Brain metabolite concentrations are associated with illness severity scores and white matter abnormalities in very preterm infants

BACKGROUND: Magnetic resonance spectroscopy allows for the noninvasive study of brain metabolism and therefore may provide useful information about brain injuries. We examined the associations of brain metabolite ratios in very preterm infants with white matter lesions and overall health status at birth. METHODS: Spectroscopy data were obtained from 99 very preterm infants (born ≤32wk gestation) imaged shortly after birth and from 67 of these infants at term-equivalent age. These data were processed using LC Model. Multiple regression was used to examine the association of metabolite ratios with focal non cystic white matter lesions visible on conventional magnetic resonance imaging (MRI) and with at-birth illness severity scores. RESULTS: Within 2wk of birth, the ratio of N-acetylaspartate + N-acetylaspartylglutamate to creatine + phosphocreatine was significantly lower in those infants showing white matter abnormalities on conventional MRI. Increased lactate to creatine + phosphocreatine and lactate to glycerophosphocholine + phosphocholine ratios were significantly associated with increasing severity of Clinical Risk Index for Babies II and Apgar scores taken at 1 and 5min after birth. CONCLUSION: Both overall health status at birth and white matter injury in preterm neonates are reflected in metabolite ratios measured shortly after birth. Long-term follow-up will provide additional insight into the prognostic value of these measures.