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.


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-performed contrast bolus timing in CT venogram, otherwise a premature acquisition after contrast administration may create a false impression of sagittal sinus enhancement.

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Article information

rID: 4451
Section: Signs
Synonyms or Alternate Spellings:

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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