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Non-visualisation of cavum septi pellucidi: implication in prenatal diagnosis?

Hosseinzadeh K, Luo J, Borhani A, Hill L - Insights Imaging (2013)

Bottom Line: This manuscript reviews congenital anomalies and imaging findings associated with non-visualisation of the cavum septi pellucidi (CSP) found on prenatal sonogram.Isolated septal deficiency, a rare but controversial entity, is considered a variant of normal.Common pitfalls in the sonographic evaluation of CSP include columns of the fornix that mimic CSP, and prominent cavum vergae that can simulate non-visualisation of the CSP.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Presbyterian South Tower, University of Pittsburgh Medical Center, 200 Lothrop Street, Suite 3950, Pittsburgh, PA, 15213, USA, hosseinzadehk@upmc.edu.

ABSTRACT

Objective: This manuscript reviews congenital anomalies and imaging findings associated with non-visualisation of the cavum septi pellucidi (CSP) found on prenatal sonogram.

Background: Observation of a normal cavum septi pellucidi (CSP) is an important landmark in the second and third trimester prenatal ultrasound evaluation of the fetal brain, and its visualisation provides reassurance of normal central forebrain development. Non-visualisation of the CSP is a prenatal sonographic finding, which in most cases is associated with neuroanatomical anomalies that include agenesis of the corpus callosum, schizencephaly, septo-optic dysplasia, holoprosencephaly, chronic hydrocephalus and acquired fetal brain injury. Isolated septal deficiency, a rare but controversial entity, is considered a variant of normal. Common pitfalls in the sonographic evaluation of CSP include columns of the fornix that mimic CSP, and prominent cavum vergae that can simulate non-visualisation of the CSP. When non-visualisation of the CSP is suspected, magnetic resonance imaging (MRI) of the fetal brain can confirm and evaluate associated anomalies.

Conclusion: Visualisation of the CSP is an integral component of the prenatal ultrasound and its non-visualisation is associated with other malformations, diagnosis of which is aided by MRI.

Teaching points: • Cavum septi pellucidi (CSP) is an important landmark in the prenatal ultrasound evaluation of the fetal brain, and is a marker for normal central forebrain development. • Non-visualisation of the CSP is most commonly associated with other neuroanatomical abnormalities. • Examination of the fetal brain by MRI can confirm the sonographic findings and evaluate for associated anomalies.

No MeSH data available.


Related in: MedlinePlus

Hydranencephaly. a Coronal ultrasound at 20 weeks’ gestation demonstrates non-visualisation of CSP, and significant CSF-filled supratentorial cavity (asterisk). Anterior falx is faintly present (arrow), which excludes alobar HPE. b Axial T2-weighted MRI at 22 weeks’ gestation demonstrates extensive destruction of hemispheres. There is sparing of the cerebellum (c), midbrain (mid), thalami (t) and occipital lobes (occ), which are regions supplied by the vertebrobasilar artery. Cortical rim is absent excluding severe hydrocephalus and confirming hydranencephaly
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Fig8: Hydranencephaly. a Coronal ultrasound at 20 weeks’ gestation demonstrates non-visualisation of CSP, and significant CSF-filled supratentorial cavity (asterisk). Anterior falx is faintly present (arrow), which excludes alobar HPE. b Axial T2-weighted MRI at 22 weeks’ gestation demonstrates extensive destruction of hemispheres. There is sparing of the cerebellum (c), midbrain (mid), thalami (t) and occipital lobes (occ), which are regions supplied by the vertebrobasilar artery. Cortical rim is absent excluding severe hydrocephalus and confirming hydranencephaly

Mentions: Hydranencephaly is the most severe form and is characterised by the complete or almost complete absence of cerebral cortex, which is replaced by fluid (Fig. 8). Hydranencephaly is a rare congenital anomaly occurring in less than 1 in 10,000 births. Non-visualisation of the CSP is an expected and obvious finding, overshadowed by the gross intracranial findings. It can be differentiated from HPE by identifying dural attachments and separate thalami on prenatal ultrasound [33]. While the aetiology is variable (infectious, toxic, iatrogenic, genetic, etc.), the likely pathogenic mechanism of hydranencephaly is early bilateral internal carotid occlusion with sparing of structures supplied by the vertebrobasilar system, including the brainstem, thalami, basal ganglia, cerebellum and portions of the temporal/occipital regions. On ultrasound, the characteristic necrotic brain tissue and blood may be visualised as a large, fluid-filled intracranial cavity with variable echogenicity [34]. If hydranencephaly occurs early in fetal development, the fetus may have microcephaly. Hydranencephaly can be confidently differentiated from severe chronic hydrocephalus by MRI, which can confirm the absence of cerebral cortex. Polyhydramnios may be present by the end of the second trimester because of poor fetal swallowing, but fetal movement is usually preserved. Prognosis is poor and neonates are neurologically devastated and rarely survive beyond infancy.Fig. 8


Non-visualisation of cavum septi pellucidi: implication in prenatal diagnosis?

Hosseinzadeh K, Luo J, Borhani A, Hill L - Insights Imaging (2013)

Hydranencephaly. a Coronal ultrasound at 20 weeks’ gestation demonstrates non-visualisation of CSP, and significant CSF-filled supratentorial cavity (asterisk). Anterior falx is faintly present (arrow), which excludes alobar HPE. b Axial T2-weighted MRI at 22 weeks’ gestation demonstrates extensive destruction of hemispheres. There is sparing of the cerebellum (c), midbrain (mid), thalami (t) and occipital lobes (occ), which are regions supplied by the vertebrobasilar artery. Cortical rim is absent excluding severe hydrocephalus and confirming hydranencephaly
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig8: Hydranencephaly. a Coronal ultrasound at 20 weeks’ gestation demonstrates non-visualisation of CSP, and significant CSF-filled supratentorial cavity (asterisk). Anterior falx is faintly present (arrow), which excludes alobar HPE. b Axial T2-weighted MRI at 22 weeks’ gestation demonstrates extensive destruction of hemispheres. There is sparing of the cerebellum (c), midbrain (mid), thalami (t) and occipital lobes (occ), which are regions supplied by the vertebrobasilar artery. Cortical rim is absent excluding severe hydrocephalus and confirming hydranencephaly
Mentions: Hydranencephaly is the most severe form and is characterised by the complete or almost complete absence of cerebral cortex, which is replaced by fluid (Fig. 8). Hydranencephaly is a rare congenital anomaly occurring in less than 1 in 10,000 births. Non-visualisation of the CSP is an expected and obvious finding, overshadowed by the gross intracranial findings. It can be differentiated from HPE by identifying dural attachments and separate thalami on prenatal ultrasound [33]. While the aetiology is variable (infectious, toxic, iatrogenic, genetic, etc.), the likely pathogenic mechanism of hydranencephaly is early bilateral internal carotid occlusion with sparing of structures supplied by the vertebrobasilar system, including the brainstem, thalami, basal ganglia, cerebellum and portions of the temporal/occipital regions. On ultrasound, the characteristic necrotic brain tissue and blood may be visualised as a large, fluid-filled intracranial cavity with variable echogenicity [34]. If hydranencephaly occurs early in fetal development, the fetus may have microcephaly. Hydranencephaly can be confidently differentiated from severe chronic hydrocephalus by MRI, which can confirm the absence of cerebral cortex. Polyhydramnios may be present by the end of the second trimester because of poor fetal swallowing, but fetal movement is usually preserved. Prognosis is poor and neonates are neurologically devastated and rarely survive beyond infancy.Fig. 8

Bottom Line: This manuscript reviews congenital anomalies and imaging findings associated with non-visualisation of the cavum septi pellucidi (CSP) found on prenatal sonogram.Isolated septal deficiency, a rare but controversial entity, is considered a variant of normal.Common pitfalls in the sonographic evaluation of CSP include columns of the fornix that mimic CSP, and prominent cavum vergae that can simulate non-visualisation of the CSP.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Presbyterian South Tower, University of Pittsburgh Medical Center, 200 Lothrop Street, Suite 3950, Pittsburgh, PA, 15213, USA, hosseinzadehk@upmc.edu.

ABSTRACT

Objective: This manuscript reviews congenital anomalies and imaging findings associated with non-visualisation of the cavum septi pellucidi (CSP) found on prenatal sonogram.

Background: Observation of a normal cavum septi pellucidi (CSP) is an important landmark in the second and third trimester prenatal ultrasound evaluation of the fetal brain, and its visualisation provides reassurance of normal central forebrain development. Non-visualisation of the CSP is a prenatal sonographic finding, which in most cases is associated with neuroanatomical anomalies that include agenesis of the corpus callosum, schizencephaly, septo-optic dysplasia, holoprosencephaly, chronic hydrocephalus and acquired fetal brain injury. Isolated septal deficiency, a rare but controversial entity, is considered a variant of normal. Common pitfalls in the sonographic evaluation of CSP include columns of the fornix that mimic CSP, and prominent cavum vergae that can simulate non-visualisation of the CSP. When non-visualisation of the CSP is suspected, magnetic resonance imaging (MRI) of the fetal brain can confirm and evaluate associated anomalies.

Conclusion: Visualisation of the CSP is an integral component of the prenatal ultrasound and its non-visualisation is associated with other malformations, diagnosis of which is aided by MRI.

Teaching points: • Cavum septi pellucidi (CSP) is an important landmark in the prenatal ultrasound evaluation of the fetal brain, and is a marker for normal central forebrain development. • Non-visualisation of the CSP is most commonly associated with other neuroanatomical abnormalities. • Examination of the fetal brain by MRI can confirm the sonographic findings and evaluate for associated anomalies.

No MeSH data available.


Related in: MedlinePlus