How do you diagnose and manage suspected cerebral venous thrombosis (CVT)?

Diagnosing Cerebral Venous Thrombosis (CVT)

MRI with MR venography (MRV) is the preferred first-line imaging modality for diagnosing cerebral venous thrombosis, with CT venography (CTV) being a reasonable alternative when MRI is contraindicated or unavailable. 1

Diagnostic Approach to CVT

Initial Imaging

• When to suspect CVT: Consider in patients with:

  • Headache (most common symptom)
  • Focal neurological deficits
  • Seizures
  • Altered mental status
  • Risk factors: oral contraceptives, pregnancy/puerperium, thrombophilia, recent infection 2

• First-line imaging:

  • MRI with MRV - gold standard with highest sensitivity 1
    • Gradient echo T2 susceptibility-weighted images combined with MRV provide best diagnostic accuracy
    • Shows both thrombus and parenchymal changes
    • Contrast-enhanced MRV reduces flow artifacts

• Alternative imaging:

  • CT with CT venography (CTV) - when MRI is contraindicated or unavailable 2, 1
    • Approximately 87% accuracy for detecting intracranial complications
    • Faster acquisition time (5-10 minutes vs. longer for MRI)
    • More readily available in emergency settings

Key Imaging Findings

MRI/MRV Findings

• Absence of flow void in the sinus
• T2 hypointensity suggesting thrombus
• Central isodense lesion with surrounding enhancement ("empty delta" sign equivalent) 2
• Signal evolution over time:
  • Acute: Isointense on T1, hypointense on T2 (deoxyhemoglobin)
  • Subacute (1-2 weeks): Hyperintense on T1 and T2 (methemoglobin)
• Parenchymal changes correlate with specific sinus involvement 2, 1

CT/CTV Findings

• Non-contrast CT often normal (abnormal in only 30% of cases)
• Hyperdense dural sinus in acute thrombosis
• "Empty delta" sign on contrast-enhanced CT
• Mixed density within venous sinuses on CTV:
  • High-density contrast in patent segments
  • Low density in thrombosed segments 2, 1

Advanced or Confirmatory Testing

• Cerebral angiography: Reserved for:

  • Inconclusive MRV/CTV results with high clinical suspicion
  • Cases where endovascular treatment is being considered
  • Suspected isolated cortical vein thrombosis 2, 1

• Direct cerebral venography: Typically performed during endovascular procedures 2

Diagnostic Pitfalls and Considerations

Common Challenges

• Anatomic variants can mimic thrombosis:

  • Asymmetrical lateral (transverse) sinuses (present in 49% of normal population)
  • Prominent arachnoid granulations
  • Intrasinus septa 1

• Flow-related artifacts on MRV:

  • Slow flow can mimic thrombosis
  • Contrast-enhanced MRV helps reduce these artifacts 1

• Deep venous system evaluation:

  • Junction of straight sinus and vein of Galen may appear absent on TOF MRI if image acquisition is in axial plane
  • Overcome with contrast-enhanced MRI and DWI 2

Follow-up Imaging

• Early follow-up CTV or MRV recommended for:

  • Persistent or evolving symptoms despite treatment
  • Symptoms suggesting thrombus propagation 1

• Follow-up imaging at 3-6 months to assess recanalization in stable patients 1

Comparative Advantages of Imaging Modalities

CT+CTV	MRI+MRV
Quick (5-10 min)	Better visualization of superficial and deep venous systems
Readily available	Superior detection of early ischemic changes
Fewer motion artifacts	No radiation exposure
Usable with pacemakers/claustrophobia	Better detection of cortical and deep venous thrombosis
	Superior detection of micro/macrobleed

Management After Diagnosis

• Initiate anticoagulation with either:
  • Intravenous unfractionated heparin, or
  • Subcutaneous low molecular weight heparin
• Continue anticoagulation even in presence of hemorrhagic changes 1
• Consider endovascular therapy for severe cases or patients who fail to improve on anticoagulation 1

By following this diagnostic approach, CVT can be identified early, allowing for prompt treatment and improved outcomes for patients with this potentially serious condition.