OC10.07: Fetal advanced neurosonography in the first trimester of pregnancy

To evaluate the reproducibility and feasibility of incorporating an advanced central nervous system (CNS) assessment protocol, based on multiplanar evaluation and incorporation of predictive markers of CNS pathology into conventional first trimester ultrasound. This was a prospective observational study conducted from July to November 2023. Single gestations between 12+3 to 13+6 w(CRL 60-82mm) with a normal ultrasound scan were included. CNS was evaluated qualitatively and quantitatively in the axial plane: the insula(I), lateral ventricles(LV), choroid plexuses of the lateral ventricles(CPLV), tectum(Tec), aqueduct of Sylvius(AqS), distance from the aqueduct of Sylvius to the occipital bone(Aq-OB), cerebellum(C), fourth ventricle(4V), and cisterna magna(CM). In the sagittal view: brainstem(BS), fourth lines-three anechoic spaces(4L3S), fourth ventricle(4V), fourth ventricle choroid plexuses (4VCP), cisterna magna(CM) and brainstem to occipital bone(BSOB) distance were assessed. A total of 92 fetuses were included. The advanced scan was complete in 93.5% of the cases. In the axial planes: the lengths of the CPLV, LV and I were measured in 100% of cases, and in all sagittal structures. The 4V, 4VCP and the CM were measured in 97.8% of cases, the C in 96.7% and the Aq-OB distance in 95.7%. In the sagittal plane: BS, IT, CM and BSOB distance could be assessed and measured in 100% of cases. The best way to assess the structures was the vaginal route for the basic examination (52%) and axial planes (83%) and the abdominal route for sagittal planes(93%). A good intra- and interobserver agreement was obtained for all parameters evaluated. The median examination time was 13 minutes in the study group and 10 minutes in the control group (conventional screening). Performing an advanced evaluation of the CNS in the first trimester, combined with the integration of the described early markers for the prediction of CNS abnormalities, is possible with good intra- and interobserver agreement and without excessive increasing of the ultrasound examination time.