The effect of whole-body cooling on brain metabolism following perinatal hypoxic–ischemic injury

Abstract

ArticlesClinical Investigation nature publishing group INTRODUCTION: Magnetic resonance imaging (MRI) and spectroscopy (MRs) have proven valuable in evaluating neonatal hypoxic-ischemic injury (hII). RESULTS: MRI scores in the basal ganglia of hII/hT + neonates were significantly lower than hII/hT − neonates, indicating less severe injury and were associated with lower discharge encephalopathy severity scores in the hII/hT + group (P = 0.01). Lactate (Lac) was detected in the occipital gray matter (OGM) and thalamus (Th) of significantly more hII/hT − neonates (31.6 and 35.3%) as compared to the hII/hT + group (10.5 and 15.8%). In contrast, the N-acetylaspartate (Naa)-based ratios in the OGM and Th did not differ between the hII groups. DISCUSSION: Our data show that the hT was associated with a decrease in the number of hII neonates with detectable cortical and subcortical Lac as well as a decrease in the number of MRI-detectable subcortical lesions. METHODS:We retrospectively compared the medical and neuroimaging data of 19 hII neonates who received 72 h of wholebody cooling (hII/hT + ) with those of 19 noncooled hII neonates (hII/hT − ) to determine whether hypothermia was associated with improved recovery from the injury as measured by MRI and MRs within the first 14 days of life. MRI scores and metabolite ratios of hII/hT + and hII/hT − neonates were also compared with nine healthy, nonasphyxiated "control" neonates.

Brain imaging in cooled encephalopathic neonates does not differ between four and 11 days after birth

“…Magnetic Resonance Imaging studies suggest that TH mainly reduces cortical grey matter and BGT lesions (7,8,11,12,(16)(17)(18). However, the optimal timing for seeing MRI lesions and for predicting outcome after TH is still unclear.…”

“…Conventional MRI has a high sensitivity for detecting hypoxic-ischaemic brain injury, and there is a strong association between MRI findings and neurodevelopmental outcome (5,6). Several studies have shown a decreased lesion load in HIE after TH (7,8,11,12). Conventional MRI and diffusion-weighted imaging findings evolve considerably in the first postinsult days (9,10), and very early imaging may underestimate the final extent of brain damage.…”

Neuroprotective Treatments after Perinatal Hypoxic-Ischemic Brain Injury Evaluated with Magnetic Resonance Spectroscopy

“…Changes in NAA concentrations evolve more slowly, and preserved NAA levels with hypothermia have been shown by 1 H MRS performed within 2 weeks after birth [31] . Better preserved Lac/NAA or NAA/Cr ratios are associated with a better clinical encephalopathy severity score and an improved brain microstructure [30,31] . Since TH affects cerebral metabolism, it might alter the prognostic accuracy of 1 H MRS for the long-term outcome.…”

“…Lac levels in asphyxiated infants are reduced during hypothermia [29] , shortly after rewarming [30] , and in the subacute phase [31,32] . This may reflect the neuroprotective effect of hypothermia on mitochondria in the early phase after HI as well as its potential anti-inflammatory effects during the subacute phase (increased Lac levels at this time point are likely to be related to the presence of brain macrophages [microglia] [33,34] ).…”

Identifying premature infants at high and low risk for motor delays using motor performance testing and MRS

“…For MRS metabolites, developmental changes are well described: NAA increases, while mI decreases with increasing GA at scan. But gestational age at birth and post-natal age may also affect the outcome of a scan done at term age [33][34][35][36]. Gestational age at birth may be important if subsequent development of the brain region depends heavily on the stage at which the infant was exposed to the extrauterine environment, or if brain injury occurs near the time of birth [37].…”