新的系统软件和硬件，并将我们的能力扩展到多通道(并行)RF发射。后者允许RF发射场优化(B1+垫片)，以减少由于RF波长约为对象大小而引起的3T时的介电阴影。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，版本3.0的升级将允许逐个切片的动态B0调整，提供更高的局部SNR，减少空间失真，并为fMRI提供更好的时间稳定性。2)32通道1H接收型头部线圈：目前，资助中列出的脑研究使用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高效使用高加速因数感测成像。这是由于噪声放大系数(g因子)大幅降低，根据所用的加速速率和方向，g因子可超过40%-80%。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)提高所有模式的空间分辨率；c)减少扫描时间(即，产生更短的扫描)，特别是在结构MRI和MRSI的3D采集序列中；d)减少快速单次采集中的空间失真，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资助的研究人员的持续高质量最先进的研究至关重要，这些研究人员由我们的NIH/NCRR研究资源的核心设施提供服务。 与公共卫生相关：拟议的系统升级将使所有使用肯尼迪·克里格雨果·莫泽研究所F.M.柯比研究中心的研究人员受益。该中心在跨学科环境中提供核心磁共振设备，用于人体解剖、功能和生理学的研究。认知功能，包括记忆、注意力、阅读能力和其他，在自闭症、雷特综合症和许多其他发育障碍的情况下被研究。其他临床应用包括癌症(脑、乳腺)、亨廷顿病、阿尔茨海默病、艾滋病毒、多发性硬化症、心脏病和罕见代谢紊乱的成像研究。

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.