Postasphyxial encephalopathy in full-term infants: ultrasound diagnosis.

Abnormal cranial ultrasound findings are described in 18 infants with severe asphyxia. The examinations performed within the first 7 days after the asphyxial episode frequently showed obliteration of the ventricles and extra-axial fluid spaces with mildly increased cerebral echogenicity, presumably representing cerebral edema. Others showed diffusely abnormal parenchymal echogenicity with normal ventricles and sulci. Ultrasound findings seen after the first week of life included increased size of the ventricles and extra-axial fluid, the result of cerebral atrophy. The sensitivity, specificity, and accuracy of both early and late abnormal ultrasonograms were calculated for predicting an abnormal neurological outcome. While the sensitivity of the abnormal early (performed within 7 days of birth) ultrasonogram was relatively low (46%), the sensitivity of an abnormal late (performed after 7 days) ultrasonogram was high (86%). The specificity for both abnormal early and late ultrasound was 100%. These findings suggest that cranial ultrasonography can be used as a screening procedure to provide information about the neurologic outcome to clinicians caring for these infants.