5 Cavum Septum Pellucidum



10.1055/b-0040-176841

5 Cavum Septum Pellucidum

Susana Calle, Pejman Rabiei, Shekhar D. Khanpara, and Roy F. Riascos

5.1 Case Presentation



5.1.1 History and Physical Examination


An 18-year-old man with no significant past medical history presents with an episode of seizure-like activity.


On physical examination, the patient is alert and oriented with no focal neurologic deficit.



5.1.2 Imaging Findings and Impression


Coronal CT scan of the head without contrast (▶ Fig. 5.1a) and brain MR images without contrast including axial T2-weighted (▶ Fig. 5.1b), axial T1-weighted (▶ Fig. 5.1c), and coronal fluid-attenuated inversion recovery (FLAIR; ▶ Fig. 5.1d) images show persistence of a fluid-filled cavity (white arrows) in between leaflets of the septum pellucidum extending posteriorly to the foramina of Monro, consistent with a cavum septum pellucidum. There is an incidental curvilinear pericallosal lipoma (white arrowhead) along the splenium.

Fig. 5.1 (a–d)


5.2 Differential Diagnosis




  • Cavum septum pellucidum (CSP):




    • It is a fluid-filled cavity within the leaflets of septum pellucidum, which follows the cerebrospinal fluid (CSF) signal intensity on all sequences located anterior to columns of fornix.



  • Cavum septum vergae (CSV):




    • Posterior extension of CSP beyond the columns of the fornix and foramen of Monro.



    • CSV is located posterior to the CSP and posterior and superior to the columns of fornix. 1



    • It is hypodense with CSF density on head CT scans without contrast. It follows CSF signal intensity on MR images of the brain and will be suppressed on FLAIR sequences.



    • Although the CSP and CSV are believed to represent anatomic variations, investigators have shown an increased prevalence of them in traumatic brain injury patients. 2 , 3



    • A large CSP in patients with schizophrenia can also be associated with more severe symptoms. 4



  • Cavum velum interpositum:




    • It is an enlarged potential space in between infolded layers of the velum interpositum.



    • Anatomically, it is triangle shaped and lies between the internal cerebral veins.



    • It is located below the column of the fornix and the splenium of corpus callosum and posterior to the foramen of Monro.



    • It has CSF-like density on head CT scans with a triangular configuration pointing forward and not extending anterior to the foramen of Monro. 5



    • Isointense to CSF on all MR sequences with a hypointense membrane surrounding it.

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Jun 28, 2020 | Posted by in NEUROLOGICAL IMAGING | Comments Off on 5 Cavum Septum Pellucidum
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