Spatiotemporal Patterning of Cortical Microstructure During Gestation

Motivation: Advances in MRI protocols for the fetal brain allow us to study neurodevelopmental mechanisms at both macroscopic and microscopic scales. Examining tissue microarchitecture in utero reveals how neuronal organization develops. Goal(s): Our goal is to map region-specific changes in cortical microstructure during intrauterine growth. Approach: We analyzed diffusion MRI data from fetuses scanned between 21 and 38 gestational weeks to chart growth trajectories of fractional anisotropy (FA) and mean diffusivity (MD) across 36 bilateral cortical regions. Results: Cortical FA and MD show diverse developmental patterns across regions, with both measures decreasing from the late second trimester through the end of the third trimester. Impact: In-utero characterization of cortical microstructure offers key insights into the development of brain connections and functions, aiding early detection of abnormalities linked to malformation and dysfunction.