Volumetric Analysis of the Germinal Matrix and Lateral Ventricles Performed Using MR Images of Postmortem Fetuses

Images show good correlation between macroscopic brain (upper row) and 3D surface-rendered brain (middle row). Germinal matrix (orange), located ventrolateral to the lateral ventricles (blue), extends along the lateral walls of the lateral ventricles (lower row).

Successive images show developmental changes of lateral configuration of brain, germinal matrix, and ventricular system. The brain surfaces (upper row), germinal matrix (middle row, orange), and ventricular system (lower row, blue) of human fetal brain were reconstructed by surface rendering. The volume of the germinal matrix increased until 23 weeks' GA and decreased rapidly at 28 weeks' GA. Note how lateral ventricles change from fetal type, with vesicular aspect and bicornuate shape, to adult type with increasing GA.

Serial coronal MR images of the fetus at 7 weeks' GA. Germinal matrix cannot be detected

Serial coronal MR images of the fetus at 9 weeks' GA. Note germinal matrix is detected ventrolateral to the lateral ventricles (arrow)

Volumetric changes of the fetal brain (open triangles), germinal matrix (open circles), and lateral ventricles (solid circles). Increasing fetal brain volume (gray curve) has an exponential relationship (r² = .963) to GA, reaching 132.5 cm³ at 28 weeks' GA. The germinal matrix also increases exponentially, reaching a volume of 2.3 cm³ at 23 weeks' GA, then decreases rapidly after 25 weeks' GA. In contrast to the germinal matrix, the volume of the lateral ventricles gradually increases, up to 2.6 cm³ at 23 weeks' GA