Empty delta sign

The empty delta sign is a CT sign of dural venous sinus thrombosis of the superior sagittal sinus, where contrast outlines a triangular filling defect (thrombus). It is only described with CECT-scan or MRI, not with NECT nor non-contrast MRI.

An equivalent appearance can be noted in the transverse sinus on sagittal or coronal planes.

Pathology

The exact mechanism for this appearance is uncertain, with possibilities including:

  • recanalisation around an organising clot
  • enlargement of the peridural small veins: a vascular mesh (dural cavernous spaces), and meningeal venous tributaries
  • thickening of the dura with increased enhancement

Practical points

Caution must be taken to achieve a well timed acquisition in CT cerebral venography, particularly in cases of intracranial hypertension which can cause delayed filling of the venous sinus.  A premature acquisiton may create a false impression of thrombosis, which is simply due to contrast not yet reaching the venous sinuses.  The cerebral veins should also be opacified on a CT cerebral venogram, and if they are not, one should suspect premature acquisition.

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Article information

rID: 4451
Section: Signs
Synonyms or Alternate Spellings:

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Cases and figures

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    Fig 1: delta shaped wing of concorde
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    Case 1: empty delta
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    Central filling d...
    Case 2
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    Case 3
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    Dural venous sinus thrombosis
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    Dural venous sinus thrombosis
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