Ultrasound visualization of the central nervous system during embryonic and fetal periods: Neurosonoembryology utilizing multiple three‐dimensional transvaginal ultrasound technology

Abstract

Objective: To study the ultrasonographic features of the central nervous system (CNS) in normally developing embryos and fetuses with a crown-rump length (CRL) of 10-84 mm, utilizing a high-frequency transvaginal probe in conjunction with various three-dimensional (3D) imaging modes.Methods: From January 2020 to February 2021, 210 normally developing embryos and fetuses in early pregnancy were enrolled and classified based on their gestational age. A high-frequency transvaginal transducer was used to perform 2D and 3D ultrasounds, and the 3D images were saved. These images were then processed using multiple 3D technologies, such as HD live silhouette, OmniView, and TUI. Additionally, the circumference of the vermis was measured through the posterior fontanelle.Results: Beginning at the 10 mm CRL stage of embryonic development, highfrequency transvaginal 3D ultrasound imaging was able to clearly visualize the prosencephalon, mesencephalon, and rhombencephalon. Notable changes were observed in the rhombencephalon during the 16-22 mm CRL stage, including the visualization of the pontine flexure and cerebellar primordium. At 23-40 mm CRL, there was a distinct pontine flexure, and the developing cerebellum, the fourth ventricle, and choroid plexus of the fourth ventricle (4th VCP) could be observed.The roof of the rhombencephalon was partitioned by the 4th VCP into the anterior membranous area (AMA) located rostrally and the posterior membranous area situated caudally. Additionally, the original Blake's pouch was identifiable. Among fetuses measuring 41-84 mm CRL, the AMA progressively decreased in size as the vermis developed. From the mid-sagittal view, the orientation of the 4th VCP seemed to shift from being perpendicular to the neural tube's long axis to being parallel to it. Furthermore, there was a significant correlation between CRL and vermis circumference. Conclusion:Using three-dimensional transvaginal ultrasound scanning, detailed visualization of the morphological changes in the CNS during normal embryonic Zexuan Yang and Fengqin Liu contribute equally to this work as co-first author.

The first trimester: The new focal point for prenatal screening and diagnosis

“…Despite showing a good performance of such a scan in their center, Pruthi and colleagues in Canada do not recommend implementing detailed first trimester anatomy scanning outside tertiary referral centers. 10 Research continues to bring new insights on the diagnostic ability of the early ultrasound scan: the fetal heart, 11 the central nervous system 12,13 skeletal dysplasias 14 and increased nuchal translucency. 15 Also, among the first trimester screening strategies for congenital anomalies discussed by Bardi et al, early anatomical assessment occupies a central role, from the most advanced to more traditional screening menus.…”