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Vascular Malformations: Brain 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 Vascular Malformations Arteriovenous malformation (AVM) – Classic Dural arteriovenous fistula (dAVF) Vein of Galen Malformation (VOG) Developmental venous anomaly (DVA) Cavernous malformation Capillary telangiectasia Shunt No Shunt Mixed Malformation = Combo 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) AVM Nidus = Conglomeration of numerous AV shunts & dysplastic vessels T2 Hereditary Hemorrhagic Telangiectasia An angiodyplastic disorder with AD inheritance >3 concurrent cerebral AVMS –Rare! AVM • Dysregulated angiogenesis Æ continued vascular remodeling Peak age: 20-40 year old Risk of hemorrhage: 2- 4%/year ~50% present with symptoms of hemorrhage NECT

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AVM - Smith (RSNA 2010)

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Page 1: AVM - Smith (RSNA 2010)

Vascular Malformations: Brain

Alice Boyd Smith, MDChief, Neuroradiology

Department of Radiologic PathologyArmed Forces Institute of Pathology

Washington, DC &

Assistant Professor of Radiology & Radiological SciencesUniformed Services University of the Health Sciences

Bethesda, MD

Vascular Malformations

• Arteriovenous malformation (AVM)– Classic– Dural arteriovenous fistula (dAVF)– Vein of Galen Malformation (VOG)

• Developmental venous anomaly (DVA)

• Cavernous malformation• Capillary telangiectasia

Shunt

No Shunt

Mixed Malformation = Combo

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)

AVM

Nidus = Conglomeration of numerous AV shunts & dysplastic vessels

T2

Hereditary Hemorrhagic Telangiectasia

An angiodyplastic disorder with AD inheritance

>3 concurrent cerebral AVMS –Rare!

AVM• Dysregulated

angiogenesisÆcontinued vascular remodeling

• Peak age: 20-40 year old

• Risk of hemorrhage: 2-4%/year– ~50% present with

symptoms of hemorrhage

NECT

Page 2: AVM - Smith (RSNA 2010)

AVM Grading: Spetzler -Martin Scale

• Size– Small (<3cm) = 1– Medium (3-6 cm) = 2– Large (>6 cm) = 3

• Location– Noneloquent = 0– Eloquent = 1

• Venous drainage– Superficial = 0– Deep = 1

AVM Imaging: CT

• Variable Hemorrhage

• Calcification: 25-30%• Enhance post-

contrast• CTA: Enlarged

arteries & draining veins

CECT

AVM

Calcification Hemorrhage

NECT NECT

AVM Imaging: MRI

• Flow Voids: “Bag of worms”

• Variable hemorrhage– “Blooming” on T2* GRE

• T2: Increased signal Ægliosis

• Contrast: Strong enhancement

• MRA/MRV

T2FLAIR

AVM

Cerebrofacial Arteriovenous Metameric Syndromes

AVM Imaging: Conventional Angiography

• Best method of imaging

• Must image ICA, ECA & vertebral circulations– 27-32% of AVMs have

dual arterial supply

Page 3: AVM - Smith (RSNA 2010)

Orbit & Sinus: What are you looking for?

Alice Boyd Smith, Lt. Col., USAF MCChief, Neuroradiology

Department of Radiologic PathologyArmed Forces Institute of Pathology

Washington, DC &

Assistant Professor of Radiology & Radiological SciencesUniformed Services University of the Health Sciences

Bethesda, MD

Objectives

• Recognize 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.

Orbits & Sinuses

• Infection• Trauma• Neoplasm

Orbit: Infectious

• Pre - or post-septal• Most often secondary to

underlying paranasalsinusitis– Maxillary & ethmoid most

common• Other etiologies:

– Trauma– Bacteremia– Skin infections– Dental infections

CECT

Panophthalmitis

Orbit: Infectious• Subperiosteal abscess

– Spread from sinus to orbit• Transmission via valveless

venous plexus– Direct extension:

• Lamina papyraceadehiscence

– Visual disturbance:15-30%• Optic neuritis • Ischemia:

– Ĺ intraorbital pressure– Retinal ischemia:

Central artery occlusion or thrombophlebitis

CECT

Subperiosteal Abscess: Orbit• CT:

– Medial orbital wall with adjacent sinusitis

• Lentiform, rim enhancing• Medial rectus displacement

– Lamina papyracea dehiscence• MR

– Post contrast: Rim enhancement; intra- & periorbital enhancement

• Fat suppression optimal• Requires immediate

attention!– May result in blindness

CECT

Page 4: AVM - Smith (RSNA 2010)

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

• Arterial– Pedicle aneurysm– Intranidal aneurysm

• Difficult to detect by MR• Venous

– Central venous drainage– Obstruction of venous outflow– Varix

• Small nidus

NECT

NECT

AVM: Treatment

• Embolization• Radiation: Stereotaxic

radiosurgery – Eloquent

• Surgery

Combination

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 Æ typically middle aged & older patients

• Usually acquired - trauma– Infantile: Multiple high-flow AV-

shunts involving several thrombosed dural sinuses Fetal MRI

SSFSE

dAVF

SSFSE T1

T1

Page 5: AVM - Smith (RSNA 2010)

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

• 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

dAVF Grading: Lalwani et al

Type I Type II Type III Type IV

dAVF

• Most common near skull base– Transverse sinus most

common• Hemorrhage incidence:

2-4% per year• Spontaneous closure

rare– Most are type I

dAVF Imaging: CT

• NECT: May be normal• CECT: May see tortuous dural feeders &

enlarged dural sinusCECT

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 flow

!!!

T1+Gd

dAVFT2 T2 T1 T1

Page 6: AVM - Smith (RSNA 2010)

dAVF: Conventional Angiography

• Multiple arterial feeders– Dural/transosseous branches from ECA: most

common– Tentorial/dural branches from ICA or VA

• Involved dural sinus frequently thrombosed• Flow reversal in dural sinus/cortical veins Æprogressive symptoms, risk of hemorrhage

• Tortuous engorged pial veins Æ”pseudophlebitic pattern”

dAVF

”Pseudophlebitic pattern””Pseudophlebitic pattern”

CECT

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

• 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

Venous Drainage

SOV

Pterygoid & basilar plexus

IPS

SPS

Superficial Middle Cerebral V.

Uncal v. Cerebellar

Cavernous Sinus

CCF: Imaging

• CT:– Marked dilation &

enhancement of cavernous sinus

– May see prominent SOV • MRI:

– Abnormal flow voids in cavernous sinus

– Enlargement of cavernous sinus

Non-Contrast

CCFT1

Page 7: AVM - Smith (RSNA 2010)

CCF

T1+Gd T2

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

• Classification:– Choroidal: Multiple feeders from

pericallosal, choroidal, & thalmoperforating arteries

– Mural: Few feeders from collicular or posterior choroidal arteries Falcine Sinus

Drains MPV in 50%

T1

VOGM• Newborns: Most common extracardiac cause of

high-output congestive heart failure• < 1% of cerebral vascular malformations

Venous Pouch

CECT

VOGM: CT Findings

• Venous pouch• May have

hydrocephalus• Parenchymal atrophy• Intraventricular

hemorrhage: Rare• Post contrast: Avid

enhancement of feeding arteries and vein

NCCTCECT

VOGM

Page 8: AVM - Smith (RSNA 2010)

VOGM: MR Imaging

• Flow voids• T1 hyperintensity

– In pouch Æthrombus

– In brain Æ ischemia, calcification

• DWI: Restricted diffusion if acute infarction

T2

T1

VOGM: Angiography

• Choroidal or mural• Dural venous sinus anomalies

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

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

VOGM

CECT

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

Page 9: AVM - Smith (RSNA 2010)

Cavernous Malformation: Imaging

• Little or no mass effect– Unless complicated by

hemorrhage• May have internal areas

of thrombosis or hemorrhage– Peripheral hemosiderin

causes T2 shortening resulting in a black “halo” around the lesion

T2

Cavernous Malformation

T2

Cavernous Malformation

NECT T1+GdCT Findings

-Negative : 30-50%

-40-60% Ca++

-No mass effect

-Surrounding brain normal

-Little or no enhance

-CTA usually negative

Cavernous MalformationNECTMRI

-Variable

-”Popcorn ball”

- Surrounding edema in acute hemorrhage

-Post contrast: minimal/ no enhance Æ look for DVA!

Angiography: Usually occult

T1T2

Cavernous Malformation• Risk of hemorrhage: 0.25-

0.7%/year– More common in posterior

fossa lesions– In patients with prior

hemorrhage annual rate of rehemorrhage Æ 4.5%

• Treatment:– Observation: Asymptomatic

or inaccessible lesions– Surgical excision– Radiosurgery:

Progressively symptomatic but surgically inaccessible

T2

Cavernous Malformation

MPGR

T2

Page 10: AVM - Smith (RSNA 2010)

Developmental Venous Anomaly (DVA)

• May represent anatomic variant– Seen in up to 3% of

autopsies• Enlarged medullary

veins• Drain into dural sinus or

deep ependymal vein• Usually solitary• “Medusa head” or “palm

tree”

Developmental Venous Anomaly• Isolated or associated with cavernous

angioma• Hemorrhage unusualT1+Gd

DVA Imaging: CT

• Calcification & ischemia may occur in the region drained Æ 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

T1+Gd

DVA: Treatment

• NONE!– Removal may cause

venous infarction

T1+Gd

Page 11: AVM - Smith (RSNA 2010)

Capillary Telangiectasia

• Dilated capillaries interspersed within normal brain

• Usually small, asymptomatic incidental findings– Rare reports of

hemorrhage exist• Most located in

brainstem Æ Pons

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

Capillary Telangiectasia

T1+Gd

E

Sinus Pericranii

• Communication between extracranial venous system & dural venous sinus

• Rare• May be congenital or

acquired

Sinus Pericranii

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

CECT

Sinus Pericranii

T1+GdMRV

Page 12: AVM - Smith (RSNA 2010)

Sinus Pericranii

• Spontaneous regression rare

• Risk of hemorrhage• Treatment

– Surgery– Endovascular

T1+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

T1+Gd

The End

Thank you!