OP14.07: Outcomes of fetuses with small cerebellum on second and third trimester ultrasonography

Abstract

Objectives: Recent neuropathology studies suggest changes at the gap junctions of ependymal cells as the common denominator for migrational abnormalities in fetal hydrocephalus. This fetal MRI study aims to assess the ganglionic eminence (GE) in cases of fetal myelomeningocele and aqueductal stenosis to identify migrational alterations of this specific brain compartment in the setting of fetal hydrocephalus. Methods: This retrospective observational single centre 1.5 Tesla MR study included myelomeningocele/Chiari II and/or aqueductal stenosis cases imaged between 18 and 24 gestational weeks (GW). Fetal MR consisted of T2-w and SSFP sequences in 3 orthogonal planes and echoplanar sequences. A pediatric neuroradiologist reviewed the cases and assessed the following features: -morphology of the GE, -width of the internal and external CSF spaces. The frequency of GE abnormalities was documented. In 5 cases postmortem MRI was available. Results: Identification and segmentation of the ''finger like'' extensions from the GE into the ventricular zone of the lateral ventricles in 4/5 postmortem cases. These changes were identified in 8/20 in vivo Chiari cases (Figure 1). They displayed isointense signals to gray matter and germinal matrix. The mean atrial width in the cases with GE abnormalities was 17,1mm, and in cases without GE changes 11.5mm. Conclusions: Changes of the fetal ependyma cause migrational abnormalities, which are usually only seen at the microscopic level. Here, we were able to demonstrate a specific MR sign of abnormal migration -the GE fingers -in cases of fetal hydrocephalus, imaged before 24GW.Supporting information can be found in the online version of this abstract Objectives: The hippocampus has been associated with numerous pathological situations from the agenesis of corpus callosum to Alzheimer disease and there has been a growing interest for its early study beginning with the study of Kier in 1997. Our objective was to recognise it by ultrasound in the fetal period. Methods: We assessed our ability in finding the image of the hippocampus in pre-existent 3D volumes from our Prenatal Diagnosis Unit. The volumes stored were from scans between 23 to 28 weeks gestational age. The technique used the one described by L. Gyndes and was used by all participants in the study for all of the 132 volumes. The study included both transabdominal and transvaginal acquired volumes. All volumes were analysed off-line using our computer software. Results:The technique has proved efficient for 87 % (50/57) transvaginal volumes and for 82% (62/75) trans abdominal volumes. The two main criteria for obtaining good results were the quality of the volumes and the experience of the sonographer in navigating 3D volumes. Conclusions:The fetal hippocampus can be obtained from CNS volumes in over 80% of cases and though it is not a part of routine investigation, it important to know it is accessible. OP14.07Outcomes of fetuses with small cerebellum on second and third trimester ultrasonography Objectives: We examined th...