REPRODUCIBILITY STUDY OF WHOLE-BRAIN SPECTRO IMAG WITH AUTOMATED QUANTIFICATION

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 简介： 脑H-MRSI已成为一种重要的临床工具，尽管被广泛使用，但大多数脑MRSI序列具有缺点，包括有限的空间覆盖、水和脂质抑制不足、扫描时间长、低SNR和缺乏鲁棒的自动光谱定量。为了解决这些局限性，我们实施了一种快速3D全脑1.5T MRSI序列，具有有效和稳健的水和脂质抑制、螺旋k空间读出轨迹和8通道相控阵线圈。在这项工作中，我们评估了序列和数据处理方法的可靠性和再现性。 方法和讨论： 将频谱空间90度RF脉冲和两个相同的双频带频谱空间180度脉冲并入PRESS序列中，用于定位、水的部分激发和Cho、Cre和NAA的激发。使用重复的螺旋k空间轨迹对平面内空间和光谱信息（kx，ky，kf）进行编码。使用标准相位编码进行z方向（kz）上的编码。然后将每个体素和线圈的相位谱组合，通过水信号加权，以实现最大SNR。生成每个体素的Cho、Cr和NAA浓度以及Cho和NAA与Cr的浓度比。 招募8名受试者进行再现性研究。7名受试者各扫描1次，1名受试者扫描6次。在高分辨率结构图像上绘制感兴趣区域，包括额叶、顶叶、颞叶和枕叶以及基底节和丘脑。通过对来自每个ROI内的所有体素的信号进行平均来获得最终代谢物值。 5个ROI的受试者间CV范围为NAA/Cr的6.1-11%和Cho/Cr的7.2-12.1%。5个ROI的受试者内CV范围为NAA/Cr的4.7-12.7%和Cho/Cr的2.7-7.1%。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Introduction: Brain H-MRSI has become an important clinical tool Although widely used, most brain MRSI sequences suffer from drawbacks including limited spatial coverage, insufficient water and lipid suppression, long scan times, low SNR and lack of robust automated spectral quantification. To address these limitations, we implemented a fast 3D whole-brain 1.5T MRSI sequence with efficient and robust water and lipid suppression, spiral k-space readout trajectories, and an 8-channel phased-array coil. In this work, we assessed the reliability and reproducibility of the sequence and the data processing methods. Methods and Discussion: A spectral-spatial 90 degree RF pulse and two identical dualband spectral-spatial 180 degree pulses were incorporated into a PRESS sequence for localization, partial excitation of water and excitation of Cho, Cre and NAA. In-plane spatial and spectral information (kx, ky,kf ) was encoded using repeated spiral k-space trajectories. Encoding in z direction (kz) was performed using standard phase encoding. Phased spectra for each voxel and coil were then combined, weighted by water signal, to achieve maximum SNR. Concentrations of Cho, Cr and NAA and concentrations ratios of Cho and NAA to Cr were generated for each voxel. Eight subjects were recruited for a reproducibility study. Seven subjects were each scanned once while one subject was scanned 6 times. Regions of interest covering the frontal, parietal, temporal, and occipital lobes and basal ganglia and thalamus, were drawn on the high-resolution structural images. Final metabolite values were obtained by averaging signals from all voxels within each ROI. The inter-subject CVs of the five ROIs ranged from 6.1-11% for NAA/Cr and 7.2-12.1% for Cho/Cr. The intra-subject CVs of five ROIs ranged from 4.7-12.7% for NAA/Cr and 2.7-7.1% for Cho/Cr.