UMEM Educational Pearls

Title: Cerebral Venous Thrombosis - To Scan Or Magnetize?

Category: Neurology

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.

References

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

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