Clinical Significance of MRI in Hypoxic-Ischemic Encephalopathy During Neonatal Period

ABSTRACT

PURPOSE: Hypoxic-ischemic encephalopathy is a major neurologic problem and one of the most important perinatal causes of neurological morbidity. Evaluation of the presence, extent, and subsequent evolution of hypoxic-ischemic lesions may be very important. We studied the significance of imaging modality through the analysis of brain MRI findings of hypoxic-ischemic encephalopathy during neonatal period and comparison with findings of brain ultrasonography. METHODS: We analysed the forty-seven infants retrospectively who were diagnosed as hypoxic-ischemic encephalopathy and underwent brain MRI and ultrasonography from Jan. 1992 to May 1996. RESULTS: 1) The mean gestational age and birth weight of the twenty-seven infants who were premature were 32.8+/-2.08weeks and 1.97+/-0.44kg respectively. The mean gestational age and birth weight of twenty infants who were fullterm were 39.3+/-1.04weeks and 2.98+/- 0.93kg respectively. The primary hypoxic-ischemic insults occurred during antenatal, intrapartum and postnatal period. 2) The findings of brain MRI were classified into periventricular leukomalacia, encephalomalacia, basal ganglia lesion, focal parenchymal hemorrhage, ventriculomegaly without other lesion and normal finding. 3) Three infants among twenty-five infants with periventricular leukomalacia, four infants among seven infants with basal ganglia lesion and six infants among seven infants with focal parenchymal hemorrhage were not diagnosed by brain ultrasonography. 4) All of ten infants with encephalomalacia and four infants with ventriculomegaly without other lesion were diagnosed by brain ultrasonography. CONCLUSIONS: MRI can diagnose the hypoxic-ischemic lesions which would not be possible by brain ultrasonography. Therefore MRI is the imaging modality of choice for diagnosis in infants with hypoxic-ischemic encephalopathy. We believe that the benefits of MRI outweigh its somewhat higher cost, lack of portability and monitoring difficulties.