Abstract
OBJECTIVE: The aim of the present study was to describe abnormal anatomical features of the anterior (AC) and posterior (PC) complexes identified during basic ultrasound assessment of the fetal brain in cases diagnosed with partial agenesis of the corpus callosum (pACC). METHODS: This was a retrospective observational study of 22 fetuses diagnosed with pACC between January 2010 and June 2024. The cases were reviewed by fetal neurosonographers who evaluated the morphology of AC and PC structures visualized during basic axial fetal brain screening at 20-33 weeks' gestation in three different referral centers in Chile and Spain. All cases were also assessed independently by another fetal neurosonographer who was blinded to the original reports, using images, videoclips and three-dimensional volume datasets. RESULTS: Regarding the structures that comprise the AC, the cavum septi pellucidi had an abnormal appearance in 20/22 cases and the anterior horn of the lateral ventricle had a dysmorphic pattern, characterized by being parallel to the midline, in 11/22 cases. PC abnormalities observed included widening of the interhemispheric fissure posteriorly in 20/22 cases, and absent callosal sulcus with no visualization of the corpus callosum crossing the midline in 19/22 cases. Observation of these PC abnormalities had a very high level of agreement between the original and the independent neurosonographers, ranging between 95% and 100%. CONCLUSION: Evaluation of the AC and PC during the basic examination of the fetal brain could significantly improve the prenatal diagnosis of corpus callosum dysgenesis. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.