Feasibility and reproducibility of neurochemical profile quantification in the human hippocampus at 3T
Feasibility and reproducibility of neurochemical profile quantification in the human hippocampus at 3T
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DOI：
10.1002/nbm.3309
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发表时间：
2015-06-01
影响因子：
2.9
通讯作者：
Oez, Guelin
中科院分区：
文献类型：
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作者：
Bednarik, Petr;Moheet, Amir;Oez, Guelin
众所周知，海马体功能障碍与几种神经和神经精神疾病有关，如阿尔茨海默病、癫痫、精神分裂症和抑郁症；因此，研究海马神经化学具有重要的临床意义。然而，使用H-1 MRS研究海马是一个具有挑战性的区域，因此MRS用于该区域的临床研究受到限制。因此，我们的目标是研究获得高质量海马光谱的可行性，从而可以可靠地量化神经化学谱，并建立海马MRS的会话间再现性，包括体素位置、光谱质量和神经化学浓度的再现性。10名健康志愿者在连续两个疗程中使用标准的临床3T磁共振扫描仪进行扫描。从t- 1加权图像分割计算的相对较小的体素（类似于4mL）覆盖约62%的海马体积，通过短回声（T-E=28ms）半激光定位序列获得神经化学谱。体素组成具有高度重复性，灰质和白质体积分数的重测变异系数（cv）分别为3.5%和7.5%。在所有受试者中均获得了良好的信噪比（基于n-乙酰天冬氨酸（NAA）甲基峰的非离化光谱近似于54）和线宽（近似于水的9Hz）。光谱质量允许定量NAA、总胆碱、总肌酸、肌醇和谷氨酸，具有高扫描扫描重现性（CV6%）和定量精度（Cramer-Rao下限，CRLB）
Hippocampal dysfunction is known to be associated with several neurological and neuropsychiatric disorders such as Alzheimer's disease, epilepsy, schizophrenia and depression; therefore, there has been significant clinical interest in studying hippocampal neurochemistry. However, the hippocampus is a challenging region to study using H-1 MRS, hence the use of MRS for clinical research in this region has been limited. Our goal was therefore to investigate the feasibility of obtaining high-quality hippocampal spectra that allow reliable quantification of a neurochemical profile and to establish inter-session reproducibility of hippocampal MRS, including reproducibility of voxel placement, spectral quality and neurochemical concentrations. Ten healthy volunteers were scanned in two consecutive sessions using a standard clinical 3T MR scanner. Neurochemical profiles were obtained with a short-echo (T-E=28ms) semi-LASER localization sequence from a relatively small (similar to 4mL) voxel that covered about 62% of the hippocampal volume as calculated from segmentation of T-1-weighted images. Voxel composition was highly reproducible between sessions, with test-retest coefficients of variation (CVs) of 3.5% and 7.5% for gray and white matter volume fraction, respectively. Excellent signal-to-noise ratio (similar to 54 based on the N-acetylaspartate (NAA) methyl peak in non-apodized spectra) and linewidths (similar to 9Hz for water) were achieved reproducibly in all subjects. The spectral quality allowed quantification of NAA, total choline, total creatine, myo-inositol and glutamate with high scan-rescan reproducibility (CV6%) and quantification precision (Cramer-Rao lower bound, CRLB