European journal of radiology
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In this review, we demonstrate the developmental appearance, structural features, and reorganization of transient cerebral zones and structures in the human fetal brain using a correlative histological and MRI analysis. The analysis of postmortem aldehyde-fixed specimens (age range: 10 postovulatory weeks to term) revealed that, at 10 postovulatory weeks, the cerebral wall already has a trilaminar appearance and consists of: (1) a ventricular zone of high cell-packing density; (2) an intermediate zone; (3) the cortical plate (in a stage of primary consolidation) with high MRI signal intensity. The anlage of the hippocampus is present as a prominent bulging in the thin limbic telencephalon. ⋯ The period between 27 and 30 postovulatory weeks is characterized by gradual blurring of the laminar structure in parallel with the formation of cerebral convolutions. In near-term preterm infants, T2-weighted MR images showed better contrast resolution than T1-weighted images. We conclude that transient fetal zones and subcortical structures display characteristic MRI features due to the high content of extracellular matrix in the subplate zone, higher MRI signal intensity of zones with high cell-packing intensity, and the presence of growing fibers.