Fetal choroid plexus vascularization assessed by color flow ultrasonography

We investigated the development of intracranial vascularization in the human fetus, with particular emphasis on the choroid plexus. The fetal brain was visualized in 102 patients with healthy pregnancies between 9 and 16 weeks' gestation. Imaging was done transvaginally except in the pregnancies of longer duration with unfavorable fetal positions. Color flow imaging was used to identify vessels in the cranium and within the choroid plexus. Pulsed Doppler signals were obtained from an internal carotid-middle cerebral artery and from a choroid plexus vessel. The pulsatility index was calculated from the Doppler spectral envelope. A major cerebral vessel could be seen at 9 weeks' gestation. Choroid plexus vessels were first seen at 10 weeks 3 days. Visualization rates ranged from 35 to 75% for plexus vessels, and 65 to 100% for cerebral vessels. Visualization of choroid plexus vessels was maximal at 13 weeks. The pulsatility index for the cerebral arteries at this gestational period averaged 2.6 +/- 0.6. The result for the choroid plexus was 1.66 +/- 0.5. (P < 0.001). Visualization of the vessels of the choroid plexus increases and decreases as the gland develops and shrinks. This developmental period also is the time of active neurogenesis.