Vascular Malformations LTC Robert Shih Chief of Neuroradiology Walter Reed Medical Center Special thanks to LTC Alice Smith (retired)
Disclosures: None. This presentation reflects the personal views of the speaker and not of the US government or Department of Defense.
What imaging pattern is associated with higher risk of hemorrhage in a patient with dural arteriovenous fistula (davf)? 1. Pseudosubarachnoid sign 2. Pseudophlebitic pattern 3. Palm tree" appearance 4. Brush stroke" appearance
Regarding cavernous malformations, why might intravenous contrast be administered? 1. Evaluate the full extent of the lesion 2. Assess for presence of other cavernous malformations 3. Look for associated developmental venous anomaly 4. Assess arterial and venous supply T1+Gd Cavernous Malformations
Which imaging finding would be most characteristic of a capillary telangiectasia? 1. Mild to moderate mass effect 2. Faint stippled appearance on T1 post contrast 3. High signal on T1 weighted imaging 4. Presence of a hemosiderin rim
Objectives Describe the typical imaging appearance of the four intraaxial vascular malformations. Understand their clinical significance and the possible treatment options. List a few extraaxial vascular malformations.
Vascular Malformations Arteriovenous malformation (AVM) Classic AVM (intraaxial nidus) Pial arteriovenous fistula (pavf) Dural arteriovenous fistula (davf) Developmental venous anomaly (DVA) Cavernous malformation Capillary telangiectasia Shunt Mixed Malformation = Combo No Shunt
Teaching Point There are four intra-axial vascular malformations: AVM, cavernous malformation, developmental venous anomaly, and capillary telangiectasia.
Classic AVM 98% solitary Multiple AVMs usually syndromic: Hereditary hemorrhagic telangiectasia (HHT) Cerebrofacial arteriovenous metameric syndrome (CAMS)
Hereditary Hemorrhagic Telangiectasia An angiodysplastic disorder with AD inheritance May have multiple pial AVMs or AVFs
Intra/extracranial AVMs: CAMS Cerebrofacial Arteriovenous Metameric Syndrome
T2 AVM: Parenchymal Vascular Nidus
AVM: Clinical Significance Peak presentation age: 20-40 year old Risk of hemorrhage: 2-4%/year ~50% present with symptoms of hemorrhage Seizures, headaches, focal neurologic deficits NECT
AVM Grading: Spetzler-Martin 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 Intraaxial nidus of abnormal vessels Variable Hemorrhage Calcification: 25-30% Enhance post-contrast CTA: Enlarged feeding arteries and draining veins (AV shunting) CECT
AVM Imaging: CT NECT NECT Calcification Hemorrhage
AVM Imaging: MRI flow voids T2 FLAIR
AVM: Feeding Arteries & Draining Veins
AVM Imaging: Catheter Angiography Must image ICA, ECA, & vertebral circulation 27-32% of AVMs have dual arterial supply
AVM: Associated Abnormalities Flow-related aneurysm on feeding artery: 10-15% Intranidal aneurysm: >50% Vascular steal : Ischemia in adjacent brain
Increased Risk of Hemorrhage NECT Location (deep) Periventricular Basal ganglia Thalamus Arterial (aneurysm) Pedicle aneurysm Intranidal aneurysm Difficult to detect by MR Venous (stenosis or ectasia) Central venous drainage Obstruction of venous outflow Varix or venous pouch Small nidus! NECT
AVM: Treatment Surgery: Microvascular resection Radiation: Stereotactic radiosurgery Embolization: Liquid adhesive Observation: Risk of treatment vs disease
Teaching Point Classic or pial AVMs have an intraaxial (parenchymal or ventricular) nidus with enlarged feeding arteries and draining veins due to arteriovenous shunting.
Cavernous Malformation AKA: Cavernous angioma, cavernoma, cavernous hemangioma 2 types: Inherited: Multiple & bilateral Sporadic
Cavernous Malformation: Imaging T2
Cavernous Malformation: Imaging T2
Cavernous Malformation T2
Cavernous Malformation NECT T1+Gd
Cavernous Malformation NECT T2 T1
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 4.5% Treatment: Observation: Asymptomatic or inaccessible lesions Surgical excision Radiosurgery: Progressively symptomatic but surgically inaccessible T2
Cavernous Malformation T2 MPGR, GRE, SWI = T2* weighted sequences
Teaching Point Cavernous malformation is a no flow or angiographically occult lesion that may be associated with a developmental venous anomaly (prenatal venous obstruction).
Developmental Venous Anomaly (DVA)
Developmental Venous Anomaly Isolated or associated with cavernous malformation Hemorrhage unusual T1+Gd
DVA Imaging: CT Calcification & ischemia may occur in the region drained most likely due to chronic venous obstructive disease Rare for DVA to cause venous complications NECT CECT CECT
Images courtesy Jason Schroeder, MD DVA Imaging: MRI T2 SWI Surrounding T2 hyperintensity May occur in asymptomatic patients Acute edema from venous thrombosis Gliosis from chronic outflow obstruction T1+Gd
T1+Gd DVA
DVA: Treatment NONE! Removal may cause venous infarction T1+Gd
Teaching Point DVAs are benign incidental findings and are not to be confused with AVMs.
Capillary Telangiectasia
Capillary Telangiectasia T1 T2 T1+Gd
Brainstem Glioma
Capillary Telangiectasia T2 T1+C T2*
Capillary Telangiectasia T1+Gd E
Teaching Point Capillary telangiectasias are also benign incidental findings and are best seen on T2*-weighted or postgadolinium images.
Vascular Malformations Arteriovenous malformation (AVM) Classic AVM (intraaxial nidus) Pial arteriovenous fistula (pavf) Dural arteriovenous fistula (davf) Developmental venous anomaly (DVA) Cavernous malformation Capillary telangiectasia Shunt Mixed Malformation = Combo No Shunt
Arteriovenous Fistulas Distinguished from AVMs by presence of a direct high flow fistula between artery & vein Pial AVF (pavf) Dural AVF (davf) Cavernous carotid fistula (CCF) Vein of Galen malformation These are less common than intraaxial AVMs in the head (reverse is true in the spine).
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 Infantile: Multiple high-flow AVshunts involving several thrombosed dural sinuses SSFSE Fetal MRI
AVF SSFSE 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
CECT davf Imaging: CT
davf Imaging: MRI T2 T1+Gd!!! MRA: May be negative MRV: Occluded sinus, collateral flow
davf T2 T1 T1
davf: Conventional Angiography Multiple arterial feeders Dural/transosseous branches from ECA: most common Tentorial/dural branches from ICA or VA Dural sinus may be thrombosed Flow reversal in dural sinus/cortical veins risk of hemorrhage Tortuous engorged pial veins pseudophlebitic pattern
davf CECT Pseudophlebitic pattern
Teaching Point Dural AVFs are extra-axial lesions usually located in the wall of a venous sinus. Involvement of cortical veins is the major risk factor for hemorrhage.
Carotid Cavernous Fistula (CCF) The cavernous sinus is the second most common location for a dural AVF. This is also known as an indirect CCF. Fistula between arteries to the dural wall and the venous sinus. A hole in the cavernous internal carotid artery would cause a high flow AVF. This is also known as a direct CCF. Trauma or ruptured aneurysm.
Venous Drainage SOV Superficial Middle Cerebral V. Uncal v. Cerebellar SPS Pterygoid & basilar plexus IPS
CCF: CT Imaging Non-Contrast
T1 CCF: MRI
CCF: Venous arterialization T1+Gd T2
CCF: Arteriovenous Shunting SOV IMAX Indirect Courtesy Steven Goldstein, MD
CCF: Treatment Endovascular Surgical resection Observation: Indirect CCF (dural AVF) Cortical venous reflux is risk factor for future hemorrhage
Teaching Point Carotid-cavernous fistulas may be direct (hole in cavernous ICA) or indirect (davf in the dural wall of the cavernous sinus).
Vein of Galen Malformation (VOGM) Neonatal > infant presentation Rare adult presentation Classification: Choroidal: Multiple feeders from pericallosal, choroidal, & thalmoperforating arteries Mural: Few feeders from collicular or posterior choroidal arteries Drains MPV in 50% Falcine Sinus T1
VOGM is a type of AVF < 1% of cerebral vascular malformations CECT Venous Pouch
VOGM
VOG Malformation: Prenatal US
VOG SSFSE T2
VOGM: CT Findings CECT NCCT
VOGM: MR Imaging T2 T1
VOGM: Angiography Choroidal or mural Dural venous sinus anomalies Falcine sinus in 50% +/- absence or stenosis of other sinuses
VOGM: Angiography Choroidal
VOGM: Treatment Choroidal Medical therapy for congestive heart failure until 5 or 6 mo 5-6 mo: Transcatheter embolization Mural Transcatheter embolization performed later
CECT VOGM
Teaching Point Vein of Galen aneurysm is really a pial AVF (choroidal arteries to median prosencephalic vein).
Sinus Pericranii Communication between extracranial venous system & dural venous sinus Rare May be congenital or acquired
Sinus Pericranii CECT CT: Single/multiple bone defects Vascular enhancement Conventional angiogram: Seen during venous phase
T1+Gd MRV Sinus Pericranii
Sinus Pericranii Spontaneous regression rare Risk of hemorrhage Treatment Surgery Endovascular T1+Gd
Teaching Point Sinus pericranii is a scalp varix with an anomalous communication to the underlying dural venous sinus.
Vascular Malformations Intraaxial Arteriovenous malformation (AVM) Parenchymal or ventricular nidus Cavernous malformation Developmental venous anomaly (DVA) Capillary telangiectasia Extraaxial Arteriovenous fistula Pial on surface of brain (e.g. HHT or VOG) Dural in wall of venous sinus (e.g. transverse) Carotid-cavernous fistula Direct (hole in ICA) Indirect (dural AVF) Sinus pericranii
What imaging pattern is associated with higher risk of hemorrhage in a patient with dural arteriovenous fistula (davf)? 1. Pseudosubarachnoid sign 2. Pseudophlebitic pattern 3. Palm tree" appearance 4. Brush stroke" appearance
Regarding cavernous malformations, why might intravenous contrast be administered? 1. Evaluate the full extent of the lesion 2. Assess for presence of other cavernous malformations 3. Look for associated developmental venous anomaly 4. Assess arterial and venous supply T1+Gd Cavernous Malformations
Which imaging finding would be most characteristic of a capillary telangiectasia? 1. Mild to moderate mass effect 2. Faint stippled appearance on T1 post contrast 3. High signal on T1 weighted imaging 4. Presence of a hemosiderin rim
Objectives Describe the typical imaging appearance of the four intraaxial vascular malformations. Understand their clinical significance and the possible treatment options. List a few extraaxial vascular malformations.
The End Thank you!