Proton spectroscopy and diffusion imaging on the first day of life after perinatal asphyxia: Preliminary report

BACKGROUND AND PURPOSE: MR techniques have proved useful in assessing brain injury from perinatal asphyxia when the injury is subacute or chronic. Rec ent advances in understanding the molecular mechanisms of brain injury have made medical intervention plausible, creating a need for assessment of the brain within the first few hours of life. We report the results of early ( first 24 hours after birth) MR imaging in seven patients, including proton MR spectroscopy in six. METHODS: MR studies were performed within the first 24 hours of life in sev en consecutive patients who were encephalopathic after complicated deliveri es. Standard T1-, T2-, and diffusion-weighted sequences were performed in a ll patients; single-voxel MR spectroscopy was performed in two locations in six of the seven patients. Follow-up MR studies were performed in four pat ients at ages 7, 8, 9, and 15 days, respectively. RESULTS: T1-weighted images were normal in all seven patients. T2-weighted images were normal in three patients and showed T2 prolongation in the basa l ganglia or white matter in the other four. Diffusion images showed small abnormalities in the lateral thalami or internal capsules in all seven pati ents. Comparison with clinical course in all seven patients and with follow -up MR studies in four showed that the diffusion images underestimated the extent of brain injury. Proton MR spectroscopy showed substantial lactate e levation in all six of the patients studied. Two patients died in the neona tal period and the other five were left with clinically significant neurolo gic impairment. CONCLUSION: MR spectroscopy performed in the first 24 hours after birth is sensitive to the presence of hypoxic-ischemic brain injury, whereas diffusi on imaging may help identify but underestimate the extent of the injury. Fu rther studies are ongoing in an attempt to expand upon this observation.