Higher Speed, Field and Spatial Resolution Brain 3D 1H MRS

描述（由申请人提供）：质子磁共振波谱（1H-MRS）观察到的代谢变化通常会增强高灵敏度但非特异性的MRI。事实上，在1.5特斯拉，1H-MRS到目前为止已经将来自MRI的解剖结构与癌症、阿尔茨海默病和帕金森病、MS、HIV、癫痫、中风创伤和其他神经和精神疾病的潜在代谢联系起来。因此，预计高B 0 e3 T磁场将为1H-MRS提供灵敏度、光谱和空间分辨率方面急需的提升。不幸的是，没有发生，尽管他们的数量激增，：300安装，和场强，高达9.4 T.最有用的二维和三维（2D，3D）1H-MRS技术向高场的转化受到以下因素的阻碍：（i）高射频（B1）功率要求和热沉积;（ii）短T2，降低信噪比（SNR）增益;（iii）化学位移位移误差;以及（iv）缺乏评估和显示大型数据集的软件。因此，仪器制造商无法提供高效、可靠的3D多体元技术，他们传统上将这一责任转移到公共资助的学术研究上。因此，这种竞争性延续的长期目标是开发方法来解决问题i-iv，以在更高的B 0下执行3D 1H-MRS，并实现临床研究的优势。我们对这些问题的反应是将我们成功的混合动力技术扩展到3 T和7 T。具体目标1是利用较短的T2，通过跨感兴趣体积（VOI）的最佳交织（每个多个切片的多个切片）来增强3D覆盖的SNR和采集效率。具体目标2是利用移位阿达玛脉冲克服每瓦RF功率B1场的下降，移位阿达玛脉冲仅需要一个切片的B1来顺序地激励多个切片。这将在非常强的选择性梯度下降低峰值和沉积功率，并减少化学位移位移。具体目标3是使用3D横向和横向Hadamard编码来定义VOI，利用非回波序列恢复在高B 0时较短T2损失的SNR。最后，具体目标4是开发新的后处理方法来检测和可视化不同代谢物空间分布之间的关系，以简化令人生畏的3D 1H MRS数据量。 该项目将导致增加检查中覆盖的人脑体积，提高定位精度以及空间和光谱分辨率，并缩短在更高磁场下质子光谱的采集时间。这些能力将加强对人类大脑和脊柱中破坏性（但通常是MRI不可见或非特异性发现）神经系统疾病的潜在代谢的研究，也可能提高我们监测其治疗有效性的能力。

DESCRIPTION (provided by applicant): Metabolic changes observed with proton-magnetic-resonance-spectroscopy (1H-MRS) often augment the highly sensitive but not specific MRI. Indeed, at 1.5 Tesla, 1H-MRS has so far linked anatomy from MRI with underlying metabolism in cancer, Alzheimer's and Parkinson's diseases, MS, HIV, epilepsy, stroke trauma and other neurological and psychiatric disorders. It was anticipated, therefore, that high, B0 e3 T, magnetic-fields would provide 1H-MRS a much needed boost in sensitivity, spectral and spatial resolution. That unfortunately, did not happen despite their proliferation in number, :300 installed, and field strength, up to 9.4 T. Translation of the most useful two and three dimensional (2D, 3D) 1H-MRS techniques to high-fields has been stymied by: (i) High radio-frequency (B1) power requirements and heat deposition; (ii) short T2s, reducing the signal-to- noise-ratio (SNR) gain; (iii) chemical shift displacement errors; and (iv) lack of software to evaluate and display the large data sets. Consequently, efficient, reliable 3D multivoxel techniques are not offered by instrument manufacturers, who traditionally shift this onus onto publicly-funded academic research. The long term goal of this competing continuation, therefore, is to develop methods to address issues i - iv to perform 3D 1H-MRS at higher B0s, and realize the advantages for clinical research. Our response to these problems is to extend to 3 and 7 T our successful hybrid techniques. Specific Aim 1 is to exploit the shorter T2s to enhance the SNR and acquisition efficiency of 3D coverage by optimal interleaving across the volume-of-interest (VOI), multiple slabs of several slices each. Specific Aim 2 is to overcome the declining B1 fields per watt RF power with shifted-Hadamard pulses that need the B1 of just one slice to sequentially excite several. This will lower the peak and deposited power under very strong selective gradients and reduce the chemical shift displacement. Specific Aim 3, is to recover the SNR lost to shorter T2s at high B0s with non-echo sequences using 3D transverse and longitudinal-Hadamard encoding to define the VOI. Finally, Specific Aim 4 is to develop new post-processing methods to detect and visualize relationships between different metabolites' spatial distributions to simplify the daunting amounts of 3D 1H MRS data.PROJECT NARRATIVE This project will lead to increases in the amount of human brain volume covered in an exam, improve the localization accuracy as well as spatial and spectral resolution and shorten the acquisition time for proton spectroscopy at higher magnetic fields. These capabilities will enhance studies of the underlying metabolism of devastating (but frequently MRI-invisible or of non-specific finding) neurological diseases in the human brain and spine and may also improve our capability to monitor the effectiveness of their treatment(s).