Abstract
OBJECTIVE: The objective of the study was to characterize total and regional volumetric brain growth in healthy fetuses during the second and third trimesters of pregnancy, using an automated method. STUDY DESIGN: We developed and validated an automated method to quantify global and regional in vivo brain volumes using fetal magnetic resonance imaging. We then computed the percentage of growth for each brain structure in a cohort of 64 healthy fetuses (25.4-36.6 weeks' gestational age). RESULTS: The cerebellum demonstrated the greatest maturation rate, with a 4-fold increase (384%) in volume between 25.4 and 36.6 weeks, and a relative growth rate of 12.87% per week. Both total brain and cerebral volumes increased by 230% and brain stem volume by 134% over the same gestational age period. Conversely, lateral ventricular volume decreased by 4.18% per week. CONCLUSION: The availability and ongoing validation of normative fetal brain growth trajectories will provide important tools for early detection of impaired fetal brain growth upon which to manage high-risk pregnancies.