9.4Tesla/310mm MR Imaging and Spectroscopy System

描述(由申请人提供)： 伊利诺伊州埃文斯顿基础核磁共振研究中心的科学家们申请部分资金支持，以购买一台9.4T/305毫米口径水平轴磁共振扫描仪，用于对兔子、大鼠和小鼠进行成像。该成像器将具有主动屏蔽超导磁体，并将配备两个集成的梯度垫片线圈、双通道射频发射器和双接收器系统。该中心与埃文斯顿西北医疗保健中心有主要联系，与西北大学作为罗伯特·H·卢里癌症中心的核心设施有次要联系。所要求的高场成像仪的理由是，目前使用的4.7T成像仪无法满足资助项目对更高空间分辨率、时间分辨率、信噪比和对比度噪声比的要求。对这一请求的支持以4.7T和不再运行的垂直轴Omega 400WB光谱仪上获得的数据的形式广泛提供。将使用建议的成像器的项目根据所采用的MR方法被分成三个部分：(I)功能成像，(Ii)扩散张量成像，和(Iii)新的对比度增强方法。使用清醒兔模型的功能神经成像项目包括学习、记忆、衰老、麻醉以及BOLD功能磁共振成像和潜在神经元活动之间的关系的研究。9.4T成像仪将通过增加小静脉和毛细血管的平方大胆对比度而使这些项目受益，而大血管的贡献最小。预计在9.4T时信噪比将提高两倍，这将使人们能够以更大的空间特异性来研究神经元电路中的结构。0.2mm3或以下的高空间分辨率对于研究皮质柱和皮质层等结构的激活或具有特异性的感觉-边缘-小脑系统的激活是必不可少的。五个项目使用扩散张量成像测量各向异性，以促进对阿尔茨海默病、肌萎缩侧索硬化症、多发性硬化症和缺氧缺血等神经疾病细胞环境变化的了解。脑和脊髓的各向异性测量将极大地受益于9.4T时可用信噪比的提高，因为这些测量的准确性受到低信噪比的严重影响。这些研究集中在小鼠脊髓灰质区和白质区或小鼠海马区CA1、CA3和DG区域的亚结构上，这些研究对高空间分辨率的要求只能通过9.4T成像仪提高的灵敏度来满足。造影剂领域的研究集中在开发靶向特异性造影剂以研究细胞迁移和信号转导，以及克服顺磁剂在高磁场下的局限性。指出了对购买成像仪的费用分摊提供强有力的机构支持。负责该仪器的科学人员在小动物成像方面拥有专业知识和经验。

DESCRIPTION (provided by applicant): Scientists at the Center for Basic M.R. Research, Evanston, Illinois request partial funding support to purchase a 9.4T/305mm bore horizontal axis MR scanner to image rabbits, rats and mice. The imager will have actively shielded superconducting magnet and will be fitted with two integrated gradient -shim coils, dual channel RF transmitter and dual receiver system. The center has primary affiliation to Evanston Northwestern Healthcare and secondary affiliation to Northwestern University as a core facility of the Robert H. Lurie Cancer Center. Justification of the requested high field imager is based on the demand for higher spatial resolution, temporal resolution, signal to noise ratio and contrast to noise ratio in funded projects that cannot be met by the 4.7T imager currently in use. Support for the request is presented extensively in the form of data obtained at 4.7T and on a vertical axis Omega 400WB spectrometer that is no longer operational. Projects that will use the proposed imager are described under three sections based on the MR methodology employed: (i) functional imaging, (ii) diffusion tensor imaging, and (iii) novel approaches to contrast enhancement. Functional neuroimaging projects that use a conscious rabbit model include studies of learning, memory, aging, anesthesia and the relationship between BOLD fMRI and underlying neuronal activity. The 9.4T imager will benefit these projects by increasing BOLD contrast quadratically for small venuoles and capillaries with minimal contribution from the large vessels. The two-fold increase in SNR expected at 9.4T will allow structures in neuronal circuitry to be studied with greater spatial specificity. High spatial resolution on the order of 0.2mm3 or less is essential to study activation in structures such as cortical columns and cortical layers or those in the sensory-limbic-cerebellar system with specificity. Measurement of anisotropy by diffusion tensor imaging is employed by five projects to advance understanding of changes to the cellular environment in neurological disorders such as AD, ALS, MS, and hypoxia-ischemia. Anisotropy measurements in brain and spinal cord will greatly benefit from the increased SNR available at 9.4T since accuracy in these measurements is severely affected by poor SNR. High spatial resolution requirements in these studies which focus on substructures within gray and white matter compartments of the mouse spinal cord or CA1, CA3 and DG regions in mouse hippocampus can only be met by the increased sensitivity of the 9.4T imager. Research in the area of contrast agents focuses on developing target-specific agents to study cell migration and signaling and on overcoming limitations of paramagnetic agents at high magnetic fields. Strong institutional support for cost-sharing in the purchase of the imager is indicated. Scientific staff responsible for the instrument has expertise and experience in small animal imaging.