Synonyms:
Cerebral venous thrombosis CVT or cerebral venous sinus thrombosis/dural sinus thrombosis CVST and also Cortical cerebral venous thrombosis:
Diagnosis:
By neuroimaging including CT venography, MR venography or catheter angiography revealing thrombus in the cerebral venous sinuses. May be clinically symptomatic or asymptomatic
Pathology:
Any combination of the following may be involved:
- Venous sinuses (sagittal sinus, torcula herephili, transverse sinus, straight sinus, sigmoid sinus, internal jugular vein, cavernous sinus)
- Deep veins
- Superficial (cortical) veins
- Note. in carvernous sinus thrombosis the vasavasorum of the ICA may be involved causing infarction in ICA territories, especially if due to infectious thrombosis
Clinical features:
- Headache, seizure, decreased consciousness
- Fluctuating symptoms
- Focal symptoms & signs including papilloedema
Findings on Investigations:
- LP: Raised opening pressure
MR venography MRV, (Time-of-flight TOF, contrast-enhanced MRV, Phase-Contrast PC MRV):
- Absence of filling in the sinus or veins
- Phase contrast MRV: shows flow only but not thrombus
- False positives occur in: Variant anatomy: high bifurcation of torcula, asymtrical bifurcation of torcula, atresia/hypoplasia of transverse sinus, arachnoid granulations
- TOF: flow gaps
MRI with contrast:
- Thrombus features:
- T1: Thrombus is initially isointense & hyperintense (methemoglobin) later on
- T2:- Thrombus is hypointense “pseudo flow void”, later on hyperintense (methemoglobin),
- FLAIR: Thrombus=hyperintense
- T2 gradient echo GRE: Thrombus= hypointese
- T1 +contrast: Clot= periclot enhancement early, all structures enhance later on.
- Brain parenchyma effects, oedema/Infarct /hemorrhage:
- DWI: may have hyperintense areas ADC map: high (vasogenic oedema) or low (cytotoxic oedema)
- T1: brain= hypointense & swollen, Hemorrhage that starts from the center of the lesion
- Venous infarcts: irregular edges
- T2: brain= hyperintense & swollen
- FLAIR: brain= hyperintense
- Gradient echo GRE: Brain= hypointense venous hemorrhage
- T1 +contrast: Brain= no enhancement, or patchy enhancement
Catheter angiography DSA:
- Occluded sinuses or Occluded cortical veins.
- Opacified draining veins. corkscrew appearance of rerouting veins.
- Enlarged collateral veins e.g. pterygoid veins
CT venogram CTV
- CT:
- Hemorrhagic infarction: irregular borders
- Hypodensity in one or both thalami (internal cerebral vein, straight sinus)
- Posterior temporal lobe oedema and petechial hemorrhage or large hemorrhage (transverse sinus, middle cerebral veins, vein of Labbe)
- Parasagittal lesion with superior sagittal sinus thrombosis
- Subarachnoid hemorrhage SAH blood over the cortex
- Thrombus: Hyperdensity in the sinus
- Delta sign (enhancement around a clot in the sagittal sinus)
- Cord sign= dense vessel sign= hyperdense veins e.g. in internal cerebral veins, cortical veins
- Prominent medullary veins: collateral circulation
- Hydrocephalus, hypodensity (venous infarction) with hemorrhagic conversion,
Investigations to consider:
- CT
- CTV or MRV
- LP: IIncreased opening pressure, Pleocytosis if septic
- Thrombophilia screen
- Monitor:
- No need for aggressively repeating imaging if no change in clincial status. However low threshold for imaging if clinical changes occur
Treatment:
Anticoagulation even if intracerebral hemorrhage is present [RCT of 20 patients, RCT 60 patients] :
- Heparin I.V.
- LMW heparin: enoxaparin, nadroparin or others
- Followed by warfarin for 3-6 months
If refractory consider endovascular therapy:
- Mechanical thrombectomy
- Local thrombolysis via venous approach