An Increase in Cerebral γ-Amino Butyric Acid Concentration in Children with Mild Traumatic Brain Injury in the Acute Phase: 1H MRS Study

Abstract

In this study, the concentrations of major inhibitory (γ-amino butyric acid) and excitatory (glutamate) neurotransmitters have been estimated for the first time in the norman appearing brain tissue in children with mild traumatic brain injury using magnetic resonance and computer tomography data. ¹H magnetic resonance spectra were processed with the J-difference editing technique. It was shown that after mild traumatic brain injury, the concentration of γ-amino butyric acid increases (by 36%) in the frontal lobes, that shifts the inhibitory/excitatory (γ-amino butyric acid/glutamate) balance. It is found that using standart MEGA-PRESS pulse sequence for γ-amino butyric concentration quantification leads to masking the effect of γ-amino butyric acid alteration because the collected signal consists of the signals produced from protons of γ-methylene group of the γ-amino butyric acid and signals from protons of mobile amino-acid chains of proteins. Therefore, a pulse sequence should be modified with symmetrical suppression of signals from mobile amino-acid chains of proteins.