title: Variability of Forebrain Commissures in Callosal Agenesis: A Prenatal MR Imaging Study.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: From the Radiology and Neuroradiology Department (C.C., C.P., G.C., A.R.), Children's Hospital V. Buzzi, Milan, Italy Medical Genetics Unit (C.C.), Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy claudia.cesaretti@gmail.com.
authors.forename: C
authors.identifier: http://orcid.org/0000-0002-6819-0846
authors.initials: C
authors.lastname: Cesaretti
authors.affiliation: Fetal Medicine Unit (M.N., T.G., E.C.), S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy Obstetrics and Gynecology Department (M.N., G.G.), Carlo Poma Hospital, Mantova, Italy.
authors.forename: M
authors.identifier: http://orcid.org/0000-0002-7152-9150
authors.initials: M
authors.lastname: Nanni
authors.affiliation: Fetal Medicine Unit (M.N., T.G., E.C.), S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy Obstetrics Department (T.G.), Ospedale Maggiore, University of Parma, Parma, Italy.
authors.forename: T
authors.identifier: http://orcid.org/0000-0003-1823-1096
authors.initials: T
authors.lastname: Ghi
authors.affiliation: From the Radiology and Neuroradiology Department (C.C., C.P., G.C., A.R.), Children's Hospital V. Buzzi, Milan, Italy.
authors.forename: C
authors.identifier: http://orcid.org/0000-0003-0364-8673
authors.initials: C
authors.lastname: Parazzini
authors.affiliation: From the Radiology and Neuroradiology Department (C.C., C.P., G.C., A.R.), Children's Hospital V. Buzzi, Milan, Italy Department of Health Sciences (G.C.), University of Milan, Milan, Italy.
authors.forename: G
authors.identifier: http://orcid.org/0000-0002-1562-7389
authors.initials: G
authors.lastname: Conte
authors.affiliation: Fetal Medicine Unit (M.N., T.G., E.C.), S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
authors.forename: E
authors.identifier: http://orcid.org/0000-0001-9017-0940
authors.initials: E
authors.lastname: Contro
authors.affiliation: Obstetrics and Gynecology Department (M.N., G.G.), Carlo Poma Hospital, Mantova, Italy.
authors.forename: G
authors.identifier: http://orcid.org/0000-0001-5314-7231
authors.initials: G
authors.lastname: Grisolia
authors.affiliation: From the Radiology and Neuroradiology Department (C.C., C.P., G.C., A.R.), Children's Hospital V. Buzzi, Milan, Italy.
authors.forename: A
authors.identifier: http://orcid.org/0000-0003-3396-7413
authors.initials: A
authors.lastname: Righini
mesh_terms: D061085:Agenesis of Corpus Callosum / Q000473:pathology*; D003952:Diagnostic Imaging; D005333:Fetus; D020712:Fornix, Brain / Q000002:abnormalities*; D006801:Humans