Temporal brain metabolite changes in preterm infants with normal development

Objective: Preterm infants are at high risk for developmental delay, epilepsy, and autism spectrum disorders. Some reports have described associations between these conditions and gamma-aminobutyric acid (GABA) dysfunction; however, no study has evaluated temporal changes in GABA in preterm infants. Therefore, we assessed temporal changes in brain metabolites including GABA using single-voxel 3-Tesla (T) proton magnetic resonance spectroscopy (H-1-MRS) in preterm infants with normal development. Methods: We performed 3T H-1-MRS at 37-46 postmenstrual weeks (PMWs, period A) and 64-73 PMWs (period B). GABA was assessed with the MEGA-PRESS method. N-acetyl aspartate (NAA), glutamate-glutamine complex (Glx), creatine (Cr), choline (Cho), and myo-inositol (Ins) were assessed with the PRESS method. Metabolite concentrations were automatically calculated using LCModel. Results: Data were collected from 20 preterm infants for periods A and B (medians [ranges], 30 [24-34] gestational weeks, 1281 [486-2030] g birth weight). GABA/Cr ratio decreased significantly in period B (p = 0.03), but there was no significant difference in GABA/Cho ratios (p = 0.58) between the two periods. In period B, NAA/Cr, Glx/Cr, NAA/Cho, and Glx/Cho ratios were significantly increased (p < 0.01), whereas Cho/Cr, Ins/Cr, and Ins/Cho ratios were significantly decreased (p < 0.01). There was no significant difference for GABA or Cho concentrations (p = 0.52, p = 0.22, respectively). NAA, Glx, and Cr concentrations were significantly increased (p < 0.01), whereas Ins was significantly decreased (p < 0.01). Conclusions: Our results provide new information on normative values of brain metabolites in preterm infants. (C) 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.