Vascular Malformations Of CNS Radiology

VASCULAR MALFORMATIONS OF CNS

Dr Roshan ValentinePG Resident-RadiologySt Johns Medical CollegeBangalore

INTRODUCTION

• Heterogenous group of disorders• Morphogenetic errors affecting arteries , veins or

various combinations of vessels

CLASSIFICATION

HISTOPATHOLOGY

AVM Venous angioma Capillary telangiectasia

Cavernous malformation

CLASSIFICATION

FUNCTIONAL

AV SHUNTING

AVM

Dural Av fistula

VOG malformation

WITHOUT AV SHUNTING

Venous angioma

Capillary telangiectasi

a

Cavernous malformation

Sinus pericranii

AV MALFORMATION

• MC• Usually congenital• Tightly packed thin walled

vessels (NIDUS)• Direct artery to vein shunting• No intervening capillary bed• Most AVMs are parenchymal

lesions – aka PIAL AVMs

AV MALFORMATION

PATHOLOGY• LOCATION: supratentorial(85%)• SIZE : 2-6cms in diameter• NUMBER : solitary (<2%multiple)• Multiple when a/w syndromes HHT , Wyburn-Mason

syndrome

AV MALFORMATION

PATHOLOGYGROSS : Wedge shaped tangled irregulary dilated vessels with varying wall thickness and luminal size

Surrounding brain parenchyma : H’age residue , gliosis,ischemic changes

HPE: well defined elastic lamina(usually absent in venous channels ) with focal areas of wall thinning

AV MALFORMATION

CLINICAL FEATURES• Presentation: 2-4th decade• Headache with H’age – MC • Seizures > hemorrhage(adults )• Seizures < hemorrhage(children )

Nidus – MC site for hemorrhage Location – peri/interventricular /basal ganglia

• Focal neurological deficits(20-25%) STEAL from adjacent normal area Mass effect

AV MALFORMATION

AV MALFORMATION

PROGNOSIS• All are potentially hazardous• Lifelong risk of H’age- 2-4% every year cumulative• Spontaneous regression – rare and unpredictable

AV MALFORMATION

IMAGINGGENERAL FEATURE• 3 components– Feeding arteries– Central Nidus– Draining veins

AV MALFORMATION

IMAGINGCT• NECT

– Normal : Very small AVM– Iso/hyperdense serpentine vessels(BAG

OF WORMS)– Calcification(25-30%)– AVM Bleed – parenchymal , IVH >> SAH– Post embolization: hyperdense embolics

in nidus CECT• Enhanced arterial feeders , nidus and

draining veins

AV MALFORMATION

MR• T1W1 – tightly packed mass or honeycomb of flow

voids• T2W1 – serpiginous honeycomb of flow voids adjacent high signal tissue – gliosis• FLAIR- flow voids +/- surrounding high signal• GRE - blooming (H’agic residua)

AV MALFORMATION

ANGIOGRAPHY• Internal angioarchitecture best depiction• Depicts 3 components of AVM– Enlarged arteries+/- aneurysm– Nidus– Early draining veins

AV MALFORMATION

ANGIOGRAPHYFeeding arteries • Dilated and tortuous • Flow related angiopathy – dilatation , stenosis or

thrombosis• Pedicle aneurysm(10-15%cases)

AV MALFORMATION

ANGIOGRAPHYNidus• Tightly packed tangle of abnormal arteries and veins

with no intervening capillary bed/brain parenchym

• Intranidal aneurysm(50% cases)

AV MALFORMATION

ANGIOGRAPHYDraining Veins• Opacify in mid-late arterial phase(Early draining

vein) • Enlarged , tortuous and may form varices exerting

local mass effect• Stenosis can cause AVM H’age by ↑ intranidal

pressure

AV MALFORMATION

TREATMENT• Complete obliteration of nidus for cure• Traditonal Rx – Surgical excision for nidus• Acute and emergent surgical intervention – in life

threatening ICH

AV MALFORMATION

STEREOTACTIC RADIOSURGERY• Focussed irradiation to nidus• Indication – Unresectable because of location– Size < 3.5cms

• Adv : Non invasive• Disadv :Effect takes yearsRisk of h’age till it disappears completely

AV MALFORMATION

ENDOVASCULAR RX• Adjunct to Sx/ RadioSx• Used in small AVMs or 1-2 feeding arteries• Embolisation – Precedes surgery /radiosx

reduce size of nidus• Complete cure if : small AVM , few feeders , single

draining vein

DURAL AV FISTULA

• 2nd MC CVM with AV shunting• Tiny crack like vessels that

shunt blood b/w meningeal arteries and small venules within dural sinus wall

• ETIOLOGY : Acquired – ↑ angiogenesis within

dural sinus wall after thrombosis

DURAL AV FISTULA

PATHOLOGY• LOCATION: Trans Sinus>Sig sinus>Cav sinus(adults) Sup Sigmoid sinus (Children)• SIZE : Tiny single vessel shunts to massive complex

lesions with multiple feeders• NUMBER : Multiple lesions are uncommon

DURAL AV FISTULA

PATHOLOGYGROSS : Multiple enlarged dural feeders on the wall of thrombosed dural sinus : Fistulas connecting feeders with arterialized draining veins

HPE: irregular intimal thickening with variable loss of internal elastic lamina

DURAL AV FISTULA

CLINICAL FEATURE• Mostly in adults(40-60yrs)• C/F varies wht location and drainage pattern

TS-SigS - Bruit and tinnitus Cav S – Pulsatile proptosis , chemsois , retroorbital

pain• Lesions with cortical venous drainage(Malignant

dAVF) : seizures, dementia , progressive FND

DURAL AV FISTULA

CLINICAL FEATUREPROGNOSIS• 98% w/o cortical venous drainage - benign course• Malignant dAVF – aggressive clinical course with

H’age and ND• Multiple dAVF – poor clinical prognosis

DURAL AV FISTULA

TREATMENT• Conservative – Observation +/- carotid compression

techniqueIf rsk of H’age• Endovascular – Embolisation of arterial feeders with

particulate or liquid agents , coil embolization of venous sinus

• Surgical resection of involved dural venous sinus• Stereotactic RadioSx- 2-3 years for obliteration

DURAL AV FISTULA-IMAGING

GENERAL FEATURES• Mostly in posterior fossa and skull base• MC – TS-SigS junction


CT• Normal to striking• Enlarged dural sinus or draining vein/transosseous

venous channels• Car-Cav fistula : Enlarged SOV • CECT – Enlarged feeding arteries and draining veins Dural sinus may be thrombosed or stenotic


MRI• Dilated cortical vein without nidus adjacent to

normal appearing brain • MC finding – thrombosed dural venous sinus with

flow voids• Thrombus – T1 and T2 isointense typically T2* - blooming


ANGIOGRAPHY• Best imaging tool• DSA with superselective catheterization of dural and

transosseous feeders required• Dural branches – arise from ECA , ICA and vertebral

arteries• Presence of dural sinus thrombosis, flow reversal with

drainage into cortical veins and engorged tortuous pial veins


ANGIOGRAPHY• High flow venopathy can cause stenosis . Occlusion

or hemorrhage• Dysplastic venous pouches may cause H’age• Increased H’age with cortical venous drainage and

dysplastic venous dilatation

DURAL AV FISTULA

CAROTID CAVERNOUS FISTULA

• AV shunting developing within cavernous sinus

• Direct– High Flow– Rupture of cavernous ICA

into CS• Indirect– Slow flow , low pressure– Fistula b/w dural br of ICA

and the CS


ETIOLOGY• Almost always acquired• Direct– Traumatic: central skull base #– Non-Traumatic: Preexisting cavernous ICA

aneurysm• Indirect– Degenerative – sequelae of dural sinus thrombosis


PATHOLOGY• GROSS – Dilated CS (Direct CCF)– Enlarged crack like vessels(Indirect)


CLINICAL FEATURES

DIRECT INDIRECTEPIDEMIOLOGY Less common More common

DEMOGRAPHICS M=FAny age

Women40-60yrs

PRESENTATION BruitPulsatile xophthalmosOrbital edema↓visionGlaucoma

Painless proptosis Vision changes

TREATMENT Fistula closure by transarterial transfistula detachable balloon embolisation

Conservative

Superselectiv eembolisation

CAROTID CAVERNOUS FISTULA-IMAGING

GENERAL FEATURES• Presence of AV shunting within cavernous sinus• Based on degree of shunt – subtle to striking


CT FINDINGS• Mild or striking proptosis• Prominent CS• Enlarged SOV • Enlarged EOMCECT• Enalrged SOV and CS


MRI• T1 – Bulging SOV

and CS with flow voids

• T2 – Asymmetric flow related signal loss in the affected veins


ANGIOGRAPHYDIRECT CCF• Rapid flow with early opacification of CS• Fistula may be noted in ICA segmentINDIRECT CCF• Multiple dural feeders from Cavernous br of ICA and

deep br of ECA(mid meningeal and dist max A)• Anastomoses b/w ICA and ECA feeders are common

VEIN OF GALEN ANEURYSMAL MALFORMATION

• Direct AV fistula b/w deep choroidal arteries and persistent embryonic precursor of VOG

• Large midline venous pouch behind the 3rd ventricle

• MC extracardiac cause of high-output cardiac failure in newborn


• In normal fetal dvpt : arterial supply of choroid plexus drains via single transient midline vein – median prosencephalic vein

• Internal cerebral vein drains fetal chorid plexus as MPV regresses

• Persistent high flow fistula prevents regression


CLINICAL FEATURES• >30% of symptomatic VM in children• Rare in adults• Neonates – high output CCF with cranial bruit• Older infants – macrocrania + hydrocephalus +/- CCF• Older Children – Developmental delay and seizures• Young adults - Headache• Large VGAMS – cerebral ischemia and dystrophic changes• Left untreated – Die of progressive brain damage andintracatable CCF


TREATMENT • Goal – not anatomic cure of VGAM but control

malformation to allow normal brain dvpt• Staged arterial embolization at 4/5m

VGAM – IMAGING

CT• NECT

– Enlarge dwell delineated hyperdense mass at tentorial apex

– Obstructive hydrocephalus– H’age and calcification

may be present.• CECT – Strong uniform

enhancement

VGAM – IMAGING

MRI• Enlarged serpentine

arterial feeders adjacent to the lesion

VGAM – IMAGING

ANGIOGRAPHY2 forms based on angioarchitecture• Choroidal – Multiple br from pericallosal choroidal and

thalamoperforate arteries drain into dilated midline venous sac

• Mural – single or few enlarged collicular or post choridal arteries drain into sinus wall

• Venous drainage into persistent embryonic FALCINE SINUS

VGAM – IMAGING

VGAM – IMAGING

ULTRASOUND• Antenatally• Hypoechoic to

mildle echogenic midline mass behinf the third ventricle

• CDFI : Bidirectional turbulent flow

CVMS WITHOUT AV SHUNTING

DEVELOPMENTAL VENOUS ANOMALY

• VENOUS ANGIOMA/VENOUS MALFORMATION

• Umbrella shaped CVM with mature venous part.

• No arterial component• May represent anatomic

variant of otherwise normal venous drainage


CLINICAL FEATURES• Usually asymptomatic• Headache/seizures• H’age with FND ( if a/w cavernous malformation)• MC vascular malformation at autopsy


TREATMENT• Solitary DVA – no Rx• Histologically mixed – based on coexisting lesion


IMAGING• Location : MC near the frontal horn of ventricle• Size < 3cm• Usually solitary


NECT• Normal , enlarged draining vein may appear

hyperdenseCECT• Numerous linear or punctate enhancing foci and

converge on single enlarged tubular draining vein


MR• T1 – Normal if DVA is small H’age if mixed malformations• T1 C+ - stellate collection of linear enhancement

structures joining subependymal collector vein.• GRE – if H;age in coexisting cavernous malformation - Occasionally hypo – Not H’age but deoxyHb within venous blood


• MRA – Arterial phase usually normal• MRV – MEDUSA HEAD drainage pattern


ANGIOGRAPHIC FINDINGS• Normal arterial and

capillary phase• Venous phase –

Medusa head appearance

CAVERNOUS MALFORMATION

• CAVERNOUS ANGIOMA/CAVERNOMA

• Characterised by intralesional hemorrhages into thin walled angiogenically immature blood filled locules called CAVERNS

• Well marginated lesion with no normal brain parrenchyma

• Inherited or acquired


PATHOLOGY• Location : Mostly infratentorial (PONS) • Dark blue well circumscribed lobulated lesion with mulberry like

config• CCMs do not contain brain parenchyma• Adjacent parenchyma: reactive changes , hemosiderin deposition• Dystrophic calcification+• HPE – collagenised sinusoids with NO

MUSCULARIS/ELASTICA(avm has it )


CLINICAL FEATURES • 2/3 are soliary • Peak presentn : 40-60yrs• MC presentn : Seizures(50%)>Headache and FND• H’age risk – 0.25-0.75% per year


TREATMENT OPTIONS• Total surgical removal via microsurgical resexn – for

symptomatic lesions with recurrent H’age• Stereotactic Radiosx = for inaccessible lesions


IMAGINGCT – Hyperdense lesion with scatteres intralesional calcification

CAVERNOUS MALFORMATION-IMAGING

MRIMR – DIAGNOSTIC

Focal central heterogeneity(varying hemorrhage within caverns)- POPCORN appearance on T2WI Circumferential hypointense ring of hemosiderin form around high intense central areas

CAVERNOUS MALFORMATION-IMAGING

ANGIOGRAPHY• No identifiable feeding arteries/veins• Negative unless mixed with other lesions

CAPILLARY TELANGIECTASIA

• CAPILLARY ANGIOMA• Collection of enlarged thin

walled vessels resembling capillaries.

• Vessels surrounded by normal brain parenchyma

• Probably congenital lesions• MC sites : Pons , cerebellum(can

occur anywhere)


CLINICAL FEATURES• Peak Presentation : 30-40 years• Usually silent, discovered incicdentally at imaging


IMAGING• Usually <1cmCT – Usually NormalMR• T1W1 –usually normal• T2 – 50% normal - 50 % show stippled foci of hyperintensity• T2* - Best sequence for

demonstrating the lesion(poorly delineated greyish hypointensity)

• T1+C – BRUSH LIKE

SINUS PERICRANII

• Large transcalvarial communication between intra and extra-cranial venous drainage system

• Mostly congenital• May be a/w other

dva

SINUS PERICRANII

CLINICAL FEATURES• Rare• Children and young adults• NON TENDER NON PULSATILE BLUISH

COMORESSIBLE SCALP MASS• Increase in size with Valsalva• Reduce on upright position

SINUS PERICRANII

TREATMENT• Surgical removal of extracranial component-

cosmetic purpose

SINUS PERICRANII- IMAGING

CT NECT• Iso to hyperdense • Typically well demarcated

calvarial defectCECT• Strong uniform

enhancement

SINUS PERICRANII-IMAGING

MRI• T1WI – iso• T2WI- HyperintenseANGIOGRAM• Arterial and capillary phase

normal• Venous phase – Visualised on

late venous phase mostly• Contrast accumulating within

the lesion and adjacent to the skull defect with pericranial scalp vein

ENDOVASCULAR MANAGEMENT of CVM

EMBOLIC AGENTS USEDLiquid agents Acrylic glue• Chemically N-butyl

cyanoacrylate• Polymerises on contact

with hydroxyl ions in blood• Induces vasculitis and

thereby thrombosis of AVM


ONYX• Ethylene vinyl alcohol polymer• Mixed with dimethyl sulfoxide (DMSO)• On mixing it forms a soft spongy polymer• Its more effective than acrylic glue


PARTICULATE AGENTSSILICONE SPHERES• First agents ever used• Mixed with Ba to make it radiopaque• Increased rebleeding rate


BALLOONS• Silicone or latex made• Occlude large AVM feeding arteries/high flow fistula• Replaced by coilsPOLY VINYL ALCOHOL• Delivered via guide wire dependent catheters(~500mics)• Flow dependent catheters (<350mics)• Clumping of particles causing slowing and then thrombosis


MICROCOILS• Used along with

embolic agents• They reduce the flow

in rapid av shunts• Also in treatment of

intracranial aneurysm a/w AVMs

Vascular Malformations Of CNS Radiology

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