Development of the Fetal Brain Structural Connectivity Based on In-Utero Diffusion MRI

Extensive cortico-cortical connections emerge in the fetal brain during the second-to-third trimester with the rapid development of white matter fiber pathways. However, the early establishment and prenatal development of the brain’s structural network are not yet understood. In this work, we used in-utero diffusion MRI data of fetuses from 26 to 38 gestational weeks to build the fetal brain structural connectivity networks (SCN). Graph theory was adopted to investigate the developmental patterns of the fetal brain SCN. Network analyses revealed increasing global and local efficiency, modularity, and small worldness of the fetal brain during development. We observed the strengthening of short-range cortico-cortical connections and the weakening of long-range connections, reflecting the distinct developmental events of short and long-range fiber pathways during the studied period. The fetal brain SCN underwent complicated changes during the late-second-to-third trimester. The findings of this study provided valuable information on the early developmental patterns of brain cortico-cortical structural connectivity.