MRV Imaging for Suspected CVST

Optimal Imaging Protocol

The American College of Radiology recommends that for suspected cerebral venous sinus thrombosis, MRV should be ordered both without and with IV contrast, as the combination of time-of-flight (TOF) and contrast-enhanced MRV provides the highest diagnostic accuracy 1, 2
The ideal MRV protocol includes both non-contrast TOF and contrast-enhanced sequences performed together, as recommended by the American College of Radiology 1, 2
Contrast-enhanced MRV is the most accurate single technique for CVST diagnosis, but has a critical limitation: T1 isointense thrombus can mimic normal sinus opacification, leading to false negatives 1, 2
TOF MRV mitigates against this pitfall by detecting T1 isointense thrombus that would be missed on contrast-enhanced imaging alone 1, 2
Contrast-enhanced MRV better evaluates hypoplastic sinuses with slow flow, which can appear falsely thrombosed on TOF sequences 1, 2
T1 hyperintense thrombus can mimic normal flow patterns, making non-contrast MRI sequences essential for accurate interpretation 1, 2

The 2024 ACR Appropriateness Criteria explicitly state that MRV "ideally consists of both noncontrast TOF and contrast-enhanced MRV" because these techniques are complementary 1, 2

The American Heart Association/American Stroke Association guidelines recommend that a venographic study (either CTV or MRV) should be performed in suspected CVT, and emphasize that lack of thrombus identification on contrast-enhanced MRV helps clarify diagnosis 3, 4, 5, 6
Adding gradient echo T2 susceptibility-weighted imaging to improve diagnostic accuracy is a Class IIa recommendation 3, 4, 5, 6
Volumetric MRI sequences are essential for contrast-enhanced MRV, and delayed post-contrast imaging can further increase sensitivity for T1 isointense thrombus 1, 2

Flow gaps are commonly seen on TOF MRV and can be misinterpreted as thrombosis in normal anatomic variants (49% have asymmetrical transverse sinuses, 20% have partial/complete absence of one lateral sinus) 3, 4, 5, 6
Never rely on plain MRI alone—a negative plain MRI does not rule out CVST (Class I recommendation) 3, 4, 5, 6
Sinus signal-intensity variations affect interpretation, making the combination of sequences critical for accurate diagnosis 3, 4, 5, 6
If MRV remains inconclusive despite optimal imaging, catheter cerebral angiography is reasonable (Class IIa recommendation) 3, 4, 5, 6

The American Heart Association/American Stroke Association recommends that a venographic study (either CTV or MRV) should be performed in suspected CVT cases (Class I recommendation) 7, 8
Early follow-up CTV or MRV is recommended in CVT patients with persistent or evolving symptoms despite medical treatment or with symptoms suggestive of thrombus propagation (Class I recommendation) 7, 8
Follow-up imaging at 3 to 6 months after diagnosis is reasonable to assess for recanalization of occluded cortical veins/sinuses in stable patients (Class IIa recommendation) 7, 8

A negative plain CT or MRI does not rule out CVT—a venographic study must be performed if clinical suspicion remains (Class I recommendation) 7, 8
The American College of Cardiology is not mentioned in this context, however, the American Heart Association/American Stroke Association explicitly states the use of CTV or MRV for diagnosing cerebral venous thrombosis 7, 8

In young to middle-aged women with CVT risk factors, MRV is the preferred modality due to its superior sensitivity and lack of radiation exposure 7, 8
Adding gradient echo T2 susceptibility-weighted imaging to the MRV protocol further improves diagnostic accuracy (Class IIa recommendation) 7, 8
If both MRV and CTV remain inconclusive despite optimal imaging protocols and clinical suspicion for CVT remains high, catheter cerebral angiography is reasonable (Class IIa recommendation) 7, 8