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AVM - Smith (RSNA 2010)
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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
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
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
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
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
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
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
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
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
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
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
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!