title: Asymmetric ventriculomegaly, interhemispheric cyst, and dysgenesis of the corpus callosum (AVID): an imaging triad.
abstract: A series of 20 cases from 2 academic institutions is presented with a characteristic imaging triad of asymmetric ventriculomegaly, a large interhemispheric cyst, and partial or complete agenesis of the corpus callosum. Most cases were initially referred as aqueduct stenosis and hydrocephalus or focal porencephaly. We describe the imaging findings that identify an abnormal or absent corpus callosum associated with a type 1 interhemispheric cyst in fetuses initially thought to have hydrocephalus attributable to aqueductal stenosis. We suggest that the acronym AVID (asymmetric ventriculomegaly, interhemispheric cyst, and dysgenesis of the corpus callosum) may be useful in recognition of these cases. All cases presented with markedly asymmetric ventriculomegaly on initial sonography, with progressive hydrocephalus throughout gestation. Fetal magnetic resonance imaging was performed in 15 of 20 cases. Thirteen of 20 cases were identified in male fetuses. Associated fetal and postnatal abnormalities are also reported. Technological improvements in sonography and fetal magnetic resonance imaging allow improved characterization of associated intracranial anomalies in the setting of hydrocephalus. Accurate diagnosis can aid parental counseling, especially because isolated aqueductal stenosis suggests a better prognosis than hydrocephalus with anomalies. Markedly asymmetric ventriculomegaly in this series was the key to excluding isolated aqueductal stenosis and was associated with callosal malformation with a type 1a interhemispheric cyst.
authors.affiliation: Department of Radiology, Oregon Health and Science University, Mail Code L340, 3181 SW Sam Jackson Park Rd, Portland, OR 97239-3098, USA. ohk@ohsu.edu
authors.forename: Karen Y
authors.initials: KY
authors.lastname: Oh
authors.forename: Anne M
authors.initials: AM
authors.lastname: Kennedy
authors.forename: Nathan R
authors.initials: NR
authors.lastname: Selden
authors.forename: Logan
authors.initials: L
authors.lastname: McLean
authors.forename: Roya
authors.initials: R
authors.lastname: Sohaey
mesh_terms: D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging*; D061085:Agenesis of Corpus Callosum / Q000000981:diagnostic imaging*; D001927:Brain Diseases / Q000000981:diagnostic imaging*; D003560:Cysts / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000000981:diagnostic imaging*; D008297:Male; D016216:Ultrasonography, Prenatal / Q000379:methods*