avm - smith (rsna 2010)
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AVM - Smith (RSNA 2010)TRANSCRIPT
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
AVMT2
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
AVMNECT NECT
AVM Imaging: MRI Flow Voids: Bag of worms Variable hemorrhage Blooming on T2* GREFLAIR T2
Calcification
Hemorrhage
T2: Increased signal gliosis Contrast: Strong enhancement MRA/MRV
AVM
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
Panophthalmitis
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
NECT
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
Combination
Surgery
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
dAVFT1
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
dAVFT1 T1
!!!
dAVF: Conventional Angiography Multiple arterial feeders Dural/transosseous branches from ECA: most common Tentorial/dural branches from ICA or VA CECT
dAVF
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
SPS IPS
Pterygoid & basilar plexus
CCF: ImagingT1
CCF
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+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
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
T1
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
VOGM: MR ImagingT2
VOGM: Angiography Choroidal or mural Dural venous sinus anomalies
Flow voids T1 hyperintensity In pouch thrombus In brain ischemia, calcification
T1
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
VOGMCECT
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
MPGR
Developmental Venous Anomaly (DVA) May represent anato