What is the recommended diagnosis and treatment for cerebral venous thrombosis (CVT)?

Cerebral Venous Thrombosis Diagnosis

For suspected cerebral venous thrombosis (CVT), a venographic study using either CT venography (CTV) or MR venography (MRV) should be performed, even if initial plain CT or MRI is negative, as these are essential for definitive diagnosis. 1

Diagnostic Approach

Initial Imaging

• Plain CT or MRI is useful for initial evaluation but cannot rule out CVT
• MRI with MRV is the preferred imaging modality for diagnosing sinus thrombosis 2
  • Can detect both thrombus and associated parenchymal changes
  • Contrast-enhanced MRV reduces flow artifacts
  • Gradient echo T2 susceptibility-weighted images combined with MR significantly improve diagnostic accuracy 1

When MRI is Not Available

• CT with CT venography (CTV) is a reasonable alternative 2
  • Approximately 87% accuracy for detecting intracranial complications
  • Provides detailed anatomical information and can identify thrombus extension
  • Useful for planning revascularization if needed

Key Imaging Findings

MRI Findings

• Signal varies over time:
  • Acute phase: Hypointense in T2*, while T1 and T2 can appear falsely reassuring 3
  • Subacute phase: Hyperintense on all sequences (T1, T2, FLAIR, T2*, diffusion) 3
• Parenchymal changes correlate with specific sinus involvement:
  • Frontal, parietal, occipital lobe changes: Superior sagittal sinus thrombosis
  • Temporal lobe changes: Lateral (transverse) and sigmoid sinus thrombosis
  • Deep parenchymal abnormalities (thalamic hemorrhage, edema): Vein of Galen or straight sinus thrombosis 1

CT Findings

• Direct signs: Cord sign or empty delta sign (seen in only about 25% of cases) 4
• CTV shows mixed density within venous sinuses:
  • High-density contrast in patent segments
  • Low density in non-perfusing thrombosed segments 1

Follow-up Imaging Recommendations

1. Early follow-up CTV or MRV is recommended for:

   • Patients with persistent or evolving symptoms despite medical treatment
   • Symptoms suggesting thrombus propagation 1

2. In patients with previous CVT who present with recurrent symptoms, repeat CTV or MRV is recommended 1

3. Follow-up CTV or MRV at 3-6 months after diagnosis is reasonable to assess recanalization of the occluded cortical vein/sinuses in stable patients 1, 2

Potential Diagnostic Pitfalls

Anatomic Variants That May Mimic CVT

• Asymmetrical lateral (transverse) sinuses (present in 49% of normal population)
• Partial or complete absence of one lateral sinus (20% of normal population)
• Normal sinus filling defects related to prominent arachnoid granulations or intrasinus septa 1

Flow-Related Artifacts

• Flow gaps commonly seen on TOF MRV images
• 2D TOF technique has excellent sensitivity to slow flow compared with 3D TOF but has potential pitfalls 1

When to Consider Advanced Imaging

Catheter cerebral angiography should be considered in:

• Patients with inconclusive CTV or MRV but high clinical suspicion for CVT 1
• Cases where endovascular treatment is being considered 2

Diagnostic Algorithm

1. Clinical suspicion of CVT
2. MRI with T2*-weighted imaging + MRV (first choice)
   • OR CT/CTV if MRI not readily available
3. If imaging confirms CVT → proceed to treatment
4. If initial imaging is negative but clinical suspicion remains high → consider:
   • Alternative MRI sequences (contrast-enhanced MRI)
   • Catheter cerebral angiography in selected cases

The diagnosis of CVT requires a high index of clinical suspicion and appropriate neuroimaging. While contrast-enhanced techniques are more accurate than non-contrast techniques 5, the choice between CTV and MRI depends on availability, local expertise, and patient characteristics.

Remember that headache is the most common presenting feature (60% of cases) 4, and prompt diagnosis and treatment are essential to reduce morbidity and mortality in this potentially life-threatening condition.