NON ECHO, 3-D LOCALIZED, BRAIN PROTON NMR SPECTROSCOPY

描述(摘自申请者摘要)：本地化NNR光谱学 目前使用可观察到的脑质子(1H)代谢物水平的(MRS) 在许多肿瘤、中风、艾滋病毒感染的非侵入性研究中心， 多发性硬化症和阿尔茨海默病。覆盖相当大的一部分 脑部；目前的1H MRS技术交织2-D切片，每个切片测量 通过自旋回波序列分开。不幸的是，交错是一种 低效利用有限的临床检查时间，自旋回波 延迟导致信号的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 使用了定位方案，考虑到灵敏度相对较低 这些病理变化不到30%。这个 申请者建议解决敏感度低和 通过开发三维定位方法来实现序列依赖性 两种无回声、多体素1H MRS技术的组合(混合)： 化学位移成像(CSL)和阿达玛光谱成像(HS1)。 可以实现三个显著的好处。第一，每等量度 随着时间的推移，3D混合技术将使感光度提高两到三倍 超过2-D交错采集(取决于4个或8个切片是 已寻求)。其次，因为混合动力车是无回声的，J-联轴器 调制伪影和T2损耗将降至最低，从而再产生25%到 50%的灵敏度。加在一起，总体上是三到五倍 增加将大大提高代谢物的可靠性 水平评估。第三，因为开发将导致软件 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，速度快 屏蔽-梯度并不是本质上必需的，拟议的研究 将使尚未配备的站点可以访问多体素Brain 1H MRS 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.