Ganglionic eminence within the early developing brain visualized by 3D transvaginal ultrasound

Early diagnosis of cerebral congenital anomalies requires a profound knowledge of the anatomy of the developing human brain. The ganglionic eminences (GE) are crucial structures of the brain, giving rise mostly to the basal nuclei. The aim of this explorative study is to assess the GE within the embryonic and early fetal brain by using 3D transvaginal US.

From March 2015 to May 2015, a total of 18 singleton non-malformed embryos and fetuses at 9-13 weeks of gestation were assesed in vivo by transvaginal ultrasound using a Voluson E10, BT 15 scanner (GE Healthcare, Zipf, Austria). The 3D sonography was performed routinely as the subjects were scanned. Inter-observer agreement (concordance) was calculated using the Cohen's kappa statistics.

At 9 gestational weeks, no GE was identified. At 10 gestational weeks the GE were identified as mere thickenings in the lateral wall of the cerebral hemispheres, well depicted by 3D transvaginal ultrasound using the HDlive rendering mode and the OmniView® software. Starting with 11 gestational weeks the GE are evident. The results of inter-observer agreement for ganglionic eminences identification were as follows: observed agreement Po=0.94, expected agreement Pe=0.76, kappa coefficient=0.83, which means a very good agreement between the observers.

The GE can be clearly visualized by 3D transvaginal sonography, and especially by HDlive rendering mode. This method has become the "golden standard" for in vivo morphological studies of the embryonic and early fetal brain.