Superior sagittal sinus thrombosis

Dr Craig Hacking and A.Prof Frank Gaillard et al.

Superior sagittal sinus thrombosis (SSST) is the most common type of dural venous sinus thrombosis and is potentially devastating.

This article focuses on the specific features related to the superior sagittal sinus thrombosis, please refer to the dural venous sinus thrombosis article for a general discussion. 

Risk factors include pregnancy, dehydration, hypercoaguable states, pancreatitis. 

As with all cerebral venous thrombosis, the presentation is highly variable, ranging from completely asymptomatic to a rapid fulminant course with cerebral hemorrhage and death. Presentation includes:

  • headache: 53%, most common 1
  • seizures: 48%
  • hemi-, quadri-, or paraplegia: 48%
  • visual disturbances: 25%
  • nuchal rigidity: 18%

Features are the same as those for other sinuses (please refer to dural venous sinus thrombosis).

Unenhanced CT is usually the first imaging investigation performed given the nonspecific clinical presentation in this cases. When not associated with venous hemorrhage or infarction, it can be a subtle finding on CT images, relying on hyperdensity of the sinus being identified. Potential findings include:

  • cord sign
  • dense vein sign
    • a potential pitfall is interpreting the distal superior sagittal sinus as being hyperdense near the torcular herophili
    • the walls at this location can be thick, measuring up to 2-3 mm
  • cerebral edema: secondary to venous hypertension
  • cortical/cerebral swelling
  • unilateral or bilateral venous hemorrhage

With contrast administration, especially with a CT venogram, then a filling defect in a sinus is sought. Multiplayer reformatted CT venography has been reported with a sensitivity of 95% for this diagnosis 4. When in the superior sagittal sinus it is referred to as the empty delta sign. Signs on contrast CT include:

  • empty delta sign (is a specific to the superior sagittal sinus)
  • gyral enhancement
  • prominent intramedullary veins

The clot acutely is isodense on T1 and hypointense on T2 (this can mimic a flow void), with subacute clot becoming hyperintense on T1. All the findings listed in the CT section are also seen on MRI. MRV will demonstrate lack of flow.

For high attenuating cerebral veins on a noncontast CT scan consider, high hematocrit and/or hemoglobin levels 5.

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Article information

rID: 6517
Synonyms or Alternate Spellings:
  • Thrombosis of the superior sagittal sinus
  • Superior sagittal sinus (SSS) thrombosis
  • Superior sagittal sinus thrombosis (SSST)

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Cases and figures

  • Fig 1: illustration - superior sagittal sinus
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  • Case 1
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  • Superior sagittal...
    Case 2: T2
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  • Superior sagittal...
    Case 2: T1
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  • Case 3
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  • Cerebral venous i...
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  • Case 5
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