PT  - JOURNAL ARTICLE
AU  - C. Cesaretti
AU  - M. Nanni
AU  - T. Ghi
AU  - C. Parazzini
AU  - G. Conte
AU  - E. Contro
AU  - G. Grisolia
AU  - A. Righini
TI  - Variability of Forebrain Commissures in Callosal Agenesis: A Prenatal MR Imaging Study
AID  - 10.3174/ajnr.A4570
DP  - 2015 Oct 29
TA  - American Journal of Neuroradiology
4099  - http://www.ajnr.org/content/early/2015/10/29/ajnr.A4570.short
4100  - http://www.ajnr.org/content/early/2015/10/29/ajnr.A4570.full
AB  - 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.AbbreviationsACanterior commissureACCagenesis of the corpus callosumCCcorpus callosumGAgestational ageHChippocampal commissureHShybrid structure