From the Department of Neonatology (S.K.B.).
Developing Brain Institute (S.K.B., S.P., S.D.B., K.J.K., J.L.Q., C.A.L., C.L.).
AJNR Am J Neuroradiol. 2022 Jan;43(1):125-131. doi: 10.3174/ajnr.A7336. Epub 2021 Nov 11.
Gamma-aminobutyric acid and glutamate system disruptions may underlie neonatal brain injury. However, in vivo investigations are challenged by the need for special H-MR spectroscopy sequences for the reliable measurement of the neurotransmitters in this population. We used -edited H-MR spectroscopy (Mescher-Garwood point-resolved spectroscopy) to quantify regional in vivo gamma-aminobutyric acid and glutamate concentrations during the early postnatal period in healthy neonates.
We prospectively enrolled healthy neonates and acquired Mescher-Garwood point-resolved spectroscopy spectra on a 3T MR imaging scanner from voxels located in the cerebellum, the right basal ganglia, and the right frontal lobe. CSF-corrected metabolite concentrations were compared for regional variations and cross-sectional temporal trends with advancing age.
Fifty-eight neonates with acceptable spectra acquired at postmenstrual age of 39.1 (SD, 1.3) weeks were included for analysis. Gamma-aminobutyric acid (+ macromolecule) (2.56 [SD, 0.1]) i.u., glutamate (3.80 [SD, 0.2]), Cho, and mIns concentrations were highest in the cerebellum, whereas NAA (6.72 [SD, 0.2]), NAA/Cho, Cr/Cho, and Glx/Cho were highest in the basal ganglia. Frontal gamma-aminobutyric acid (1.63 [SD, 0.1]), Glx (4.33 [SD, 0.3]), Cr (3.64 [SD, 0.2]), and Cho concentrations were the lowest among the ROIs. Glx, NAA, and Cr demonstrated a significant adjusted increase with postmenstrual age (β = 0.2-0.35), whereas gamma-aminobutyric acid and Cho did not.
We report normative regional variations and temporal trends of in vivo gamma-aminobutyric acid and glutamate concentrations reflecting the functional and maturational status of 3 distinct brain regions of the neonate. These measures will serve as important normative values to allow early detection of subtle neurometabolic alterations in high-risk neonates.
γ-氨基丁酸和谷氨酸系统的紊乱可能是新生儿脑损伤的基础。然而，由于需要特殊的 H-MR 波谱序列来可靠地测量该人群中的神经递质，因此体内研究受到了挑战。我们使用-edited H-MR 波谱（Mescher-Garwood 点分辨波谱）来定量测量健康新生儿出生后早期的脑内γ-氨基丁酸和谷氨酸浓度。
我们前瞻性纳入健康新生儿，在 3T MR 成像扫描仪上从位于小脑、右侧基底节和右侧额叶的体素采集 Mescher-Garwood 点分辨波谱。比较 CSF 校正的代谢物浓度，以了解区域变化和随年龄增长的横断面时间趋势。
纳入 58 例胎龄为 39.1（标准差，1.3）周的可接受谱的新生儿进行分析。小脑内γ-氨基丁酸（+大分子）（2.56[标准差，0.1]）i.u.、谷氨酸（3.80[标准差，0.2]）、Cho 和 mIns 浓度最高，而 NAA（6.72[标准差，0.2]）、NAA/Cho、Cr/Cho 和 Glx/Cho 浓度在基底节中最高。额叶γ-氨基丁酸（1.63[标准差，0.1]）、Glx（4.33[标准差，0.3]）、Cr（3.64[标准差，0.2]）和 Cho 浓度在 ROI 中最低。Glx、NAA 和 Cr 经调整后随胎龄呈显著增加（β=0.2-0.35），而γ-氨基丁酸和 Cho 则不然。
我们报告了体内γ-氨基丁酸和谷氨酸浓度的正常区域变化和时间趋势，反映了新生儿 3 个不同脑区的功能和成熟状态。这些测量值将作为重要的正常值，以允许早期发现高危新生儿的微妙神经代谢改变。
