MRI lesions and infants with neonatal encephalopathy. Is the Apgar score predictive?

The aim of this study was to establish whether, in full-term infants presenting with neonatal encephalopathy, the 1 minute Apgar score gives an indication of the presence, site or type of lesions observed on brain MRI in the neonatal period.

The study cohort included 157 full-term infants who had neurological abnormalities during the first 48 hours after delivery. Infants with developmental, genetic, infective or metabolic diagnoses were excluded from the study. The infants were subdivided according to their 1 minute Apgar score into three groups as follows: Apgar score 0 - 3 (n = 108/157, 69 %), 4 - 7 (n = 29, 19 %), 8 - 10 (n = 21, 12 %). Results. Severe and moderate basal ganglia and thalamic (BGT) lesions, with one exception, were only observed in the group with an Apgar score of 3 or below. Minimal BGT lesions were, with one exception, associated with scores below 7 and mainly below 3. However, not all the infants with low Apgar scores had BGT lesions and 28 % of the patients with Apgar scores below 3 had normal scans or only minimal white matter changes. White matter lesions without BGT involvement were equally distributed in the cohort, irrespective of the Apgar scores. Cerebral infarction and scattered white matter haemorrhages were the most common findings in infants with Apgar scores of 4 and above. The Apgar scores were not always predictive of motor outcome at 2 years but the presence and severity of the sequelae mainly reflected the site and severity of MRI findings.

These findings stress the importance of subdividing neonatal encephalopathy into diagnostic categories according to brain lesions if one wishes to study either causative factors or outcome.