Neuroimaging abnormalities in infants with congenital hemiparesis.

Clinical and neuroimaging characteristics of congenital hemiparesis were examined in a retrospective cohort study nested within 199,176 births within the Kaiser Permanente Medical Care Program, 1997-2002. Infants with a physician diagnosis of paresis or cerebral palsy were electronically identified, and charts were reviewed to confirm congenital hemiparesis. A neuroradiologist reviewed available head MRI and CT scans. Of 96 infants with congenital hemiparesis (population prevalence 4.8 per 10,000), 81% received either a head magnetic resonance imaging (n = 55) or head computed tomography only (n = 23). Perinatal arterial infarction was the most common (30%) neuroimaging finding in term infants. Infants with right-sided hemiparesis (relative risk 4.6, 95% confidence interval 1.4-14.4) or moderate to severe weakness (relative risk 4.4, 95% confidence interval 1.1-17.7) were more likely to have had a perinatal arterial infarction. Periventricular white matter lesions predominated in preterm infants (71%). Brain malformations observed in 14 (18%) patients included polymicrogyria, heterotopia, and schizencephaly. The 14 infants (18%) with a normal head imaging study were more likely to outgrow all signs of hemiparesis by age 3 than were infants with an abnormal brain image (29% vs 0%, P < 0.001). Neuroimaging studies provide useful diagnostic and prognostic information in infants with congenital hemiparesis.