Hypoxia-ischemic encephalopathy in full-term neonate: correlation proton MR spectroscopy with MR imaging.

INTRODUCTION: To evaluate 1H Magnetic Resonance Spectroscopy (1HMRS) in the diagnosis of hypoxia-ischemic encephalopathy (HIE) of full-term neonates correlated with Magnetic Resonance Imaging (MRI).
MATERIALS AND METHODS: Thirty-eight cases of full-term neonates diagnosed as HIE clinically were selected to perform MRI and 1HMRS examination. The ages ranged from 7 to 17 days, with median age of 8.2 days. In which, 26 cases were followed up and/or MRI reexamined at 6 months of age or later. Eight healthy neonates, with no evidence of birth asphyxia, also underwent 1HMRS for comparison. SE sequences were used for routine MR examination; point resolved spectroscopy sequence was required for 1HMRS. The metabolites in the spectra includes: N-acetylaspartate (NAA), choline compounds (CHO), creatine compounds (CR), myo-inositol (MI), lactate (LAC), glutamate and glutamine (Glu-Gln).
RESULTS: The peaks of NAA were fall in two cases; the peaks of LAC, which were elevated, appeared as typical double-peaks appearance in 26 cases; the peaks of Glu-Gln, which were also elevated, appeared as zigzag appearance in nine cases. The peaks of CR were decreased in 11 cases, while those of MI were increased in seven cases. Mild type of lesions was present on MRI in 12 cases whose LAC/CR ratio lower than 0.5; mild and moderate types of lesions were present in 15 cases whose LAC/CR ratio between 0.5 and 1.5. Whereas, nine cases of severe lesions and two cases of moderate lesions were present on MRI in 11 cases whose LAC/CR ratio greater than 1.5. Twenty-six of 38 cases were followed up and/or MRI reexamined after 6 months, in which, sequelae were present in 12 cases. Among them, eight cases of sequelae in nine cases whose LAC/CR ratio greater than 1.5 were present (account for 88.89%).
CONCLUSION: 1HMRS plays an important role to diagnose and predict outcome of HIE.