CEREBRAL VENOUS SINUS THROMBOSIS

Diagnosis of cerebral venous thrombosis

Created 07/04/2021, last revision 29/04/2023

  • diagnosis is often difficult in the initial stages; the time course and symptoms are variable and nonspecific
  • focal symptoms occur in association with the development of venous infarcts
  • exclude CVT in the presence of:
    • intracranial hypertension syndrome
    • atypical ischemia – especially with atypical localization, not respecting arterial territories, and with hemorrhagic component or edema
    • first epileptic seizure (especially in young women)
    • direct signs of thrombosis on NCCT

Neuroimaging

  • neuroimaging is essential for the diagnosis of CVT
  • CT is widely available and is the most commonly used baseline imaging modality
When should you 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, and 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

  • consider possible anatomical variants of the venous system, including 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 (dilation, tortuosity)  The right transverse and sigmoid sinus thrombosis The superior sagittal sinus thrombosis on DSA
  • it may show associated cortical veins thrombosis and possibly arterio-venous fistula and deep vein thrombosis
  • in addition, DSA shows the dynamics and drainage pattern in the occluded area
    • after applying the contrast agent, the venous system is completely visualized within 7-8 seconds
    • in thrombosis, the filling of the veins is delayed or absent
  • currently, MRV and CTV dominate the diagnostic workup, and DSA is reserved for interventional procedures when conservative therapy fails

Neurosonology

  • low sensitivity and specificity; the method may be suitable for treatment monitoring
  • we mostly 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
  • more about TCCD examination of cerebral veins and sinuses see here

Further diagnostic studies

D-dimers

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More about D-dimers

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Lumbar puncture

  • perform lumbar puncture if an infectious etiology is suspected
  • CSF evacuation may relieve pain or prevent loss of vision (20-30 ml of CSF)
  • typical signs of venous thrombosis include increased opening pressure, proteinorhachia, and sometimes mild pleocytosis
    • mild pleocytosis may 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 mental status is altered, rule out nonconvulsive status epilepticus (NCSE)

Differential diagnosis

Dural fistula

  • high-flow dural A-V fistula can lead to venous congestion with hemorrhagic infarction (which can difficult to distinguish from a venous thrombosis)

Ischemic stroke

  • headaches and encephalopathy are uncommon in ischemic stroke
  • infarct lesions in ischemic stroke and CVST differ in shape and location
  • in CVST, hemorrhagic transformation and collateral edema are common on baseline imaging

Encephalitis

  • look for signs of inflammation – fever, leukocytosis with ↑CRP and ↑ESR
  • positive CSF findings (pleocytosis, elevated protein level)
  • consider a combination of venous thrombosis and neuroinfection  (in such case, thrombosis is probably triggered by the infection)

Idiopathic intracranial hypertension (IIH)

  • 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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Diagnosis of cerebral venous thrombosis
link: https://www.stroke-manual.com/cerebral-venous-thrombosis-diagnosis/