Two-dimensional MR Spectroscopic Characterization of HE

描述（由申请人提供）：本申请的主要目标是评价局部二维（2D）MR波谱技术（MRS），并明确检测肝性脑病（HE）中的大脑代谢物。发现早期改变在HE的诊断中非常关键。局部磁共振波谱是一种主要的生化工具，在表征非侵入性的几种代谢物在人体组织。优秀的一维（1D）磁共振波谱HE和其他病理已报告有前途的结果。然而，各种代谢物的光谱重叠一直是传统的一维MRS的主要关注点。某些代谢物，即谷氨酸，谷氨酰胺，GABA，肌醇，天冬氨酸，谷胱甘肽，和NAA和NAAG的乙酰基的光谱分析，已经复杂的严重重叠在1.5T。2D MRS似乎非常适合解决这种重叠问题。它彻底改变了核磁共振在生物大分子中的应用。其他研究人员先前尝试实现二维MR技术的局部化版本主要使用幻影解决方案，尽管使用非局部化2D技术从动物大脑报告了一些结果。除了迄今为止已成功地用1D MRS分配和分析的主要代谢物外，更多的代谢物尚待检测，它们在不同病理学中的各自作用尚待用2D MRS探索。GABA和其他脑代谢物可以使用局部2D COSY在HE中比传统的1D MRS更明确地检测。该项目的三个具体目标是：1）获取HE患者扣带回前部和基底节区的单像素二维COSY谱，2）记录HE患者苍白球整体Mill改变; 3）对HE患者进行神经精神和神经认知功能评估，并将MR表现与神经精神、神经认知功能进行相关性分析，血氨和肝功能检测结果采用多元回归分析。带有双侧表面“接收”线圈的AGE 1.5T MRI扫描仪（MRI Devices Corp.）与身体RF“发射”线圈结合将用于实现改进的信号检测。最小的光谱重叠导致更少的模糊分配和更好的定量谷氨酸/谷氨酰胺，GABA，肌醇，苏氨酸，葡萄糖，牛磺酸和谷胱甘肽，将是这项工作的主要成果。

DESCRIPTION (provided by applicant): The major goals of this application are to evaluate a localized two-dimensional (2D) MR spectroscopic technique (MRS) and to detect cerebral metabolites unequivocally in hepatic encephalopathy (HE). Detection of early changes is very critical in the diagnosis of HE. Localized MR Spectroscopy is a major biochemical tool in characterizing noninvasively several metabolites in human tissues. Excellent one-dimensional (1D) MR spectra of HE and other pathologies have been reported with promising results. However, spectral overlap of various metabolites has been a major concern with the conventional 1D MRS. Spectral analysis of certain metabolites, namely glutamate, glutamine, GABA, myo-inositol, aspartate, glutathione, and the aspartyl groups of NAA and NAAG, has been complicated by severe overlap at 1.5T. 2D MRS seems well suited to address this problem of overlap. It has revolutionized the applications of NMR in biological macromolecules. Previous attempts by other researchers to implement the localized versions of the two-dimensional MR techniques mainly used phantom solutions, although some results were reported from animal brains using a non-localized 2D technique. In addition to the major metabolites successfully assigned and analyzed so far with 1D MRS, more metabolites are yet to be detected and their respective roles in different pathologiesare yet to be explored using 2D MRS. A major hypothesis to be tested in this work is whether the changes of glutamine/glutamate, myo-inositol, aspartate, GABA and other cerebral metabolites can be detected using the localized 2D COSY more unambiguously in HE than the conventional 1D MRS. Three specific goals of this project will be: 1) to acquire the single-voxel based 2D COSY spectra in the anterior cingulate and the basal ganglia regions of HE patients; 2) to record the global pallidal Mill changes in HE patients; 3) to perform the neuropsychiatric and neurocognitive assessment in HE patients, and to correlate the MR findings with the neuropsycho-logical, blood ammonia and liver function test results using multivariate regression analysis. AGE 1.5T MRI scanner with a bilateral surface "receive" coil (MRI Devices Corp.) in combination with a body rf "transmit" coil will be used to achieve improved signal detection. Minimal spectral overlap leading to less ambiguous assignment and better quantitation of glutamate/glutamine, GABA, myo-inositol, threonine, glucose, taurine and glutathione, will be a major outcome of this work.