Fully Compensated Dynamic Shim System for In Vivo MRI and MRS

描述（申请人提供）：功能MRI、弥散MRI、磁共振波谱和光谱成像在疾病和损伤的研究和诊断、指导手术治疗方面具有很大的潜力。所有这些方法都大大受益于高场强磁铁（3T及以上）增加的灵敏度，分辨率和对比度。然而，由于空气和组织之间的磁化率差异引起的磁场不均匀性（MFI）影响日益混杂，高磁场的优势尚未充分发挥出来。MFI导致MRI中的信号丢失和空间失真，以及mrs中的频谱分辨率和灵敏度的损失。这些伪影导致的可靠性损失是这些技术在临床应用中没有得到广泛应用的主要原因。目前的磁场均匀化方法（即闪烁）在小体积上工作得很好，但在更大的物体上却不够，比如整个人类的大脑。在过去的十年中，耶鲁大学的磁共振小组开发了动态垫片更新（DSU）技术，该技术可以大大改善扩展区域的磁场均匀性。DSU将一个全局三维问题划分为若干片，在这些片上可以获得足够的磁场均匀性。与多层MRI序列同步动态更新预先确定的切片垫片，确保所有切片的最佳均匀性。在成功完成第一阶段str拨款后，目前的第二阶段申请将继续朝着DSU商业化的方向努力。具体而言，DSU硬件将进一步完善，并与专业软件相结合，实现机组的自动设置。由于DSU比常规的shimming复杂得多，因此标准MR用户将为该设备的日常操作提供额外的软件。由于MFI影响体内核磁共振的几乎所有方面，DSU的成功商业化将对MRI和MRS的临床应用产生重大影响，因此可以标记为高度显著。公共卫生相关性：磁共振成像（MRI）和光谱学（MRS）是获得健康和疾病中完整人体组织的高质量图像和代谢谱的领先技术。不幸的是，样品引入的磁场强度的空间变化会严重降低MRI和MRS数据的质量，从而可能影响正常组织与病变组织的区分。目前的技术还不能完全消除空间磁场的变化。目前的项目重点是开发能够显著降低空间磁场变化的新技术，从而大大提高MRI和MRS数据质量。

DESCRIPTION (provided by applicant): Functional MRI, diffusion MRI and MR spectroscopy and spectroscopic imaging have great potential for the study and diagnosis of disease and injury, and guiding surgical therapy. All of these methods benefit greatly from the added sensitivity, resolution and contrast from high field strength magnets (3T and above). However, the advantages of higher magnetic fields have not been fully realized due to the increasingly confounding effects of magnetic field inhomogeneity (MFI) caused by magnetic susceptibility differences between air and tissue. MFI leads to signal loss and spatial distortion in MRI and loss in spectral resolution and sensitivity in MRS. The loss of reliability due to these artifacts is a major reason why these techniques have not seen wide use in clinical applications. Current methods of magnetic field homogenization (i.e. shimming) work well on small volumes but are inadequate over larger objects, like the entire human brain. Over the last decade, the MR group at Yale University has developed the technique of dynamic shim updating (DSU) which allows greatly improved magnetic field homogeneity over extended regions. DSU divides a global 3D problem into a number of slices over which adequate magnetic field homogeneity can be achieved. Dynamically updating the pre-determined slice shims in sync with the multi-slice MRI sequence ensures optimal homogeneity for all slices. Following a successful completion of the Phase I STTR grant, the current Phase II application continues the work towards commercialization of DSU. Specifically, DSU hardware will be further improved and combined with professional software to automatically set up the unit. Since DSU is significantly more complicated than regular shimming, additional software will be provided for the every day operation of the unit by standard MR users. Since MFI affects almost all facets of in vivo NMR, the successful commercialization of DSU will have major impacts on the clinical application of MRI and MRS and can thus be labeled as highly significant. PUBLIC HEALTH RELEVANCE: Magnetic resonance imaging (MRI) and spectroscopy (MRS) are the leading techniques to obtain high-quality images and metabolic profiles of intact human tissues in health and disease. Unfortunately, spatial variations in magnetic field strength introduced by the sample can severely degrade the quality of MRI and MRS data, such that distinction of normal from diseased tissues may be compromised. Current technology is not able to completely cancel the spatial magnetic field variations. The current project focuses on the development of novel technology that can significantly reduce spatial magnetic field variations, thus leading to greatly increased MRI and MRS data quality.