Dural Arteriovenous Fistula, Cranial

Diseases,

Clinical features:

  • Wide range including: asymptomatic, pulsatile tinnitus, headache, cranial nerve palsy, cognitive deficits, hydrocephalus, focal deficits, seizures\
  • Pulsatile tinnitus, pulsatile exophthalmos
  • Cranial neuropathy
  • Encephalopathy, dementia, Parkinsonism
  • In neonates/infants: heart failure

Diagnosis:

Catheter Angiogram:

  • Use superselective catheterisation of 4 vessels, +external carotid
  • Abnormal arteries and veins with shunting contained entirely within the dura (dural leaflets)
  • Multiple feeding arteries are usually present. Usually external carotid artery.
  • Early opacification of venous structures after dye administration. Flow reversal in veins may occur. Cortical drainage is associated with poor prognosis (high rupture rate).
  • Associated with thrombosed venous sinus (especially transverse & cavernous) or with the tentorium.
  • Named based on involved dural sinus.

Pathology:

  • Direct connection between artery and vein (pial vein i.e. cortical vein or dural sinus) without capillaries or nidus
  • Venous drainage may be directly into the dural sinus or via pial veins “cortical vein”
  • Feeding arteries are usually branches of the extracranial carotid artery but ICA and VA meningeal branches may supply the fistula. Dural arteries supply dural AVFs.
  • May cause infarct, hemorrhage, venous thrombosis, cranial nerve palsy

Findings on Investigations:

CT:

  • May be normal
  • Enhancement: may be normal or show enlarged arterial feeder, enlarged sinus or enlarged vein

CTA:

  • False negatives occur
  • Shows some of the angioarchitecture

MRI:

  • False negatives occur
  • T1: normal or abnormal vessels or thrombosed sinus
  • T2: flow voids, Retrograde leptomeningeal venous drainage (hyperintensity in adjacent brain)
  • FLAIR: thrombosed sinus, +/-brain oedema,
  • GRE: normal or hemorrhage
  • DWI: normal or restricted in infarct
  • Enhancement: enhanced thromosed sinus

MRA:

  • False negatives occur
  • TOF
  • Contrast enhanced TOF MRA may show detail

MRV:

  • False negatives occur
  • Thrombosed sinus
  • Flow reversal in draining veins

DSA, catheter angiography: perform ECA, ICA, VA injections

Classifications:

Sites (6-7 locations):
  • Transverse and sigmoid sinus DAVF
  • Torcula herophili DAVF (considered by some subtype of transverse sinus DAVF)
  • Cavernous sinus, indirect CCF
  • Superior sagittal sinus DAVF
  • Ethmoidal (anterior fossa) DAVF
  • Tentorial DAVF
  • Foramen magnum DAVF
Sites (feeders & drainage in detail):

Transverse and sigmoid sinus DAVF:

  • Typical arterial feeders:
    • ECA branches: occipital a., APhA, MMA, (unilateral or bilateral)
    • Sometimes: Meningeal ICA (cavernous segment) branches, meningeal VA branches
  • Typical venous drainage:
    • Transverse sinus
    • Typical pial vein involvement:
    • None or minimal

Torcula herophili DAVF (considered by some subtype of transverse sinus DAVF):

  • Typical arterial feeders:
    • ECA branches: occipital a., APhA, MMA, (unilateral or bilateral)
    • Sometimes: Meningeal ICA (cavernous segment) branches, meningeal VA branches or cerebellar pial arteries
  • Typical venous drainage:
    • torcula herophili. But if thrombosed, then to straight sinus to vein of Galen to basal vein of Rosenthal then to deep cerebral veins +venous congestion
    • Typical pial vein involvement:
    • none, but congestion in deep cerebral and cerebellar veins

Cavernous sinus, indirect CCF:

  • Typical arterial feeders:
    • Distal IMA, APhA, MMA, cavernous ICA branches (uni- or bi-lateral)
    • Rarely only ECA or ICA branches
  • Typical venous drainage:
    • Variable: one or both of the patterns below:
    • Superior & inferior ophthalmic veins if anterior fistula
    • Inferior petrosal sinus & superior petrosal sinus if posterior fistula
  • Typical pial vein involvement:
    • Usually none
    • directly to Superficial & deep middle cerebral veins, or via paracavernous sinus via connection with pterygoid plexus
    • to bridging vein to ponto-mesencephalic vein to peduncular vein to Basal vein of Rosenthal
    • to Superior petrosal sinus to petrosal vein to lateral mesencephalic vein to basal vein of Rosenthal
    • to petrosal vein to cerebellar veins

Superior sagittal sinus DAVF:

  • Typical arterial feeders:
    • ECA branches: MMA (often bilaterally), Superficial temporal artery (transosseous), Occipital artery (transosseous)
    • Occasionally: Ophthalmic supply (Anterior meningeal artery), VA meningeal branches
  • Typical venous drainage:
    • Typical pial vein involvement: long tortuous pial cortical veins

Ethmoidal (anterior cranial fossa) DAVF:

  • Typical arterial feeders:
    • Ophthalmic artery branches (Anterior and posterior ethmoidal arteries, anterior meningeal artery), anastomosis with internal maxillary artery IMA (IMA ethmoidal branches from sphenopalatine artery)
  • Typical venous drainage: cortical veins to Superior sagittal sinus. Uncommonly to the cavernous sinus.
  • Typical pial vein involvement: cerebral veins (frontal convexity veins)

Tentorial DAVF:

  • Anterior (petrotentotial), posterior (ie. Posterior or lateral) subtypes
  • Typical arterial feeders:
    • Many feeders: ECA (MMA branches), artery of foramen rotundum, Occipital artery, APhA. Cavernous ICA branches. SCA (Leptomeningeal branches).
    • In posterior subtype same arterial feeders +more SCA, PCA branches, artery of the falx cerebelli. Also +meningeal branch of PCA
  • Typical venous drainage:
    • Petrosal vein then mesencephalic vein, then posterior mesencephalic vein then vein of Galen then straight sinus. If thrombosed, then to Basal vein of Rosenthal, then to internal cerebral vein.
    • In posterior subtype: very variable, same as anterior +transverse sinus, superior sagittal sinus,
  • Typical pial vein involvement: cerebellar and cerebral (occipital) especially in posterior subtype

Foramen magnum DAVF:

  • Typical arterial feeders:
    • APhA (uni-or bilaterally), Occipital artery, VA. Rarely internal maxillary artery or ICA branches.
  • Typical venous drainage: variable, inferior petrosal sinus, jugular vein, sigmoid sinus, anterior condylar vein, marginal sinus
  • Typical pial vein involvement: brainstem veins, Spinal perimedullary venous drainage
Cognard classification (intracranial dAVF):

Type I:

  • AVF in sinus wall, antegrade flow
  • Benign course

Type IIA:

  • AVF in main sinus, reflux into sinus, no reflux into cortical veins

Type IIB:

  • Reflux into cortical veins
  • High hemorrhage rate

Type III:

  • Direct cortical drainage, no venous ectasia
  • High hemorrhage rate

Type IV:

  • Direct cortical drainage, +venous ectasia
  • High hemorrhage rate

Type V:

  • Spinal perimedullary venous drainage

See classification of spinal vascular lesions separately
 

Classification (Borden):

Type 1:

  • Shunting into dural sinus (or meningeal vein) with only antegrade flow

Type 2:

  • Shunting into dural sinus (or meningeal vein) with retrograde flow into subarachnoid veins

Type 3:

  • Direct shunting into subarachnoid veins without dural drainage
    Each may be subtype A (single hole), subtype B (multiple holes)

Treatment:

Observation, endovascular (venous or arterial approach), surgical or combined treatment
Transverse and sigmoid sinus dAVF:

  • Usually endovascular (arterial or venous approach). Consider surgery if thrombosis has caused an isolated sinus.

Cavernous sinus (indirect CCF):

  • Consider Carotid-jugular compression for diagnosis if not contraindicated
  • Usually endovascularly via venous approach
  • Arterial approach via external carotid artery
  • Venous approach via jugular vein and inferior petrosal sinus
  • Venous approach via facial vein & superior orbital vein

Superior sagittal sinus dAVF:

  • Usually surgically
  • Embolization is sometimes possible.

Ethmoidal (anterior cranial fossa) dAVF:

  • Usually surgically

Tentorial dAVF:

  • Difficult. Usually endovascular +/-surgery

Foramen magnum dAVF:

  • Usually Surgically

Torcula herophili DAVF:

  • Endovascular option:
    • Embolization via arterial route: Onyx or glue
      Or if at least one transverse sinus is open, transvenous embolization with coils
  • Surgical excision vs. endovascular embolization

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