ABNORMALITIES OF THE CAVUM SEPTUM PELLUCIDUM (1-9)

o       NORMAL

o       ENLARGED

o       ABSENT

 

NORMAL CAVUM SEPTUM PELLUCIDUM

 

Link to normal cavum septum pellucidum 3-82

 

ENLARGED CAVUM SEPTUM PELLUCIDUM

Enlarged Cavum Septum Pellucidum  (>5 mm).

      • Bronshtein and Weiner (7) suggest a possible correlation with chromosomal aberrations and other malformations.
      • Vergani and associates (8), in a later study found all fetuses with a large cavum to be normal.

 

 

ABSENT CAVUM SEPTUM PELLUCIDUM

 

Absent Cavum Septum Pellucidum (3-6).

      • May be normal after 38 weeks GA.
      • Agenesis of the corpus callosum.
      • Holoprosencephaly.
      • Septo-optic dysplasia.
      • Schizencephaly.
      • Encephaloceles.
      • Heterotopic gray matter.destructive hydrocephalus
      • Porencephaly
      • Hydranencephaly
Primary

Abnormal ventral induction

Complete holoprosencephaly

Partial holoprosencephaly – midline interhemispheric variant

Secondary

Disruptive process

Either disruption of falx and cerebrum or enlargement of foramen of Monro

Valproic acid

Valproic acid embryopathy

 

 

 

Adapted from reference 9


 

 

 

Video clip of Absent Cavum Septum Pellucidum

 

 

 

Ultrasound

1.     Assess the location and extent of ventricular communication.

2.     Cleavage / non cleavage of hemispheres and deep fray nuclei

3.     Callosal abnormalities

4.     Other CNS, facial or body abnormalities

 

Alobar holoprosencephaly

Semilobar holoprosencephaly

o       Absent corpus callosum

o       Non cleavage of the cortex and basal ganglia                   (thalami – TH)

o       Callosal agenesis

o       No choroids plexus

o       Communication between ventricles is always             anteroposterior

o       Facial anomalies

·         Mild facial anomalies (midline cleft lip and palate).

·         Hypotelorism.

·         Single ventricular chamber with partially formed                                                                                               occipital horns and rudimentary temporal horns.

·         Peripheral rim of brain tissue several centimeters thick.

·         Partially fused thalami (situated anteriorly and                                                                                                                  abnormally rotated).

·         Small 3rd ventricle.

·         Absent cavum septum pellucidum, corpus callosum and                                                                                         olfactory bulb.

·         Rudimentary falx cerebri and interhemispheric fissure.

 

Schizencephaly

Septo-optic dysplasia

  • Absent cavum septum pellucidum

o       Cortical disturbance – peripheral clefts communicating              

            with the ventricles.

o       Absent cavum septum pellucidum

  • Mild ventriculomegaly
  • Normal corpus callosum
  • Optic nerve hypoplasia

Hydrocephalus

  • Anterior portions of ventricle separated by falx
  • Communication between ventricles is only in the                            medial portion
  • Normal cleavage of hemispheres
  • Separated thalami
  • Normal corpus callosum
  • Both choroid plexus on same side.
  • Normal face

 

 

 

REFERENCES
  1. DeMyer W. Classification of cerebral malformations. Birth Defects Orig Artic Ser 1971;7:78.
  2. Fitz CR. Midline anomalies of the brain and spine. Radiol Clin North Am 1982;20:95.
  3. Falco P, Gabrielli A, Visentin A et.al. Transabdominal sonography of the cavum septum pellucidum in normal fetuses in the second and third trimester of pregnancy. Ultrasound Obstet Gynecol 2000;16:549-553.
  4. Jou HJ, Shyu MK, Chen SM et.al. Ultrasound measurements of the fetal cavum septi pellucidi. Ultrasound Obstet Gynecol 1998;12:419-421.
  5. Pilu G, Sandri F, Cerisoli M et.al. Sonographic findings in septo-optic dysplasia in the fetus and newborn infant. Am J Perinatal 1990;7:337-340.
  6. Pilu G, Falco P, Perola A et.al. Differential diagnosis and outcome of fetal intracranial hypoechoic lesions report of 21 cases. Ultrasound Obstet Gynecol 1997;9:229-234.
  7. Bronshtein M, Weiner Z. Prenatal diagnosis of dilated cava septi pellucidi and vergae: associated anomalies, differential diagnosis, and pregnancy outcome. Obstet Gynecol 1992;80:838-842.
  8. Vergani P, Locatelli A, Piccoli MG et.al. Ultrasonographic differential diagnosis of fetal interhemispheric cysts. Am J Obstet Gynecol 1999;180:423-428.
  9. Malinger G, Lev D, Kidron D et.al. Differential diagnosis in fetuses with absent septum pellucidum. Ultrasound Obstet Gynecol 2005;25:42-49.