Fetal MRI Reveals Altered Subplate Development in Congenital Heart Disease

The subplate, a transient fetal brain region crucial for early cerebral development, appears to be impacted by congenital heart disease (CHD). A retrospective observational study examined fetal MRI data from 76 CHD fetuses and 62 typically developing (TD) fetuses, all scanned between 21-32 weeks of gestation. The findings revealed that CHD fetuses had lower whole-brain subplate volume, corresponding to a 5.7% reduction compared to expected values. However, this difference diminished when accounting for global brain volume.

Regional analyses uncovered spatially structured deviations in subplate development, particularly in the posterior parietal, occipital, and temporal regions, with a left-hemisphere bias in subplate thickness. Normative modeling indicated bidirectional regional deviations and heightened inter-individual variability in CHD fetuses, with extreme subplate volume deviations observed in 73% of cortical regions.

Higher cerebroplacental ratio (CPR) was linked to thinner subplate thickness deviations, with this association becoming more pronounced after accounting for cerebral substrate delivery.

Among CHD fetuses who had postnatal follow-up, prenatal subplate deviations showed mild associations with neurodevelopmental outcomes. Specifically, right precuneus subplate thickness was associated with receptive and expressive communication scores on the Bayley Scales of Infant and Toddler Development. These results suggest that fetal subplate alterations in CHD are primarily characterized by overall reductions in brain growth, but also encompass spatially heterogeneous and individually variable regional deviations beyond global scaling.

The exploratory associations with fetal hemodynamics and postnatal neurodevelopment offer hypotheses for future research exploring the developmental implications of these prenatal alterations.