CEREBRAL VENOUS SINUS THROMBOSIS

Diagnosis of cerebral venous thrombosis

Created 07/04/2021, last revision 18/05/2022

  • especially in the initial stages, diagnosis is often difficult; the time course and symptoms are variable and non-specific
  • focal symptoms appear in association with the development of venous infarcts
  • conceive CVT in the presence of:
    • intracranial hypertension syndrome
    • ischemia, especially in atypical localization and with hemorrhagic component
    • first epileptic seizure (especially in younger women)
    • signs of thrombosis on NCCT

Neuroimaging

  • neuroimaging is essential to the diagnosis of CVT
  • CT is widely available and is the most common initial imaging
When to think about cerebral venous sinus thrombosis?
Direct signs of thrombus in the vein/dural sinus
dense clot sign (delta sign)   Dense clot sign (75HU) on NCCT - thrombosis of the right transverse sinus Dense clot sign (delta sign) - thrombosis of the superior sagittal sinus
cord sign Cord sign - thrombosis of the superficial cerebral veins
empty delta sign (contrast-enhanced CT) Empty delta sign on postcontrast CT scan
absent flow void in T2/FLAIR Absence of flow void in the left sigmoid sinus (FLAIR)
Indirect signs
  • lateral, parasagittal, bithalamic infarcts with/without hemorrhage  Hemorrhagic infarction in thrombosis of the left transverse and sigmoid sinus The straight sinus thrombosis with bithalamic venous infarction Venous infarction (NCCT)
  • cortical edema, peripheral lobar hematomas  Thrombosis of the left ascendent vein   Hemorrhagic venous infarction in thrombosis of transverse and superior sagittal sinus

CT + CT venography

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MRI + MR venography

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Digital subtraction angiography

  • think of potential anatomical variants of the venous system, including the hypoplasia or absence of some of the vessels
  • specific for CVST diagnosis is the “stop sign” (abrupt termination of a sinus or vein) with collateral circulation and congestion of cortical veins (dilatation, winding course)  The right transverse and sigmoid sinus thrombosis The superior sagittal sinus thrombosis on DSA
  • it can show associated thrombosis of cortical veins and possibly arterio-venous fistula and deep vein thrombosis
  • in addition, DSA shows the dynamics and drainage pattern in the occluded area
    • usually, the veins are displayed in 4-5 sec. after the application of the contrast agent; the venous system is completely displayed within 7-8 sec.
    • with thrombosis, the filling of the veins is delayed or absent
  • currently, MRV and CTV dominate the diagnostic workup, and DSA is preserved for interventional procedures when conservative therapy fails

Neurosonology

  • low sensitivity and specificity, the method may be suitable for treatment monitoring
  • we mainly evaluate indirect signs – flow acceleration (> 40 cm/s) due to collateral circulation
  • the sigmoid sinus (SS) thrombosis can be monitored by examining flow in the ipsilateral internal jugular veins (IJV) Occlusion of the right sigmoid sinus and IJV
  • TCCD examination of cerebral veins and sinuses → see here

Further diagnostic studies

D-dimers

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Lumbar puncture

  • perform lumbar puncture when an infectious etiology is suspected
  • CSF evacuation may relieve pain or prevent loss of vision (20-30 ml of CSF)
  • venous thrombosis tends to have a higher opening pressure, increased proteinorhachia, and sometimes mild pleocytosis
    • mild pleocytosis can lead to misdiagnosis of neuroinfection
  • lumbar puncture is contraindicated in the presence of an expansive parenchymal lesion

Other laboratory studies

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EEG

  • pathological findings tend to occur with parenchymal lesions
  • in case of altered mental status, exclude nonconvulsive status epilepticus (NCSE)

Differencial diagnosis

  • high-flow dural A-V fistula can lead to venous congestion with hemorrhagic infarction (which is difficult to distinguish from venous thrombosis)
  • headaches and encephalopathy are uncommon in ischemic stroke
  • infarct lesions in ischemic stroke and CVST differ in shape and localization
  • in CVST hemorrhagic transformation and collateral edema are frequent
  • seek signs of inflammation – fever, leukocytosis with ↑CRP and ↑ESR
  • positive CSF findings (pleocytosis, elevated protein level)
  • consider a combination of venous thrombosis and neuroinfection  (un such case, thrombosis is probably triggered by the infection)
  • typical symptoms and signs: headache, facial nerve palsy
  • exclude venous thrombosis (MRV/CTV)
  • symptoms not typical for IIH:
    • encephalopathy
    • focal neurological deficits
    • seizures
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