Empty delta sign (dural venous sinus thrombosis)

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, which represents 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.

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

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

'Δ' or delta is the name of the Greek letter with the sound of the English letter 'D' and clearly has a triangular shape. Hence river delta or delta-shaped wing.

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 acquisition 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.

Inspired signs

Article information

rID: 4451
Section: Signs
Synonyms or Alternate Spellings:

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Cases and figures

  • Fig 1: delta shaped wing of concorde
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  • Case 1: empty delta
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  • Case 2
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  • Case 3
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  • Case 4
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  • Case 5
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  • Case 8
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