UMEM Educational Pearls

Category: Neurology

Title: Cerebral Venous Thrombosis - To Scan Or Magnetize?

Keywords: cerebral venous thrombosis, CVT, venography, CTV, MRV (PubMed Search)

Posted: 2/10/2016 by WanTsu Wendy Chang, MD
Click here to contact WanTsu Wendy Chang, MD

Cerebral Venous Thrombosis - To Scan Or Magnetize?
  • 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.


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


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