Jensen J Eric, Auerbach Randy P, Pisoni Angela, Pizzagalli Diego A
McLean Imaging Center, McLean Hospital, Belmont, MA, USA.
Harvard Medical School, Boston, MA, USA.
NMR Biomed. 2017 Nov;30(11). doi: 10.1002/nbm.3771. Epub 2017 Jul 21.
Glutamate is the prime excitatory neurotransmitter in the mammalian brain and has been implicated in a wide range of psychiatric conditions. To improve the applicability and clinical reach of magnetic resonance spectroscopy (MRS), research is needed to develop shortened, yet reliable, MRS scanning procedures for standard 1.5-3-T clinical magnetic resonance imaging (MRI) systems, particularly with young or vulnerable populations unable to tolerate longer protocols. To this end, we evaluated the test-retest reliability of a shortened J-resolved MRS sequence in healthy adolescents (n = 22) aged 12-14 years. Participants underwent a series of sequential 6-min MRS scans, with the participants remaining in situ between successive scans. Glutamate and other metabolites were acquired from the rostral anterior cingulate cortex, as glutamatergic function in this region has been implicated in a number of psychiatric illnesses. Thirteen neurochemicals were quantified as ratios to total creatine, and reliability scores were expressed as the percentage difference between the two scans for each metabolite. Test-retest assessment of glutamate was reliable, as scores were less than 10% different (7.1 ± 4.2%), and glutamate values across scans were significantly correlated (Pearson r = 0.680, p < 10 ). Several other neurochemicals demonstrated satisfactory reliability, including choline (Cho) (7.4 ± 5.6%), glutathione (GSH) (8.6 ± 4.1%), myo-inositol (mI) (6.5 ± 7.1%) and N-acetylaspartate (NAA) (3.5 ± 3.6%), with test-retest correlations ranging from 0.747 to 0.953. A number of metabolites, however, did not demonstrate acceptable test-retest reliability using the current J-resolved MRS sequence, ranging from 13.8 ± 13.7% (aspartate, Asp) to 45.9 ± 38.3% (glycine, Gly). Collectively, test-retest analyses suggest that clinically viable quantitative data can be obtained on standard MRI systems for glutamate, as well as the other metabolites, during short scan times in a traditionally challenging brain region.
谷氨酸是哺乳动物大脑中主要的兴奋性神经递质，与多种精神疾病有关。为了提高磁共振波谱（MRS）的适用性和临床应用范围，需要开展研究以开发缩短但可靠的MRS扫描程序，用于标准的1.5 - 3T临床磁共振成像（MRI）系统，特别是针对无法耐受较长扫描方案的年轻或脆弱人群。为此，我们评估了缩短的J分辨MRS序列在12至14岁健康青少年（n = 22）中的重测可靠性。参与者接受了一系列连续的6分钟MRS扫描，在连续扫描之间保持原位。从喙部前扣带回皮质获取谷氨酸和其他代谢物，因为该区域的谷氨酸能功能与多种精神疾病有关。将13种神经化学物质定量为与总肌酸的比率，可靠性分数表示为每次扫描中每种代谢物两次扫描之间的百分比差异。谷氨酸的重测评估是可靠的，因为分数差异小于10%（7.1±4.2%），并且扫描间的谷氨酸值显著相关（Pearson r = 0.680，p < 0.01）。其他几种神经化学物质也显示出令人满意的可靠性，包括胆碱（Cho）（7.4±5.6%）、谷胱甘肽（GSH）（8.6±4.1%）、肌醇（mI）（6.5±7.1%）和N - 乙酰天门冬氨酸（NAA）（3.5±3.6%），重测相关性范围为0.747至0.953。然而，使用当前的J分辨MRS序列，一些代谢物并未显示出可接受的重测可靠性，范围从13.8±13.7%（天冬氨酸，Asp）到45.9±38.3%（甘氨酸，Gly）。总体而言，重测分析表明，在传统上具有挑战性的脑区进行短时间扫描时，可在标准MRI系统上获得关于谷氨酸以及其他代谢物的临床可行定量数据。
