Brain damage from perinatal asphyxia: correlation of MR findings with gestational age.

MR scans of 25 patients who suffered asphyxia at known gestational ages were reviewed retrospectively. The gestational ages of the patients at the time of asphyxia ranged from 24 to 46 weeks. The MR pattern of brain damage in patients with prolonged partial asphyxia was seen to evolve in a predictable manner corresponding to the known maturation of the brain and its vascular supply. Patients at 24- and 26-weeks gestational age had irregularly enlarged ventricular trigones with minimal periventricular gliosis. Patients at 28-34 weeks had variably dilated ventricles with periventricular gliosis. The 36-week neonate had mild cortical and subcortical atrophy and gliosis superimposed on deep white matter and periventricular gliosis. Term neonates had significant cortical and subcortical gliosis and atrophy in the parasagittal watershed areas. Postterm neonates (44-46 weeks) showed cortical and subcortical watershed gliosis and atrophy with sparing of the immediate periventricular region. Two children suffered cardiocirculatory arrest; their scans revealed a different pattern of brain damage, demonstrating primarily brainstem, thalamic, and basal ganglia involvement. MR appears to be a powerful tool in the assessment of brain damage resulting from perinatal asphyxia that gives important clues to the time and nature of the asphyxia.