Cerebral vascular malformations

1. Vascular
Malformations
Ariunjargal.B

2. Vascular Malformations
(i) Malformations with AV shunts :
a) AVM
b) Dural AVF
c) Pial AVF
(ii) Malformations without AV shunts :
a) Cavernous Malformation
b) Venous Malformations
c) Capillary Telangiectasia
d) Moyamoya Disease

3. (i) Malformations with AV shunts :
a) AVM
b) Dural AVF
c) Pial AVF

4. Incidence :
- Peak age is 20 to 40 years
- 98% of AVM are solitary,
- multiple (2%)associated with syndromes
- Multiple lesions in various syndromes, Osler-Weber-
Rendu and Wyburn-Mason
- Occurs intra-axially & 85 % are supratentorial
Clinical Picture :
-One or combination of hemorrhage (usually
parenchymal hemorrhage, rarely subarachnoid, 40
%), seizures (30 %), neurological deficit or headache
(20 %)

5. Types :
a) Parenchymal, 80% (ICA and vertebral artery
supply, congenital lesions)
b) Dural, 10% (ECA supply, mostly acquired
lesions)
c) Mixed, 10%

6. Cerebrofacial Arterio-venous Metameric Syndrome
(CAMS) :
-CAMS (also known as Wyburn-Mason syndrome or
Bonnet-Dechaume-Blanc disease)
CAMS type 1 :
-Involves the medial prosencephalon and will manifest
with AVMs located at the corpus callosum,
hypothalamus (hypophysis) and nose
CAMS type 2 :
-Involves the lateral prosencephalon with AVMs at the
occipital lobe and optic tract including the thalamus,
retina and maxilla

7. CAMS type 3 :
-Involves the rhombencephalon and affected patients
will have AVMs at the cerebellum, pons and
mandible
-The most important clue to the diagnosis of CAMS is
the presence of multiple AVMs in both the brain
parenchyma and the facial region

8. CAMS type 2 in a 10-year-old girl who presented with a 1-year history of progressive right
hemiparesis , chemosis and proptosis of the left eye were also noted (a, b) CT+C obtained at
the level of the orbits (a) and brain (b) show an enhancing vascular lesion at the left basal
ganglia , the lesion exerts a mass effect on the left lateral ventricle , in addition , serpiginous
structures are seen surrounding the optic nerve , (c) Lateral LT ICA angiogram shows a
proliferative type brain AVM nidus at the basal ganglia , another smaller AVM is noted
surrounding the left optic nerve (solid arrow) , there is early venous drainage anteriorly into
the basal frontal cortical veins (arrowheads) and posteriorly into the basal vein of Rosenthal
(open arrow)

9. CAMS type 2 in a 7-year-old girl who presented with recurrent episodes of
bleeding from the gum due to eruption of a left molar , (a) Coronal CT scan
(bone window) reveals an osteolytic lesion within the alveolar ridge of the
left maxilla , (b, c) Left external (b) and internal (c) carotid angiograms show
a facial osseous AVM supplied by branches of the internal maxillary and
transverse facial arteries and draining into an intraosseous venous pouch
(arrow in b) , this finding corresponds to the osteolytic lesion seen in a and
proved to be the source of the patient’s bleeding , an AVM of the left optic
nerve is also noted, thereby allowing the diagnosis of CAMS type 2

10. Proliferative Angiopathy :
-Cerebral proliferative angiopathy, previously known as
diffuse nidus type AVM, is present in an estimated
2%-4% of all brain AVMs
-There is a female predilection of 2:1 with a rather
young mean patient age (20 years)
CT & MRI :
-The typical MR imaging and CT findings include a
proliferative type nidus in which normal brain
parenchyma is interspersed between the abnormal
vessels
-Often an entire lobe or even brain hemisphere is
affected

11. (a) PD , (b) T1+C show multiple flow voids and contrast-enhanced tubular
structures representing a large vascular lesion that involves the entire
right cerebral hemisphere , the normal brain parenchyma is interspersed
between the abnormal vessels

12. Left occipital arteriovenous malformation (AVM) with multiple calcified phleboliths
and numerous hyperattenuating vascular channels

13. CT+C shows a tangle of intensely enhancing tubular structures embedded in
the left parietal lobe , a finding that is compatible with a nidus ,
hyperattenuation representing intraventricular hemorrhage is noted in the
ventricles

14. MRI :
-Serpiginous black flow voids
-May be evidence of local atrophy and gliosis (as a
result of vascular steal and ischemia) or previous
hemorrhage
-AVM replaces but does not displace brain tissue (i.e.
mass effect is uncommon) unless complicated by
hemorrhage and edema
-Edema occurs only if there is recent hemorrhage or
venous thrombosis with infarction
-There are usually adjacent changes to the adjacent
brain including gliosis (T2 prolongation), dystrophic
calcification & blood products (blooming T2*
gradient imaging), the gliosis / encephalomalacia or
mineralization seen in the adjacent brain is due to
alteration in vascular flow from the AVM

15. T1 shows large occipital arteriovenous malformation (AVM) with parasagittal flow
void

16. T2 showing numerous flow voids

17. Grading System : (Spetzler's Criteria)
0 1 2 3
Eloquence No Yes - -
Draining vein Superficial Deep - -
Size - >3cm 3-6cm <6cm

18. -Higher score is associated with higher chance of
hemorrhage
-Other factors associated with poorer prognosis/higher
risk of hemorrhage :
1-Intranidal aneurysm
2-Aneurysm in the circle of Willis
3-Aneurysm in arterial feeder
4-Venous stasis

19. -Eloquence of adjacent brain :
a) Eloquence brain :
-Sensorimotor, language, visual cortex,
hypothalamus, thalamus, brain stem,
cerebellar nuclei or regions directly adjacent
to these structures
b) Non-eloquence brain :
-Frontal and temporal lobe, cerebellar
hemispheres

20. Complications :
a) Hemorrhage (parenchymal > SAH >
intraventricular)
b) Seizures
c) Cumulative risk of hemorrhage is
approximately 3 % per year
Treatment Options :
a) Surgery
b) Endovascular embolization
c) Radiosurgery
d) Conservative management

21. b) Dural Arteriovenous Fistula (DAVF) :
1-Incidence :
-Dural AVFs are abnormal connections between arteries that
would normally feed the meninges bone or muscles but not the
brain and small venules within the dura mater
-Acquired lesions presenting in older population (50-70 years)
compared to AVM (20-40 years)
2-Etiology :
-Occur following damage to venous structures (post-thrombosis,
surgery & trauma)
-They typically have multiple feeders and are usually acquired,
most frequently from as a result of neovascularisation induced
by previously thrombosed dural venous sinus (typically
transverse sinus)

22. -Therefore supply is typically from the same
branches that supply meningeal arterial supply :
a) Supratentorial : Middle meningeal artery (ECA)
b) Anterior cranial fossa : Ethmoidal branches of
the ophthalmic artery (from ICA)
c) Cavernous sinus : Dural branches from the ICA
and accessory meningeal branch of the maxillary
artery (via foramen ovale), branch of ECA
d) Posterior cranial fossa :Dural branches from the
vertebral arteries, branches from occipital and
ascending pharyngeal arteries, branches of ECA

23. Clinical Picture :
-Symptoms & signs secondary to arterialization of venous
system :
a) Bruit
b) Venous hypertension
c) Pulsatile tinnitus (if primary involvement is sinuses)
d) Hemorrhage
e) Focal neurology
f) Seizures
g) Caroticocavernous fistula may give rise to proptosis &
chemosis

24. Location :
a) Transverse/ sigmoid sinus : Most common
b) Cavernous sinus
c) Superior sagittal sinus
d) Straight Sinus
e) Other venous sinuses
f) Anterior cranial fossa : Typically only ICA supply
due to meningeal supply of this region
g) Tentorium

25. CT & MRI :
-Often normal unless complications (e.g.
hemorrhage, enlargement of cavernous sinus and
superior ophthalmic veins if caroticocavernous
fistula)
-Dilated cortical veins (a condition referred to as a
pseudophlebitic) which manifest as abnormal
enhancing tubular structures or flow voids within
the cortical sulci with no true nidus within the
brain parenchyma

26. Borden type 2 dural AVF in a 45-year-old woman who presented with sudden loss of consciousness , (a) CT
without contrast shows a left temporo-occipital hematoma with intraventricular hemorrhage , (b) T2
shows multiple flow void vascular structures along the cortical sulci of both occipital regions , there is
white matter edema with T2 hyperintensity in the left occipital lobe with evidence of a resolving
hematoma , no nidus can be identified , (c) Left internal maxillary angiogram reveals a dural AVF in the left
transverse sinus supplied by branches of the left middle meningeal artery , note the associated thrombosis
of the proximal and distal parts of the transverse sinus creating an “isolated pouch” and thereby causing
reflux from the shunt into the cortical veins

27. -Hypoattenuation of the white matter at CT or
hyperintense T2 signal at MR imaging indicates
venous congestion or infarction which may
eventually lead to venous hemorrhage
-Focal enhancement of these areas may also be
observed as a sign of chronic venous ischemia
-Curvilinear subcortical calcifications can be seen at
CT in patients with long-standing cortical venous
reflux, possibly due to chronic venous congestion

28. Classification :
a) Cognard classification
b) Borden classification
a) Cognard classification :
-Correlates venous drainage patterns with increasingly
aggressive neurological clinical course
Type I : Confined to sinus wall, typically after thrombosis
Type II :
IIa : Confined to sinus with reflux (retrograde) into sinus
but not cortical veins
IIb : Drains into sinus with reflux (retrograde) into cortical
veins (10-20% hemorrhage)

29. Type III : Drains direct into cortical veins (not into
sinus), 40% hemorrhage
Type IV : Drains direct into cortical veins (not into
sinus) with venous ectasia, 65% hemorrhage
Type V : Spinal perimedullary venous drainage,
associated with progressive myelopathy
b) Borden classification :
1-Type 1 :
-DAVF drainage into a dural venous sinus or meningeal
vein with normal anterograde flow
- Usually benign clinical behavior
-Equivalent to Cognard type I and II

30. 2-Type 2 :
-Anterograde drainage into dural venous sinus and
onwards but retrograde flow occurs into cortical veins
-May present with hemorrhage
-Equivalent to Cognard type IIb and IIa+b
3-Type 3 :
-Direct retrograde flow of blood from the fistula into
cortical veins causing venous hypertension with a risk
of hemorrhage
-Equivalent to Cognard type III, IV and V

31. 7-Caroticocavernous Fistula :
-Represent abnormal communication between
the carotid circulation and the cavernous
sinus
-Direct CCFs are often secondary to trauma,
most commonly seen in the young male
patients, presentation is acute and symptoms
develop rapidly
-In contrast, indirect CCFs have a predilection
for the postmenopausal female patient and
the onset of symptoms is often insidious

32. Clinical Picture :
1-Pulsatile exophthalmos / proptosis : 75 %
2-Chemosis and subconjunctival hemorrhage
3-Progressive visual loss : 25-32 %
4-Pulsatile tinnitus (usually objective)
5-Raised intracranial pressure
6-subarachnoid hemorrhage, intracerebral
hemorrhage, otorrhagia, epistaxis : 2.5-8.5 %

33. Classification :
Direct : Direct communication between intra-cavernous ICA
and cavernous sinus
Indirect : Communication exists via branches of the carotid
circulation (ICA or ECA)
-Another method is to classify according to four main types
Type A : Direct connection between the intracavernous ICA
and CS
Type B : Dural shunt between intracavernous branches of
the ICA and CS
-Type C : Dural shunt between meningeal branches of the
ECA and CS
-Type D : B + C

34. *Direct : type A
-A direct fistula is due to a direct communication
between the intracavernous ICA and the
cavernous sinus
-There are a number of causes, however
aneurysm rupture and trauma are by far the
most common

35. *Indirect : types B, C & D
-Indirect fistulas are due to communication by
multiple branches between the ICA / ECA and CS
-The are most frequent are type C, with meningeal
branches of the ECA forming the fistula
-They are postulated to occur secondary to
cavernous sinus thrombosis with
revascularization
-Other predisposing factors appear to be
pregnancy, surgical procedures in the region &
sinusitis

36. MRI :
-Findings of CCFs include a dilated CS with multiple signal
intensity void structures that are associated with
proptosis and an enlarged superior ophthalmic vein
-On gradient-echo images, these flow voids shows high
signal intensity
-The presence of flow-related enhancement in the CS on
MRA suggests the diagnosis in the right clinical setting
-Other supporting findings are a dirty appearance of the
retro-orbital fat and enlargement of the extraocular
muscles, due to the presence of intracavernous
communications, very high-flow fistulas may result in
enlargement of both CSs

37. ICA to a CS fistula , axial source image from an MRA shows flow-
related enhancement in the medial (arrow) left CS from a direct-
type fistula

38. MRA shows an enlarged superior ophthalmic vein (arrow)

39. MRA shows a right carotid cavernous fistula (arrow)

40. c) Pial AVF :
-Consist of a direct fistulous communication
between a pial artery and a vein without any
intervening nidus
-They differ from dural AVFs in that they derive
their arterial supply from pial or cortical
arteries and are not located within the dura
mater
Incidence :
-Pial AVFs are more commonly encountered in
children and are frequently associated with
hereditary hemorrhagic telangiectasia

41. Location :
-Pial AVFs are located on the surface of the brain, are
often high flow lesions and in most instances are
associated with dilated venous pouches
Radiographic Findings :
-Clues to the diagnosis of pial AVFs at cross sectional
imaging include the presence of :
a) Dilated vessels, mainly at the brain surface
b) Asymmetric dilatation of the pial feeding artery,
either the MCA, ACA or PCA, which is best seen at
the level of the circle of Willis
-These findings can be used to differentiate pial AVFs
from dural AVFs and may be accompanied by dilated
venous pouches outside the brain parenchyma

42. Pial AVF in a 1-week-old neonate who presented with congestive heart failure , the patient had a family history
of hereditary hemorrhagic telangiectasia , (a, b) Axial T2 reveal enlargement of the right MCA at the level
of the circle of Willis (arrow in a) and a large dilated vascular structure in the right perisylvian region
(arrowhead in b) , findings that are suggestive of a venous pouch , the upper portion of another large flow
void structure is also seen in the posterior fossa , no nidus can be identified , (c) Lateral RT ICA angiogram
reveals a high-flow fistula between an MCA branch and a large venous pouch (arrowhead) , retrograde
flow of contrast material into the basilar artery confirms the presence of another high-flow fistula
(arrows) from the posterior inferior cerebellar artery , the high-flow fistulas and venous pouches are
typical findings in a patient with hereditary hemorrhagic telangiectasia

43. Pial AVF with venous pouches and venous congestion in a 7-year-old boy who presented with
headaches , the patient had a family history of nosebleeds and mucosal telangiectasias
suggestive of hereditary hemorrhagic telangiectasia , (a,b) T2 reveal large dilated vascular
structures in the right perisylvian region suggestive of venous pouches with enlargement of
the right MCA relative to the left side (arrow in b) and no identifiable nidus , findings that are
compatible with a pial AVF , the hyperintense T2 signal of the white matter at the right
frontal lobe (arrow in a) is suggestive of venous congestion , (c) Lateral RT ICA angiogram
reveals a high-flow fistula between an MCA branch and large venous pouches

44. (ii) Malformations without AV shunts :
a) Cavernous Malformation
b) Venous Malformations
c) Capillary Telangiectasia
d) Moyamoya Disease

45. a) Cavernous Malformation :
-Cavernous angioma (Cavernoma)
-Dilated endothelial cell-lined spaces with no
normal brain within lesion
-Usually detectable because cavernous
malformation contains blood degradation
products of different stages

46. Incidence :
-All age group
-60-80 % multiple (may be familial)
-Often associated with an adjacent developmental
venous anomaly (DVA), there is increased risk of
bleeding if a DVA is present, however, the DVA itself
doesn’t have any bleeding risk
-When multiple, cavernous malformations represent an
inherited disorder called familial cavernomatosis
Location :
-80% supratentorial
-Occur anywhere in CNS, common in Pons

47. Clinical Picture :
-Small hemorrhages -Seizures
-Headache secondary to occult hemorrhage
MRI :
-T2 : Popcorn lesion : bright lobulated center with black
(hemosiderin) rim
-Subacute hemorrhage and degraded blood products
within the lesion produce a halo of signal
hyperintensity around the lesion on T1-weighted
images, a useful finding for differentiating cavernous
malformations from hemorrhagic tumors and other
intracranial hemorrhages
-Always obtain susceptibility sequences to detect
coexistent smaller lesions

48. Cavernoma in the postcentral gyrus on T1 , T2 and SWI , notice
popcorn appearance and blooming artifact

49. T2 & T2* gradient echo show multiple cavernomas , notice the popcorn appearance
with peripheral rim of hemosiderin on the T2 , the lesions are almost completely
black on the gradient echo due to blooming artefacts , T2* and susceptibility
weighted imaging (SWI) markedly increase the sensitivity of MRI to detect small
cavernomas , the five black dots in the left cerebral hemisphere on the T2* are also
cavernomas and are not visible on the T2WI

50. (a) Axial T2 shows a large left parietal mass that resembles a popcorn ball with a
hypointense hemosiderin rim (arrows) and loculated hyperintense compartments
(b) Axial T1 at the same level shows multiple high signal intensity compartments in the
lesion , findings suggestive of subacute hemorrhage , a faint halo of high signal
intensity also is visible around the lesion (arrowheads)

51. Cavernous malformation & associated DVA , T1+C show a hypointense , centrally
hyperintense nonenhancing cavernous malformation (yellow arrow) in the left
cerebellar hemisphere , directly superior to the cavernoma (b) is an enhancing
vascular structure with caput medusa morphology (red arrow) representing a DVA

52. Giant cavernous malformation (a) CT without contrast shows a hyperattenuating
complex mass (arrows) in the RT fronto-temporal lobe , (b) T1 shows the mass is
predominantly cystic & hyperintense (representing blood products) , (C) FLAIR
shows that the intracystic contents are primarily hyperintense , there is a complete
low signal hemosiderin ring surrounding the lesion (red arrows) , there is mild
surrounding edema , (d) T1+C shows no appreciable enhancement

53. b) Venous Malformations :
1-Developmental Venous Anomaly
2-Vein of Galen Malformation
3-Venous Varix

54. 1-Developmental Venous Anomaly (Venous
Angioma) :
-DVA is an abnormal vein that provides functional
venous drainage to normal brain
-Venous angiomas per se do not hemorrhage but
are associated with cavernous malformation
(30%) which do bleed
-DVA is a DO NOT Touch lesion, if resected, the
patient will suffer a debilitating venous infarct,
the DVA must be preserved if an adjacent
cavernous malformation is resected

55. CT :
-Only enhanced scans may show linear vein draining to
ependymal lining of ventricle or cortex with inverse
umbrella-shaped (caput medusa) leash of vessels
draining towards anomalous veins
MRI :
-Medusa head or large transcortical vein best seen on
spin-echo images or after administration of
gadolinium
-Location in deep cerebellar white matter or deep
cerebral white matter
-Adjacent to the frontal horn (most common site)

56. T1+C

57. DVA & a tiny cavernous malformation , (a) T1+C shows a subtle curvilinear
enhancing structure (yellow arrow) in the RT frontal white matter
representing a DVA , (b) Susceptibility weighted shows a focus of
susceptibility artifact (red arrow) , suggestive of an adjacent cavernous
malformation

58. 2-Vein of Galen Malformation :
-Complex group of vascular anomalies that
consist of a central AVM and resultant varix of
the vein of Galen (incorrectly referred to as
vein of Galen aneurysm)
Types :
-Two main types exist with the common feature
of a dilated midline venous structure :
1-Vein of Galen AVM
2-Vein of Galen varix

59. 1-Vein of Galen AVM :
-Primary malformation in development of vein of Galen
-AV shunts involving embryologic venous precursors
(median vein of prosencephalon)
-Choroidal arteriovenous fistula with no nidus
-Absence of normal vein of Galen
-Median vein of prosencephalon does not drain normal
brain tissue
-Manifests as high-output congestive heart failure
(CHF) in infants and hydrocephalus in older children

61. 2-Vein of Galen Varix :
-Primary parenchymal AVM drains into vein of
Galen which secondarily enlarges
-Thalamic AVM with nidus is usually the primary
AVM
-Uncommon to present in neonates
-Higher risk of hemorrhage than the vein of
Galen AVM

62. (a) Sagittal T1 shows the markedly enlarged median prosencephalic vein of
Markowski, characteristic of VGAM (arrow), arterial feeders can be seen along the
anterior wall of the vein, (b) the complex arterial maze (arrows) is well seen on this
conventional angiogram obtained with injection of the left vertebral artery, coils
can be seen along the right side of the varix, occluding several arterial feeders

63. CT angiography axial image showing enlarged median prosencephalic vein
(large arrow) with multiple arterial feeders ( small arrows)

64. CT angiography sagittal image showing enlarged median prosencephalic vein
(black arrow) continuing in the falcine sinus (red arrow) with enlarged
confluence of sinuses

65. (a & b) Sagittal reconstructions of CT angiograms showing choroidal type ,
vein of Galen malformation in a neonate , the falcine draining sinuses are
massively enlarged because of narrowing of both sigmoid sinuses

66. CT+C

67. In utero diagnosis of vein of Galen malformation , MRI performed in the third
trimester showing a dilated midline vascular structure in sagittal (a) , axial
(b) and coronal (c) planes

68. T1 T2

69. T1 T2

70. T2, the dilated galenic vein, namely the median vein of prosencephalon (thick
arrow), located midline in the cistern of velum interpositum, drains into
the parietal superior sagittal sinus (thin arrow) via the persistent primitive
falcine sinus (arrowhead)

71. c) Capillary Telangiectasia :
Definition :
-Nests of dilated capillaries with normal brain
interspersed between dilated capillaries
-Commonly coexist with cavernous malformation
-A Do NOT Touch lesion
Location :
-pons > cerebral cortex, spinal cord > other locations
MRI :
-Foci of increased signal intensity on contrast-enhanced
studies
-T2 : hypointense foci if hemorrhage has occurred

72. (a) T1+C Patient with midbrain capillary telangiectasia showing brush-like
enhancement in the right midbrain , (b) Gradient shows subtle increased
susceptibility in the right midbrain

73. GRE T1 T1+C

74. d) Moyamoya Disease :
Definition :
-Uncommon occlusive disease of unknown origin that classically
involves the supraclinoid internal carotid arteries with relative
sparing of the posterior fossa in the early stages
-The term moyamoya syndrome is used in cases in which no
underlying cause (atherosclerosis, Down syndrome,
neurofibromatosis, sickle cell disease or some other condition)
can be identified
-There is usually development of extensive tiny basal perforator
collateral vessels ( the moyamoya vessels ) which have been
described as having a puff of smoke appearance at cerebral
angiography and of transdural collateral vessels

77. 2-Clinical Picture :
-Differs between pediatric and adult
populations:
a) Most children present with transient ischemic
attack or cerebral infarctions
b) Approximately one-half of adults present with
intracranial hemorrhage from rupture of the
moyamoya collateral vessels

78. CT & MRI :
-Imaging include the presence of tiny flow voids,
commonly seen arising from the basal cisterns
and extending into the basal ganglia or the
thalamus
-There is no true nidus embedded within the brain
parenchyma and no dilated vessels
-The diagnosis can be suggested by the presence
of bilateral supraclinoid internal carotid artery
stenosis at MRA and CTA

80. MRA