UMEM Educational Pearls

• Cerebral venous thrombosis (CVT) is a rare but potentially life-threatening disease.
• Mortality in CVT is largely attributed to herniation.
• The diagnosis of CVT is made on the basis of clinical presentation and imaging studies.
• When you are concerned about CVT in a patient, which neuroimaging modality should you obtain?  CT or MRI?
• Non-contrast CT
  • Often the first neuroimaging obtained as it can evaluate for other processes such as cerebral infarct, intracranial hemorrhage, and cerebral edema.
  • Dense delta sign, dense clot sign and cord sign all refer to hyperattenuation of the clot. 
  • However, these findings are only seen in 20-25% of cases and disappear within 1-2 weeks.
• MRI
  • Clot appears hyperintense in the subacute phase.
  • In the acute phase, clot can mimic normal venous flow signal and result in potential diagnostic error.
• CT venography
  • Detailed depiction of cerebral venous system.
  • Timing of contrast bolus affect quality of evaluation.
  • Reconstruction may be difficult to subtract all of the adjacent bone.
• MR venography (MRV)
  • Unenhanced time-of-flight (TOF) MR venography has excellent sensitivity to slow flow.  It is useful in detection of large occlusions (e.g. jugular venous thrombosis), but susceptible to flow artifacts.
  • Contrast enhanced MR venography improves visualization of small vessels, thus preferred to TOF MR venography.

Bottom Line:  CT venography is good for diagnosing CVT, but MRI/MRV is superior for detection of isolated cortical venous thromboses and assessing parenchymal damage.

References

Bonneville F. Imaging of cerebral venous thrombosis. Diagn Interv Imaging. 2014;95:1145-1150.

 

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