Absent cavum septum pellucidum: a review with emphasis on associated commissural abnormalities

Abstract

The cavum septum pellucidum (CSP) is an important fetal midline forebrain landmark, and its absence often signifies additional underlying malformations. Frequently detected by prenatal sonography, absence of the CSP requires further imaging with pre- or postnatal MRI to characterize the accompanying abnormalities. This article reviews the developmental anatomy of the CSP and the pivotal role of commissurization in normal development. An understanding of the patterns of commissural abnormalities associated with absence of the CSP can lead to improved characterization of the underlying spectrum of pathology.

Relationship Between Cavum Septi Pellucidi Measurements and Fetal Hypoplastic Left Heart Syndrome or Dextro‐Transposition of the Great Arteries

“…The CSP is a midline space filled with cerebrospinal fluid interposed between the laminae of the septi pellucidi. The CSP is formed at 12 to 14 weeks' gestation from the median groove and extended posteriorly when the posterior extension of the corpus callosum occurs . On prenatal sonography, it can be visualized between the anterior horns of lateral ventricles.…”

Prenatally diagnosed developmental abnormalities of the central nervous system and genetic syndromes: A practical review

“…The CSP is visible as early as 15 weeks and should be seen between 18 and 37 weeks, after which it begins to narrow . Absent CSP is rare and usually an early sign of other midline forebrain anomalies, such as HPE and ACC, but it can be a normal variant with good prognosis .…”

“…The CSP is visible as early as 15 weeks and should be seen between 18 and 37 weeks, after which it begins to narrow . Absent CSP is rare and usually an early sign of other midline forebrain anomalies, such as HPE and ACC, but it can be a normal variant with good prognosis . If the CSP is not seen by 18 to 20 weeks' gestation, further evaluation, including MRI, is indicated to search for other brain abnormalities that may indicate the presence of a genetic syndrome.…”

“…Absent CSP is rare and usually an early sign of other midline forebrain anomalies, such as HPE and ACC, but it can be a normal variant with good prognosis . If the CSP is not seen by 18 to 20 weeks' gestation, further evaluation, including MRI, is indicated to search for other brain abnormalities that may indicate the presence of a genetic syndrome. When frontal horns are small, partial or complete ACC with or without other migrational abnormalities can be present.…”

Diagnostic accuracy and clinical outcomes associated with prenatal diagnosis of fetal absent cavum septi pellucidi

“…The visualization of the CSP in the mid second trimester is an important marker of the health and normal formation of midline, supratentorial structures (Figure ). Absence of the CSP has been appreciated on prenatal and postnatal imaging and is thought to result from the structural malformation of adjacent structures or a destructive or compressive process . As such, the absence or non‐visualization of the CSP on prenatal and postnatal imaging is historically associated with a range of anomalies including agenesis of the corpus callosum, holoprosencephaly, aqueductal stenosis, asymmetric ventriculomegaly with interhemispheric cyst and dysgenesis of corpus callosum (AVID), and schizencephaly; however, as prenatal diagnosis has evolved, cases of isolated absent CSP have also been identified .…”