Brain γ-aminobutyric acid (GABA) detection in vivo with the J-editing (1) H MRS technique: a comprehensive methodological evaluation of sensitivity enhancement, macromolecule contamination and test-retest reliability.
Brain γ-aminobutyric acid (GABA) detection in vivo with the J-editing (1) H MRS technique: a comprehensive methodological evaluation of sensitivity enhancement, macromolecule contamination and test-retest reliability.
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DOI：
10.1002/nbm.3539
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发表时间：
2016-07
影响因子：
2.9
通讯作者：
Kegeles LS
中科院分区：
文献类型：
--
作者：
Shungu DC;Mao X;Gonzales R;Soones TN;Dyke JP;van der Veen JW;Kegeles LS
脑γ-氨基丁酸（GABA）异常与各种神经精神和神经疾病有关。然而，质子磁共振波谱（1H MRS）在体内检测GABA面临着巨大的挑战，包括低脑浓度、强共振的重叠以及移动大分子（MM）信号的污染。本研究通过(a)评估使用8通道相控阵头线圈可获得的灵敏度增益，(b)确定MM对GABA污染的大小和解剖变异，以及(c)估计使用该方法测量GABA的重测可靠性，解决了在健康人类3T MR系统上使用j编辑差分技术进行可靠脑GABA检测的这些障碍。在背外侧前额皮质（DLPFC）中检测了灵敏度增益和重测可靠性，同时比较了三个皮质区域的MM水平：DLPFC、内侧前额皮质（MPFC）和枕皮质（OCC）。与DLPFC中的标准单通道头线圈相比，8通道头线圈的GABA检测灵敏度提高了3倍。尽管GABA+MM和MM在三个脑区有显著的解剖差异（p < 0.05），但MM对GABA+MM的贡献在三个体素中相对稳定，在41%至49%之间，区域差异不显著（p = 0.58）。用体素组织水(W)或总肌酸的比值表示的GABA测量的测试-重测可靠性被发现对于单通道线圈和8通道相控阵线圈都非常高。以8通道线圈为例，GABA/W检验与复验的Pearson相关系数为0.98 (R2 = 0.96, p = 0.0007)，变异百分率系数（CV）为1.25%，类内相关系数（ICC）为0.98。相似的可靠性也被发现用于两个线圈的联合谷氨酸和谷氨酰胺（Glx）的共同编辑共振。
Abnormalities in brain γ-aminobutyric acid (GABA) have been implicated in various neuropsychiatric and neurological disorders. However, in vivo GABA detection by proton magnetic resonance spectroscopy (1H MRS) presents significant challenges arising from low brain concentration, overlap by much stronger resonances, and contamination by mobile macromolecule (MM) signals. This study addresses these impediments to reliable brain GABA detection with the J-editing difference technique on a 3T MR system in healthy human subjects by (a) assessing the sensitivity gains attainable with an 8-channel phased-array head coil, (b) determining the magnitude and anatomic variation of the contamination of GABA by MM, and (c) estimating the test-retest reliability of measuring GABA with this method. Sensitivity gains and test-retest reliability were examined in the dorsolateral prefrontal cortex (DLPFC), while MM levels were compared across three cortical regions: the DLPFC, the medial prefrontal cortex (MPFC) and the occipital cortex (OCC). A 3-fold higher GABA detection sensitivity was attained with the 8-channel head coil compared to the standard single-channel head coil in DLPFC. Despite significant anatomic variation in GABA+MM and MM across the three brain regions (p < 0.05), the contribution of MM to GABA+MM was relatively stable across the three voxels, ranging from 41% to 49%, a non-significant regional variation (p = 0.58). The test-retest reliability of GABA measurement, expressed either as ratios to voxel tissue water (W) or total creatine, was found to be very high for both the single-channel coil and the 8-channel phased-array coil. For the 8-channel coil, for example, Pearson’s correlation coefficient of test vs. retest for GABA/W was 0.98 (R2 = 0.96, p = 0.0007), the percent coefficient of variation (CV) was 1.25%, and the intraclass correlation coefficient (ICC) was 0.98. Similar reliability was also found for the co-edited resonance of combined glutamate and glutamine (Glx) for both coils.