CASE 14794 Published on 12.06.2017
0

Brain herniation into dural venous sinus

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Jose Alejandro Bacalla MD, Angel Donato MD, Ramon Figueroa MD

Augusta University
1120 15th street
Augusta, GA 30912
USA
E-mail: josealejandrobv@gmail.com
Connected authors
Patient

31 years, male

Categories
Area of Interest Neuroradiology brain, Vascular ; Imaging Technique MR, CT
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Clinical History
31-year-old male patient involved in a motor vehicle accident evaluated for head trauma.
Imaging Findings
CT shows a heterogeneous oval-shaped abnormality within the distal right transverse sinus (Fig. 1).
MRI demostrates a polyploid cortical herniation from the lateral inferior right temporal occipital cortex into the superior aspect of the right transverse sinus within a large arachnoid granulation, in keeping with an internal encephalocoele. (Fig. 2 and 3).
MR venogram shows a bifid right transverse sinus enclosing a large arachnoid granulation, an anatomic variant (Fig. 4).
Discussion
Brain herniation into dural venous sinus, according to Battal et al [1], have a prevalence of 0.32% . Its pathophysiology and clinical significance is still controversial, being a recently described entity best depicted by MRI. It is yet unclear whether it represents true brain herniation into a dural defect or brain tissue getting into a pre-existing giant arachnoid granulation. In most cases it is not pathologically possible to identify arachnoid tissue next or around the herniation, but some authors postulate that arachnoid granulation predispose to its occurrence. Cohan et al [2] called it "occult encephaloceles" because they do not cross any dura o bony defects as classic encephaloceles do. The theory that brain herniations result from increased intracranial pressure is not widely accepted, since they have been found in patients with no signs of increased intracranial pressure.

There is no clear association between clinical symptoms and brain herniations or large arachnoid granulations. Although headaches and dizziness are mentioned occasionally, most described lesions have been incidental findings not related to any pathology [2].

From the imaging point of view, 3D T1- and T2-weighted sequences are most useful in characterising herniated brain, its continuity with adjacent brain parenchyma and CSF-containing compartments. These sequences allow the radiologist to identify the CSF outlining the brain parenchyma. The occipital squama, transverse sinus, lateral lacuna of the superior sagittal sinus, and straight sinus are the most frequent sites for their appearance, with cerebellar tissue being the most frequently involved in brain herniation [3].

On MR venography or venous phase DSA, round focal filling defects are identified, usually not obstructing the dural sinuses.

It is important to make the differentiation from dural sinus venous thrombosis, which usually reveal multiple and irregular filling defects, and from dural-based tumours (showing enhancement and diffusion restriction). Uncomplicated giant arachnoid granulation may also have similar appearance.

Brain herniation into a dural venous sinus most likely is an incidental findings with not enough supporting evidence of their clinical significance. Given the increasing amounts of MR studies being performed, they are more frequently found and should be differentiated from more ominous dural sinus pathology.
Differential Diagnosis List
Brain herniation into dural venous sinus.
Dural venous sinus thrombosis
Dural-based tumour
Giant arachnoid granulation
Final Diagnosis
Brain herniation into dural venous sinus.
Case information
URL: https://www.eurorad.org/case/14794
DOI: 10.1594/EURORAD/CASE.14794
ISSN: 1563-4086
License

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Figure 1

CT head

CT head
Nonspecific heterogeneous lesion centred within the right posterior fossa at the level of the distal transverse sinus.
CT head
Nonspecific heterogeneous lesion centred within the right posterior fossa at the level of the distal transverse sinus.
CT head
Nonspecific heterogeneous lesion centred within the right posterior fossa at the level of the distal transverse sinus.
CT head
Nonspecific heterogeneous lesion centred within the right posterior fossa at the level of the distal transverse sinus.
Figure 2

MR Venogram

MR Venogram
MR Venogram shows a bifid right transverse sinus enclosing the "sac" of the brain herniation. The sigmoid sinus and the internal yugulary vein are normal in calibre.
MR Venogram
MR Venogram shows a bifid right transverse sinus enclosing the "sac" of the brain herniation. The sigmoid sinus and the internal yugulary vein are normal in calibre.
MR Venogram
MR Venogram shows a bifid right transverse sinus enclosing the "sac" of the brain herniation. The sigmoid sinus and the internal yugulary vein are normal in calibre.
Figure 3

MRI Axial T1,T2, FLAIR, T1-postc.

MRI Axial T1,T2, FLAIR, T1-postc.
MRI demostrates a polypoid cortical herniation from the lateral inferior right temporal occipital cortex into the superior aspect of the right transverse sinus in keeping with brain herniation into the tranverse sinus.
MRI Axial T1,T2, FLAIR, T1-postc.
MRI demonstrates that the cortical herniation is sorrounded by CSF.
MRI Axial T1,T2, FLAIR, T1-postc.
MRI demostrates a polypoid cortical herniation from the lateral inferior right temporal occipital cortex into the superior aspect of the right transverse sinus in keeping with brain herniation into the tranverse sinus.
MRI Axial T1,T2, FLAIR, T1-postc.
MRI demostrates a polypoid cortical herniation from the lateral inferior right temporal occipital cortex into the superior aspect of the right transverse sinus in keeping with brain herniation into the tranverse sinus.
Figure 4

MRI Coronal T1 and T1-post-contrast.

MRI Coronal T1 and T1-post-contrast.
MRI demostrates a polypoid cortical herniation from the lateral inferior right temporal occipital cortex into the superior aspect of the right transverse sinus.
MRI Coronal T1 and T1-post-contrast.
MRI demostrates a polypoid cortical herniation from the lateral inferior right temporal occipital cortex into the superior aspect of the right transverse sinus.
MRI Coronal T1 and T1-post-contrast.
MRI demostrates a polypoid cortical herniation from the lateral inferior right temporal occipital cortex into the superior aspect of the right transverse sinus.
MRI Coronal T1 and T1-post-contrast.
MRI demostrates a polypoid cortical herniation from the lateral inferior right temporal occipital cortex into the superior aspect of the right transverse sinus.