Dural arteriovenous fistula& AV malformation

Dr.Aftab Qadir

Vascular malformations involving the brain are divided into• arteriovenous malformations (AVM)• developmental venous anomalies (DVA)• cavernous malformations • capillary telangiectasia.

Angiography

• Selective : evaluation of AVM and entire cerebral circulation

• Super selective : Microcatheters advanced into distal aspect of arterial feeders to study anatomical structure

Angiography

• Demonstrating the nidus• Multiple arterial feeders• Thrombosed dural sinus• Flow reversal in sinus and cortical vein

• Arterial territories supplying the AVM• Feeding pedicles • High flow arteriopathy(stenose,ectasia,aneyrysm)• Venous drainage(territories,deep,superficial)• Individual draining veins• High flow venous angiopathy (dural sinuses,venous

stenoses,occlusions )• Venous drainage of normal brain parenchyma

Goals selective angiography

Nidus

• Fistulous-Large calibre direct AV connection

• Plexifom-conglomerulate of multipe small vascular channels supplied by one or more arterial feeders and draining veins

Dural arteriovenous fistula

• Dural arteriovenous fistulas (AVF) are pathologic abnormal vascular connections between dural arteries with the venous sinuses or cortical veins

Schematic overview of the Borden system of classification for DAVFs

Location

• transverse / sigmoid sinus most common• cavernous sinus (indirect caroticocavernous fistula) • superior sagittal sinus• straight sinus• other venous sinuses• anterior cranial fossa• tentorium

Clinical presentation

• Pulsatile tinnitus• cranial nerve palsies• orbital symptoms• raised intracranial pressure• focal neurological deficits

Complications

• haemorrhage• subdural haemorrhage (SDH)• intracranial haemorrhage (ICH)• subarachnoid haemorrhage (SAH)• intracranial hypertension• venous congestion and oedema

Imaging

a) CT scan

b) MRI

c) Cerebral angiogram

CT

• NECT: usually normal

• CECT: Normal /small tortous dural feeders Enlarged dural sinuses

Enlarged superior opthalmic vein in CCF Enlarged cortical draining veins

Curvilinear subcortical calcifications

Curvilinear subcortical calcifications can be seen at CT in patients with long-standing cortical venous reflux, possibly due to chronic venous congestion

MRI

• TIWI and T2WI- Flow voids and thrombosed sinus• T2 & Flair-Hyperintensities due to venous

congestion/ischemia• T1C+ diffuse dural enhancement• MRV- Occluded sinus and collateral flow• 3D PC MRA with low velocity encoding- identify

feeding arteries,fistula and flow reversal in draining veins

Angiography

• Subtraction selective angiography of internal and external cartotid arteries or both

-dAVF second most common site

-Abnormal communication between carotid artery & cavernous sinus-Shunt between the meningeal branches of internal or external carotid and dural veins near the cavernous sinus

Carotid Cavernous Fistula (CCF)

CT & MRI

CT:• – Marked dilation & enhancement of cavernous sinus• – May see prominent SOV

MRI:• – Abnormal flow voids in cavernous sinus• – Enlargement of cavernous sinus

AVM

• Brain arteriovenous malformations (AVMs) are abnormal vascular connections within the brain that are congenital

Diagnostic criteria:• Presence of nidus • early venous drainage

High and Low flow malformations

High flow• arteriovenous malformation (AVM)• parenchymal AVM• dural arteriovenous fistula (DAVF)• mixed AVM

Low flow• capillary telangiectasia• cavernous haemangioma• venous malformations• developmental venous anomaly (DVA) (venous angiomas)• vein of Galen malformation (can be high flow as well)

CT

• NECT:Iso/Hyperdense serpentine vessels• calcificationin 25-30%• Variable hemorrahage• CECT: Strong enhancement

MRI

• Variable• Punctate appearance on T2 due to single void• Large arteries and veins are characteristic• Intracerebral hematoma with high signal on T1• Surrounding halo –hyposignal on T2 indicating

hemosidrren• Post contrast not facilitate detactability like CECT

VEIN OF GALEN MALFORMATION

• Arteriovenous fistula involving a neurysmal dilatation of median prosencephalic vein (MPV)

• Most common extracardiac cause of high-output congestive heart failure in newborns

• < 1% of cerebral vascular malformations

Venous angiomas

• aberrant venous drainage of one or both cerebral hemispheres.

• They are shown on MRI as a slightly curvilinear structure traversing cerebral substance, representing a single draining vein into which numerous cerebral veins converge.

• They are often incidental findings, but may be associated with (parenchyma) haemorrhage or focal brain damage

Telangiectasia

• Shown on MRI as small lesion• Hypointense on T1• T1 C+ (GAD) : may demonstrate ill defined focal

enhancement• Hyperintense on T2

cavernous hemangioma

• Slow flow lesions• Accounts for 10-15%• No intervening brain• No mass effect on imaging• CT usually normal if small

lesion or in absence of calciication and hemorrgage

• Characteristic feature is hypointense rim because of hemosiderin

Few case

15-year-old boy who presentedwith sudden onset of headaches followed by seizures

Thank You