Superior sagittal sinus thrombosis (SSST) is the most common type of dural venous sinus thrombosis and is potentially devastating.
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 haemorrhage 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 haemorrhage 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 oedema: secondary to venous hypertension
- cortical/cerebral swelling
- unilateral or bilateral venous haemorrhage
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 haematocrit and/or haemoglobin levels 5.
- 1. Schell CL, Rathe RJ. Superior sagittal sinus thrombosis. Still a killer. West. J. Med. 1988;149 (3): 304-7. Free text at pubmed - Pubmed citation
- 2. Lee EJ. The empty delta sign. Radiology. 2002;224 (3): 788-9. doi:10.1148/radiol.2243990978 - Pubmed citation
- 3. Virapongse C, Cazenave C, Quisling R et-al. The empty delta sign: frequency and significance in 76 cases of dural sinus thrombosis. Radiology. 1987;162 (3): 779-85. Radiology (abstract) - Pubmed citation
- 4. Nakase H, Takeshima T, Sakaki T et-al. Superior sagittal sinus thrombosis: a clinical and experimental study. Skull Base Surg. 1998;8 (4): 169-74. Free text at pubmed - Pubmed citation
- 5. Black DF, Rad AE, Gray LA et-al. Cerebral venous sinus density on noncontrast CT correlates with hematocrit. AJNR Am J Neuroradiol. 2011;32 (7): 1354-7. doi:10.3174/ajnr.A2504 - Pubmed citation