Normal anatomy of the developing fetal brain. Ex vivo anatomical-magnetic resonance imaging correlation.

Fetal brain Magnetic Resonance Imaging (MRI) is a new technique of growing interest, with a high potential to detect prenatal central nervous system abnormalities. This requires an accurate knowledge of the normal morphological sequence of brain development. In this paper we studied the cortical development of post-mortem normal fetal brains, correlating MRI estimations of fetal age with in vitro anatomical and anthropometric measurements. Ten post-mortem fetal heads were submitted to MRI. Maturational state of sulci and gyri and gray-white matter differentiation were analysed in the MRIs and by dissection of the brains. The findings were correlated with the previously estimated ages of the fetuses, which varied between 17 and 38 weeks. Consistency between methods was assessed employing intraclass correlation coefficient and Bland-Altman plots, with a 95% confidence interval. Estimations of fetal age obtained by MRI were very similar to those achieved by anthropometric measurements or by considering anatomical parameters. Gyral development proved to be more precise than gray-white matter differentiation for this purpose. Fetal MRI proved to be as reliable as the macroscopic anatomical examination for depicting normal cortical developmental sequence and age, suggesting that this technique may be a suitable option for achieving precise information about the morphology of human brains along the gestational period.