ABNORMAL MAGNETIC-RESONANCE SIGNAL IN THE INTERNAL CAPSULE PREDICTS POOR NEURODEVELOPMENTAL OUTCOME IN INFANTS WITH HYPOXIC-ISCHEMIC ENCEPHALOPATHY

Objective. The aim of this study was to establish whether abnormal sig nal intensity in the posterior limb of the internal capsule (PLIC) on magnetic resonance imaging is an accurate predictor of neurodevelopmen tal outcome at 1 year of age in infants with hypoxic-ischemic encephal opathy (HIE). Methods. We have examined 73 term neonates with HIE betw een 1 and 17 days after birth with cranial magnetic resonance imaging and related the magnetic resonance imaging findings to neurodevelopmen tal outcome at 1 year of age. Results. All infants with an abnormal si gnal intensity in the PLIC developed neurodevelopmental impairment alt hough in 4 infants with very early scans the abnormal signal was not a pparent until up to 4 days after birth. A normal signal intensity was associated with a normal outcome in all but 4 cases; 3 of these infant s had minor impairments and all had persistent imaging changes within the white matter. The 4th infant with a normal signal intensity on day 2 died before a further image could be obtained. The absence of norma l signal predicted abnormal outcome in term infants with HIE with a se nsitivity of 0.90, a specificity of 1.0, a positive predictive value o f 1.0, and a negative predictive value of 0.87. The test correctly pre dicted outcome in 93% of infants with grade II HIE, according to the S arnat system. Ap plying a Bayesian approach, the predictive probabilit y of the test (the probability that the test would predict an outcome correctly) was distributed with a mean of 0.94 and 95% confidence limi ts of 0.89 to 1.0. Conclusion. Abnormal signal intensity in the PLIC i s an accurate predictor of neurodevelopmental outcome in term infants suffering HIE.