Hypoxic-ischemic encephalopathy: Correlation of serial MRI and outcome
Introduction
Neonatal asphyxia causing hypoxic-ischemic encephalopathy frequently results in the chronic handicapping conditions of cerebral palsy, mental retardation, learning disability, epilepsy, behavioral problems, intellectual deficits, and mortality [1]. The stage of encephalopathy was suggested as the main predictor of outcome in perinatal asphyxia. However, follow-up studies have demonstrated that the outcome cannot be always predicted by the severity of hypoxic-ischemic encephalopathy [2]. One way to establish brain injury in asphyxiated children is to use neuroimaging methods. Magnetic resonance imaging has been demonstrated to be a useful tool for evaluation of brain damage in asphyxiated infants. Because of higher sensitivity and specificity to maturational changes such as evaluation of myelination, magnetic resonance imaging has had an enormous impact on neurologic imaging. Especially serial imaging can identify specific patterns of injury accurately [3], [4]. Several studies have tried to establish the predictive value of magnetic resonance imaging in children with perinatal asphyxia [5], [6], [7], [8], [9], [10]. There are few reports that document serial magnetic resonance imaging findings in infants with hypoxic-ischemic encephalopathy in association with long-term neurologic assessment [11], [12], [13]. Neurologic outcome was determined usually at 12-24 months of age in these studies. However, cerebral palsy may not be accurately diagnosed until 3 to 4 years of age.
This study aimed to evaluate the role of serial magnetic resonance imaging examinations in predicting late neurodevelopmental outcome, and to describe the characteristic magnetic resonance imaging findings observed during the first 4 years of life in patients with hypoxic-ischemic encephalopathy.
Section snippets
Patient data
Twenty-four neonates who suffered perinatal asphyxia and had hypoxic-ischemic encephalopathy were included in a prospective study. Term infants older than 37 weeks of gestation who manifested signs of fetal distress before delivery (including abnormal cardiotocograph recordings such as decreased variability, late decelerations, and a baseline bradycardia) with or without meconium-stained amnistic fluid,who had abnormal Apgar scores (≤6 at 5 minutes), who required resuscitation at birth and who
Results
All infants were 37 weeks of age or older by maternal dates or Dubowitz examination. The mean birth weight was 3184.2 ± 89.0 gm (range 2300-4000 gm), mean gestation was 39.5 ± 0.2 weeks (range 38-42 weeks). There were 17 male infants and 7 females. The perinatal characteristics and demographic features of allinfants are listed in Table 1.
Three patients died between 8-22 months; one died as a result of aspiration secondary to neurologic handicap, and the remaining two died as a direct result of
Discussion
In this study, normal magnetic resonance imaging findings in the neonatal period were associated with normal neurologic outcome, and magnetic resonance imaging findings both at 4 months and 4 years of age had the highest predictive value in predicting the abnormal neurologic outcome at 4 years of age. We think that the magnetic resonance imaging at 4 months of age is more important because it can be an early clue in predicting a poor neurologic outcome. It will be appropriate to monitor the
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