@article {Cesaretti521, author = {C. Cesaretti and M. Nanni and T. Ghi and C. Parazzini and G. Conte and E. Contro and G. Grisolia and A. Righini}, title = {Variability of Forebrain Commissures in Callosal Agenesis: A Prenatal MR Imaging Study}, volume = {37}, number = {3}, pages = {521--527}, year = {2016}, doi = {10.3174/ajnr.A4570}, publisher = {American Journal of Neuroradiology}, abstract = {BACKGROUND AND PURPOSE: Agenesis of the corpus callosum, even when isolated, may be characterized by anatomic variability. The aim of this study was to describe the types of other forebrain commissures in a large cohort of randomly enrolled fetuses with apparently isolated agenesis of the corpus callosum at prenatal MR imaging.MATERIALS AND METHODS: All fetuses with apparent isolated agenesis of the corpus callosum undergoing prenatal MR imaging from 2004 to 2014, were evaluated for the presence of the anterior or a vestigial hippocampal commissure assessed in consensus by 2 pediatric neuroradiologists.RESULTS: Overall, 62 cases of agenesis of the corpus callosum were retrieved from our data base. In 3/62 fetuses (4.8\%), no forebrain commissure was visible at prenatal MR imaging, 23/62 fetuses (37.1\%) presented with only the anterior commissure, and 20/62 fetuses (32.3\%) showed both the anterior commissure and a residual vestigial hippocampal commissure, whereas in the remaining 16/62 fetuses (25.8\%), a hybrid structure merging a residual vestigial hippocampal commissure and a rudiment of the corpus callosum body was detectable. Postnatal MR imaging, when available, confirmed prenatal forebrain commissure findings.CONCLUSIONS: Most fetuses with apparent isolated agenesis of the corpus callosum showed at least 1 forebrain commissure at prenatal MR imaging, and approximately half of fetuses also had a second commissure: a vestigial hippocampal commissure or a hybrid made of a hippocampal commissure and a rudimentary corpus callosum body. Whether such variability is the result of different genotypes and whether it may have any impact on the long-term neurodevelopmental outcome remains to be assessed.ACanterior commissureACCagenesis of the corpus callosumCCcorpus callosumGAgestational ageHChippocampal commissureHShybrid structure}, issn = {0195-6108}, URL = {https://www.ajnr.org/content/37/3/521}, eprint = {https://www.ajnr.org/content/37/3/521.full.pdf}, journal = {American Journal of Neuroradiology} }