Sonographic Imaging of the Glycogen Stage of the Fetal Choroid Plexus

At 8–22 weeks gestation, the lateral ventricular choroid plexus swells with glycogen deposits, which are thought to be an important source of anaerobic energy for a relatively hypovascular stage of brain development. Sonographic images during this phase demonstrate enlarged and echogenic ventricles, accounting for up to 80%–90% of the cerebral axial dimension in the earliest gestations studied. This increased echogenicity may be due to these glycogen stores. Because a rapid but sonographically definable decrease in the relative size of these structures occurs, routine imaging for the presence and character of the choroid plexus might prove to be a useful parameter in fetal examination.