Diffusion Tensor Imaging of White Matter in Children Born from Preeclamptic Gestations

Abstract

Background and purpose: Individuals born from pregnancies complicated by preeclampsia have an elevated risk for cognitive impairment. Deviations in maternal plasma angiokines occur for prolonged intervals before clinical signs of preeclampsia. We hypothesized that fetal brain vascular and nervous tissue development become deviated during maternal progression toward preeclampsia and that such deviations would be detectable by MR imaging.

Materials and methods: In this pilot study, 10 matched (gestational and current ages) pairs (5 boys/5 girls, 7-10 years of age) from preeclampsia or control pregnancies were examined by using diffusion tensor MR imaging. An unbiased voxel-based analysis was conducted on fractional anisotropy and mean diffusivity parametric maps. Six brain ROIs were identified for subsequent analysis by tractography (middle occipital gyrus, caudate nucleus and precuneus, cerebellum, superior longitudinal fasciculus, and cingulate gyrus).

Results: Statistical differences were present between groups for fractional anisotropy in the caudate nucleus (offspring from preeclamptic gestation > controls), volume of the tract for the superior longitudinal fasciculus (offspring from preeclamptic gestation > controls) and the caudate nucleus (offspring from preeclamptic gestation > controls), and for parallel diffusivity of the cingulate gyrus (offspring from preeclamptic gestation > controls).

Conclusions: These novel preliminary results along with previous results from the same children that identified altered cerebral vessel calibers and increased regional brain volumes justify fully powered MR imaging studies to address the impact of preeclampsia on human fetal brain development.

Fig 1.

Voxel-based analysis comparing the brains of children born from preeclamptic pregnancies with the brains of children born from typical healthy pregnancies (controls). A custom template was created on the basis of the anatomic images of all 20 children enrolled in this study. Voxel-based analysis was performed to compare white matter measurements in PE-F1s and control children. The blue and red dots represent areas where there might have been differences between the fractional anisotropy values (A and C) or mean diffusivity values (B and D). From the voxel-based analysis, areas in which a cluster of voxels persisted through at least ≥3 sections were identified and used to define the specific ROIs to be used as seeds for tractography. Magnification of an area (C and D) is used as an example of how ROIs were defined. The 3 most dot-clustered regions in voxel-based analysis for FA and MD were selected, yielding 6 ROIs for more detailed analysis. The ROIs identified on FA were the following: 2, middle occipital gyrus; 7, caudate nucleus; and 9, precuneus. The ROIs identified on MD were the following: 1, cerebellum; 6, superior longitudinal fasciculus; and 7, cingulate gyrus.