HIGHER SPEED, FIELD & SPATIAL RESOLUTION BRAIN 3D 1H MRS

描述（改编自申请人的摘要）：局部NNR光谱 (MRS)可观察到的脑质子（1H）代谢物水平目前使用 在许多肿瘤、中风、HIV感染的非侵入性研究中心， 多发性硬化症和老年痴呆症 为了覆盖很大一部分 目前的1H MRS技术交错二维切片，每个测量 分别由自旋回波序列。 不幸的是，交错是一个 有限的临床检查时间的低效使用，以及自旋回波 延迟引起信号的T1加权和J耦合调制。 因此，观察到的代谢物水平取决于特定的 使用定位方案，考虑到敏感性相对较低 这些疾病的变异小于30%。 的 申请人建议解决低敏感性问题， 序列依赖性，通过开发三维定位方法， 两种无回声、多体素1H MRS技术的组合（混合）： 化学位移成像（CS 1）与阿达玛光谱成像（HS 1）。 可以实现三个重要的好处。 第一，每相等测量 到那时，三维混合体将使灵敏度提高两到三倍 2-D交错采集（取决于是4个还是8个切片） 寻求）。 第二，因为混合电路是无回声的， 调制伪影和T2损失将是最小的，产生另外的25到 50%的灵敏度。 综合来看， 增加将大大提高代谢物的可靠性 水平评价 第三，因为软件的发展会导致 生成优化的脉冲序列，该方法可以在任何 能够产生整形脉冲的成像器。 由于价格昂贵， 屏蔽梯度不是本质上需要的，拟议的研究 将使多体素脑1H MRS可用于尚未配备 他们

DESCRIPTION (Adapted from Applicant's Abstract): Localized NNR spectroscopy (MRS) of observable brain proton (1H) metabolites levels is currently used in many centers for non-invasive studies of tumors, stroke, HIV infection, multiple sclerosis, and Alzheimer' disease. To cover a significant portion of the brain; current 1H MRS techniques interleave 2-D slices, each measured separately by a spin-echo sequence. Unfortunately, interleaving is an inefficient use of the limited clinical examination time, and the spin-echo delays cause T1-weighting and J-coupling modulations of the signals. Consequently the observed metabolite levels depend on the particular localization scheme used and the sensitivity is relatively low considering that the variation in these pathologies are less than 30 percent. The applicants proposed to address the issues of low sensitivity and sequence-dependence by developing 3-D localization methods using combinations (hybrids) of two non-echo, multivoxel 1H MRS techniques: Chemical Shift Imaging (CSl) with Hadamard Spectroscopic Imaging (HS1). Three significant benefits could be realized. First, per equal measurement time, 3-D hybrids will result in a two to three fold gain in sensitivity over 2-D interleaved acquisition (depending on whether 4 or 8 slices are sought). Second, because the hybrids are non-echo, the J- coupling modulation artifacts and T2 losses will be minimal, yielding another 25 to 50 percent of sensitivity. Combined, the overall three to five fold increase will provide a dramatic boost to the reliability of metabolite level evaluation. Third, because the development will result in software to generate optimized pulse sequences, the methods could be implemented on any imager capable of producing shaped pulses. Since expensive, fast shielded-gradients are not intrinsically required, the proposed research will make multivoxel brain 1H MRS accessible to sites not yet equipped with them.