avm - smith (rsna 2010)

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AVM - Smith (RSNA 2010)


Vascular Malformations: Brain

Vascular Malformations Arteriovenous malformation (AVM) Shunt Mixed Malformation Developmental venous anomaly = Combo (DVA) No Cavernous malformation Shunt Capillary telangiectasia Classic Dural arteriovenous fistula (dAVF) Vein of Galen Malformation (VOG)

Alice Boyd Smith, MD Chief, Neuroradiology Department of Radiologic Pathology Armed Forces Institute of Pathology Washington, DC & Assistant Professor of Radiology & Radiological Sciences Uniformed Services University of the Health Sciences Bethesda, MD

Classic AVM Arteriovenous shunting & no intervening capillary bed Enlarged feeding artery Nidus Early draining vein/ varix


Congenital Usually neural tissue in between

Occur anywhere in brain or spinal cord 98% solitary Multiple AVMS usually syndromic: Hereditary hemorrhagic telangiectasia (HHT) Cerebrofacial arteriovenous metameric syndromes (CAMS)

Nidus = Conglomeration of numerous AV shunts & dysplastic vessels

Hereditary Hemorrhagic Telangiectasia>3 concurrent cerebral AVMS Rare!

AVM Dysregulated angiogenesis continued vascular remodeling Peak age: 20-40 year old Risk of hemorrhage: 24%/year ~50% present with symptoms of hemorrhage NECT

An angiodyplastic disorder with AD inheritance

AVM Grading: Spetzler -Martin Scale Size Small (6 cm) = 3 Location Noneloquent = 0 Eloquent = 1 Venous drainage Superficial = 0 Deep = 1

AVM Imaging: CT Variable Hemorrhage Calcification: 25-30% Enhance postcontrast CTA: Enlarged arteries & draining veinsCECT


AVM Imaging: MRI Flow Voids: Bag of worms Variable hemorrhage Blooming on T2* GREFLAIR T2



T2: Increased signal gliosis Contrast: Strong enhancement MRA/MRV


AVM Imaging: Conventional Angiography Best method of imaging Must image ICA, ECA & vertebral circulations 27-32% of AVMs have dual arterial supply

Cerebrofacial Arteriovenous Metameric Syndromes

Orbit & Sinus: What are you looking for?

ObjectivesRecognize imaging findings in orbits & paranasal sinuses that will change patient management. Be able to develop checklist for imaging findings within orbits & paranasal sinuses that decreases likelihood of overlooking pertinent associated findings.

Alice Boyd Smith, Lt. Col., USAF MC Chief, Neuroradiology Department of Radiologic Pathology Armed Forces Institute of Pathology Washington, DC & Assistant Professor of Radiology & Radiological Sciences Uniformed Services University of the Health Sciences Bethesda, MD

Orbits & Sinuses Infection Trauma Neoplasm

Orbit: Infectious Pre - or post-septal Most often secondary to underlying paranasal sinusitis Maxillary & ethmoid most common

Other etiologies: Trauma Bacteremia Skin infections Dental infections CECT


Orbit: Infectious Subperiosteal abscess Spread from sinus to orbit Transmission via valveless venous plexus

Subperiosteal Abscess: Orbit CT:CECT Medial orbital wall with adjacent sinusitis Lentiform, rim enhancing Medial rectus displacement Lamina papyracea dehiscenceCECT

Direct extension: Lamina papyracea dehiscence

MR Post contrast: Rim enhancement; intra- & periorbital enhancement Fat suppression optimal

Visual disturbance:15-30% Optic neuritis Ischemia: intraorbital pressure Retinal ischemia: Central artery occlusion or thrombophlebitis

Requires immediate attention! May result in blindness

AVM: Associated Abnormalities Flow-related aneurysm on feeding artery: 10-15% Intranidal aneurysm: >50% Vascular steal: Ischemia in adjacent brain

Increased Risk of Hemorrhage Location Periventricular Basal ganglia Thalamus NECT

Arterial Pedicle aneurysm Intranidal aneurysm Difficult to detect by MR


Venous Central venous drainage Obstruction of venous outflow Varix

Small nidus

AVM: Treatment Embolization Radiation: Stereotaxic radiosurgery Eloquent

Arteriovenous Fistulas Distinguished from AVMs by presence of direct, high flow fistula between artery & vein Dural AVF (dAVF) Cavernous carotid fistula (CCF) Vein of Galen malformation



dAVF Arteriovenous shunts within dura 10-15% of intracranial vascular malformations 2 types: Adult: Tiny vessels in wall of thrombosed dural venous sinus typically middle aged & older patients Usually acquired - trauma T1 SSFSE SSFSE


Infantile: Multiple high-flow AVshunts involving several thrombosed dural sinuses

Fetal MRI

dAVF Grading: Cognard Classification Type I: In sinus wall, normal antegrade venous drainage Type II: In main sinus A: Reflux into sinus B: Reflux into cortical veins: 10-20% hemorrhage

dAVF Grading: Lalwani et al

Type III: Direct cortical drainage 40% hemorrhage

Type IV: Direct cortical drainage + venous ectasia 2/3 hemorrhage

Type V: Spinal perimedullary venous drainage Progressive myelopathy

Type I

Type II

Type III

Type IV

dAVF Most common near skull base Transverse sinus most common

dAVF Imaging: CT NECT: May be normal CECT: May see tortuous dural feeders & enlarged dural sinusCECT

Hemorrhage incidence: 2-4% per year Spontaneous closure rare Most are type I

dAVF Imaging: MRI Flow voids around dural venous sinus Thrombosed sinus Dilated cortical veins without parenchymal nidus T2: Focal hyperintensity in adjacent brain MRA: May be negative MRV: Occluded sinus, collateral flowT1+Gd T2 T2



dAVF: Conventional Angiography Multiple arterial feeders Dural/transosseous branches from ECA: most common Tentorial/dural branches from ICA or VA CECT


Involved dural sinus frequently thrombosed Flow reversal in dural sinus/cortical veins progressive symptoms, risk of hemorrhage Tortuous engorged pial veins pseudophlebitic pattern

Pseudophlebitic pattern

Carotid Cavernous Fistula (CCF) dAVF second most common site Abnormal communication between internal carotid artery & cavernous sinus Enlarges cavernous sinus Usually see enlarged superior ophthalmic vein CCF may be contralateral to dilated SOV

Venous DrainageSOVSuperficial Middle Cerebral V.

Uncal v. CerebellarCa Sin verno us us

Classified by arterial supply & venous drainage (Barrow): A: Direct ICA-cavernous sinus high-flow shunt B: Dural ICA branches-cavernous shunt C: Dural ECA-cavernous shunt D: ECA/ICA dural branches shunt to cavernous sinus


Pterygoid & basilar plexus

CCF: ImagingT1


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

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



dAVF: Treatment Endovascular Surgical resection Stereotaxic radiosurgery Observation: Indirect CCF

Vein of Galen Malformation (VOGM) Arteriovenous fistula involving aneurysmal dilatation of median prosencephalic vein (MPV) Neonatal > infant presentation Rare adult presentation

VOGM Newborns: Most common extracardiac cause of high-output congestive heart failure < 1% of cerebral vascular malformationsCECT

Drains MPV in 50%

Classification: Choroidal: Multiple feeders from pericallosal, choroidal, & thalmoperforating arteries Mural: Few feeders from collicular or posterior choroidal arteries


Falcine Sinus

Venous Pouch

VOGM: CT Findings Venous pouch May have hydrocephalus Parenchymal atrophy Intraventricular hemorrhage: Rare Post contrast: Avid enhancement of feeding arteries and veinCECT NCCT


VOGM: MR ImagingT2

VOGM: Angiography Choroidal or mural Dural venous sinus anomalies

Flow voids T1 hyperintensity In pouch thrombus In brain ischemia, calcification


Falcine sinus in 50% +/- absence or stenosis of other sinuses

DWI: Restricted diffusion if acute infarction

Choroidal VOGM

VOGM: Treatment Choroidal Medical therapy for congestive heart failure until 5 or 6 mo 5-6 mo: Transcatheter embolization

Mural Transcatheter embolization performed later


Cavernous Malformation AKA: Angioma, cavernoma, cavernous hemangioma Variable size intercapillary vascular spaces, sinusoids, & larger cavernous spaces No intervening brain 2 types: Inherited: Multiple & bilateral Sporadic

Cavernous Malformation: Imaging Little or no mass effect Unless complicated by hemorrhageT2

Cavernous MalformationT2

May have internal areas of thrombosis or hemorrhage Peripheral hemosiderin causes T2 shortening resulting in a black halo around the lesion

Cavernous MalformationNECT

Cavernous MalformationMRI NECT-Variable -Popcorn ball - Surrounding edema in acute hemorrhage -Post contrast: minimal/ no enhance look for DVA!T2 T1

CT Findings T1+Gd -Negative : 30-50% -40-60% Ca++ -No mass effect -Surrounding brain normal -Little or no enhance -CTA usually negative

Angiography: Usually occult

Cavernous Malformation Risk of hemorrhage: 0.250.7%/year More common in posterior fossa lesions In patients with prior hemorrhage annual rate of rehemorrhage 4.5% T2

Cavernous MalformationT2

Treatment: Observation: Asymptomatic or inaccessible lesions Surgical excision Radiosurgery: Progressively symptomatic but surgically inaccessible


Developmental Venous Anomaly (DVA) May represent anatomic variant Seen in up to 3% of autopsies

Developmental Venous Anomaly Isolated or associated with cavernous angioma Hemorrhage unusualT1+Gd

Enlarged medullary veins Drain into dural sinus or deep ependymal vein Usually solitary Medusa head or palm tree

DVA Imaging: CT Calcification & ischemia may occur in the region drained most likely due to chronic venous obstructive disease Rare NECT CECT CECT

DVA Imaging: MRI Surrounding T2 hyperintensity May occur in asymptomatic Acute edema from thrombosis Gliosis from chronic outflow obstruction


DVA: Treatment NONE! Removal may cause venous infarctionT1+Gd

Capillary Telangiectasia Dilated capillaries interspersed within normal brain Usually small, asymptomatic incidental findings Rare reports of hemorrhage exist

Capillary Telangiectasia T2: Increased signal T2*: Low signal Ill defined enhancement after contrast administration: Stippled/brush stroke Occult on angiography Treatment: None T1 T1+Gd T2

Most located in brainstem Pons

Capillary TelangiectasiaT1+Gd

Sinus Pericranii Communication between extracranial venous system & dural venous sinus Rare May be congenital or acquiredE

Sinus PericraniiCECT

Sinus PericraniiMRV T1+Gd

CT: Single/multiple bone defects Vascular enhancement Conventional angiogram: Seen during venous phase

Sinus Pericranii Spontaneous regression rare Risk of hemorrhage Treatment Surgery EndovascularT1+Gd

Vascular Malformations Arteriovenous malformation (AVM) Classic Dural arteriovenous fistula (dAVF) Vein of Galen Malformation (VOG)


Developmental venous anomaly (DVA) Cavernous malformation Capillary telangiectasia Cavernous Malformations

The EndThank you!