Anisotropic diffusion properties in infants with hydrocephalus: a diffusion tensor imaging study.

BACKGROUND AND PURPOSE Diffusion tensor imaging (DTI) can noninvasively detect in vivo white matter (WM) abnormalities on the basis of anisotropic diffusion properties. We analyzed DTI data retrospectively to quantify the abnormalities in different WM regions in children with hydrocephalus during early infancy. MATERIALS AND METHODS Seventeen infants diagnosed with hydrocephalus (age range, 0.13-16.14 months) were evaluated with DTI and compared with 17 closely age-matched healthy children (age range, 0.20-16.11 months). Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity values in 5 regions of interest (ROIs) in the corpus callosum and internal capsule were measured and compared. The correlation between FA and age was also studied and compared by ROI between the 2 study groups. RESULTS Infants with hydrocephalus had significantly lower FA, higher MD, and higher radial diffusivity values for all 3 ROIs in the corpus callosum, but not for the 2 ROIs in the internal capsule. In infants with hydrocephalus, the increase of FA with age during normal development was absent in the corpus callosum but was still preserved in the internal capsule. There was also a significant difference in the frequency of occurrence of abnormal FA values in the corpus callosum and internal capsule. CONCLUSIONS This retrospective DTI study demonstrated significant WM abnormalities in infants with hydrocephalus in both the corpus callosum and internal capsule. The results also showed evidence that the impact of hydrocephalus on WM was different in the corpus callosum and internal capsule.