Robust 3D MR spectroscopic imaging through multi-coil magnetic field shaping

项目总结 磁共振波谱成像(MRSI)是一种强大的、非侵入性的绘制人体代谢图谱的方法 大脑。核磁共振成像的内在化学特异性可以揭示出现的区域的代谢变化。 在标准MRI上无病理性改变。磁共振成像已成功地用于脑肿瘤的分类和 渗透、放射治疗和手术的计划，并帮助确定了一系列 神经退行性疾病，如多发性硬化症、阿尔茨海默病和癫痫。尽管它有很多优点 尽管如此，MRSI并不是一种广泛的成像方式，因为该方法受到长期的- 存在磁场不均匀的问题，这导致质量较低，因此重复性较差 数据。不完全的水分和脂肪抑制会进一步影响数据质量。在过去的十年里 我们开发了多线圈(MC)垫片，作为传统球面谐波的替代方案 垫片。通过控制矩阵中的电流，圆形直流线圈使磁场均匀 可以在整个人类大脑中改善到低于0.1ppm。在此续期申请中，我们建议 将我们在MC场操作方面的丰富经验和MC垫片的卓越性能应用于 在整个人脑中实现一致和可靠的磁共振成像性能。目标1专注于 MC垫片的实施及其与基于EPI的超高速MRSI的集成。MC技术将是 经过修改和扩展以产生局部压碎机梯度，以有效抑制脂质。目标2涉及到 通过在人脑上进行MC增强磁共振成像的验证。除了MC和MC之间的比较 传统的填充式磁共振成像，AIM 2还将建立受试者内和受试者间以及重测 再现性。此外，在4T时优化的MC设置将被转移到3T和7T，没有 修改，以证明基于MC的垫片与临床MR系统的兼容性。这个 当90%的MRSI体素启用时，MC增强的MRSI的实施和验证被视为完成 所有切片、所有对象和所有扫描仪都遵守严格的数据质量要求。虽然所有的神经学 疾病和病理可以从高保真磁共振成像中受益，目标3侧重于获得高质量、可靠的 肿瘤患者的核磁共振成像。许多肿瘤术后患者中金属植入物的存在，除了 与肿瘤相关的病理，影响磁场的均质性。MC垫片将用于 证明高保真磁共振成像可以在具有挑战性的临床受试者群体中实现。

PROJECT SUMMARY MR spectroscopic imaging (MRSI) is a powerful, non-invasive method to map the metabolic profile of human brain. The intrinsic chemical specificity of MRSI can reveal altered metabolism in regions that would appear non-pathologic on standard MRI. MRSI has successfully been used for brain tumor classification and infiltration, planning of radiation therapy and surgery and has helped to characterize a range of neurodegenerative diseases such as multiple sclerosis, Alzheimer's disease and epilepsy. Despite its merits and successes, MRSI is not a widespread imaging modality because the method is hampered by the long- standing problem of magnetic field inhomogeneity, which leads to lower-quality and thus less-reproducible data. Incomplete water and lipid suppression can compromise data quality even further. Over the last decade we have developed multi-coil (MC) shimming as an alternative to conventional spherical harmonics based shimming. By controlling the current in a matrix of generic, circular DC coils the magnetic field homogeneity can be improved to less than 0.1 ppm across the entire human brain. In this renewal application we propose to apply our extensive experience with MC field manipulation and the superior performance of MC shimming to achieve consistent and reliable MRSI performance across the human brain. Aim 1 is focused on the implementation of MC shimming and its integration with ultra-fast, EPI-based MRSI. The MC technology will be modified and extended to generate local crusher gradients for effective lipid suppression. Aim 2 is concerned with the validation of MC-augmented MRSI on the human brain. Besides comparisons between MC and conventional shimmed MRSI, Aim 2 will also establish intra- and inter-subject, as well as test-retest reproducibility. In addition, the MC setup optimized at 4 T will be transferred to 3 T and 7 T, without modifications, to demonstrate compatibility of MC-based shimming with clinical MR systems. The implementation and validation of MC-augmented MRSI is considered complete when >90% of MRSI voxels on all slices, all subjects and all scanners adhere to stringent data quality requirements. While all neurological disorders and pathologies can benefit from high-fidelity MRSI, Aim 3 focuses on obtaining high-quality, reliable MRSI on tumor patients. The presence of metallic implants in many post-surgery tumor patients, in addition to tumor-related pathology, compromises the magnetic field homogeneity. MC shimming will be used to demonstrate that high-fidelity MRSI can be achieved on a challenging, clinical subject population.