Post-hemorrhagic ventricular dilatation affects white matter maturation in extremely preterm infants

Background Data on microstructural white matter integrity in preterm infants with post-hemorrhagic ventricular dilatation (PHVD) using diffusion tensor imaging (DTI) are limited. Also, to date, no study has focused on the DTI changes in extremely preterm (EP) infants with PHVD. Methods A case–control study of EP infants <28 weeks’ gestation with PHVD was conducted. Diffusivity and fractional anisotropy (FA) values of corticospinal tracts (CST) and corpus callosum (CC) were measured using DTI at term-equivalent age. Outcomes were assessed at 2-years-corrected age. Results Twenty-one infants with PHVD and 21 matched-controls were assessed. FA values in the CC were lower in infants with PHVD compared with controls (mean difference, 0.05 [95% confidence interval (CI), 0.02–0.08], p < 0.001). In infants with periventricular hemorrhagic infarction, FA values in the CC were lower than in controls (mean difference, 0.05 [95% CI, 0.02–0.09], p = 0.005). The composite cognitive and motor scores were associated with the FA value of the CC (coefficient 114, p = 0.01 and coefficient 147, p = 0.004; respectively). Conclusions Extremely preterm infants with PHVD showed lower FA values in CC. A positive correlation was also shown between the composite cognitive and motor scores and FA value of the CC at 2-years-corrected age. Impact Extremely preterm infants with post-hemorrhagic ventricular dilatation showed lower fractional anisotropy values in their corpus callosum compared with controls reflecting the impaired microstructure of these commissural nerve fibers that are adjacent to the dilated ventricles. Impaired microstructure of the corpus callosum was shown to be associated with cognitive and motor scores at 2-years-corrected age.