Quantitative analysis of brain metabolites concentrations using MR spectroscopy in acute hypoxia ischemic encephalopathy / 中华放射学杂志

ABSTRACT

Objective To evaluate the absolute quantification of brain metabolites concentrations using external standard MRS in acute hypoxia ischemia encephalopathy (HIE) piglet model. Method Eight 7-day-old healthy piglets were subjected to insult of hypoxia ischemia (HI). The animals and an external standard phantom containing detectable metabolites of known concentrations were studied on a 1.5 T GE Signa scanner. The single-voxel proton magnetic resonance spectroscopy (1H-MRS) data were processed using LCModel software, and the quantification of N-acetylaspartate ( NAA), creatine (Cr) and lactate (Lac) were accomplished. Multivariate analysis of variance was performed to compare the NAA, Cr, Lac concentration differences in the brains of piglets pre- and post-HI (0h). In addition, the dynamic changes of brain metabolites concentrations of 2 HIE piglets were observed at the time points of 0 h and 2 h. Results One piglet was excluded because it was over anesthetized to death. Seven piglets' data were analyzed. The concentrations of NAA pre- and post-HI were ( 6. 86 ± 0. 49 ) mmol/kg and ( 5.73 ± 0. 88 ) mmol/kg respectively, they were ( 4. 65 ± 0. 73 ) mmol/kg and ( 4. 40 ± 0. 80 ) mmol/kg for Cr; and were 0. 00 mmol/kg and (0. 43 ± 0. 39) mmol/kg for Lac. After HI, decreased NAA concentration immediately was observed, and it was of statistical significance ( F = 8. 608, P = 0. 013 ). The concentration of Cr was insignificantly decreased ( F = 0. 379, P = 0. 550). The concentration of Lac was increased, and the difference was of statistical significance ( F = 8. 600 ,P = 0. 013 ). Dynamic observation showed a Lac peak immediately after HI and it decreased after 2 h post-HI. Conclusions External standard MRS using LCModel has great value in the quantitative analysis of brain metabolites. The changes of NAA and Lac concentrations are sensitive to reflect the early metabolic change of acute HIE.