Increased detectability of alpha brain glutamate/glutamine in neonatal hypoxic-ischemic encephalopathy.
OBJECTIVE
Proton MR spectroscopy (MRS) detectability of brain glutamate/glutamine (Glx) is increased in hypoxic-ischemic insults and is implicated in the neuronal injury and death that follows. Our aim was to correlate the proton MRS detectability of alpha-CH protons of Glx (alpha-Glx) with the Sarnat stage of neonatal hypoxic-ischemic encephalopathy (HIE).


METHODS
Initial and follow-up proton MRS studies at 1.9 T were performed in 28 neonates aged 1 to 7 days (seven healthy control subjects and 21 with HIE: 10 mild, nine moderate, and two severe) and in 12 neonates aged 13 to 17 days (12 with HIE: eight mild, three moderate, and one severe), respectively. Both point-resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) sequences were used. The spectral volume of interest was in the basal ganglia, thalami, and adjoining regions. The detectability of alpha-Glx was assessed by two different parameters: the detection rate of the alpha-Glx peak and the peak-area ratio of alpha-Glx to creatine and phosphocreatine.


RESULTS
On both the initial and follow-up PRESS studies, all the neonates with moderate and severe HIE showed an alpha-Glx peak, compared with one healthy control subject in the initial study and one neonate with mild HIE in both the studies. They also demonstrated a significantly higher peak-area ratio of alpha-Glx/(creatine and phosphocreatine) on both the initial and follow-up studies. The peak-area ratios in neonates with HIE positively correlated with the Sarnat stage of HIE on both the initial and follow-up studies. Neonates with moderate and severe HIE also showed a consistently higher alpha-Glx peak on both the initial and follow-up studies with the STEAM sequence.


CONCLUSIONS
Proton MRS detectability of alpha-Glx is increased in moderate and severe HIE and correlates with the Sarnat stage of HIE.
Pu
Y
Y
The People's Hospital of The Beijing Medical University, The People's Republic of China.
Li
Q F
QF
Zeng
C M
CM
Gao
J
J
Qi
J
J
Luo
D X
DX
Mahankali
S
S
Fox
P T
PT
Gao
J H
JH
D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism*; D005500:Follow-Up Studies; D018698:Glutamic Acid / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism*; D006801:Humans; D002534:Hypoxia, Brain / Q000378:metabolism*; D007231:Infant, Newborn; D009682:Magnetic Resonance Spectroscopy
D005973:Glutamine; D018698:Glutamic Acid