Proton MR spectroscopy in infants with cerebral energy deficiency due to hypoxia and metabolic disorders.

OBJECTIVE

To investigate the similarities and differences of cellular energy deficiencies due to asphyxia and to impaired oxidative phosphorylation caused by enzyme deficiencies using localized 1H-MR spectroscopy of the brain.

METHODS

In 35 neonates and infants with a postconceptional age of 36.4-153 weeks, 1H-MR spectra were obtained from the basal ganglia. Of the 35 children, 14 served as a control group, 12 suffered from hypoxic-ischemic disease (HIE), and 9 had congenital enzymatic disorders.

RESULTS

Eleven of the 12 children with HIE showed low N-acetyl aspartate (NAA) to trimethylamine (TMA) ratios, indicating neuronal damage. Lactate (Lac) to TMA ratios correlated with the HIE grade. Children with congenital disorders of energy metabolism had NAA/TMA ratios ranging from severely decreased to normal, but 7 of the 9 had high Lac signals, even in brains with normal NAA/TMA.

CONCLUSIONS

High Lac/TMA even with normal NAA/TMA in children with enzyme deficiencies, in contrast to Lac/TMA that correlates with clinical grade and low NAA/TMA in asphyxic children, hints at different mechanisms of cell damage in the two disease groups.