Vascular Lesions of the Brain

Vascular Lesions of
the Brain
22 APRIL 2014

Contents
 AVMs
 Dural AVF
 CCF
 Cavernoma
 Capillary telengiectasia
 Venous angioma
 Aneurysm
 Moya-moya
 Sturge–Weber Syndrome
 Vein of Galen malformation
 Dissection of Carotid and Vertebral Arteries
 Cerebral Venous Thrombosis

AVMs
 True arteriovenous malformations (AVM’s) are
characterised by the absence of a capillary bed and thus
the presence of a high-flow arteriovenous shunt
 It accounts for approximately 2% of all haemorrhagic
strokes;
 These entity tends to occur in younger patients
 Hospital based autopsy studies have reflected
prevalence rates of up to 600 per 100,000 persons.
 It was generally agreed that the incidence rates for
AVMs are about 1 per 100,000 person years.

AVMs
 Brain parenchyma may be found between the
vessels depending on the size of the AVM nidus,
 A diffuse nidus is more likely to have cerebral
parenchyma within it compared to a tight nidus.
 The most common modes of presentation:
 Haemorrhage
 The most common presentation and occurs in 50-65% of
patients
 The risk of AVM haemorrhage has been calculated to be
between to 2 to 4% per year
 The location of haemorrhage can be either primarily
intraparenchymal (lobar), subarachnoid, intraventricular or
any combination of the above.

AVMs
 Seizures
 occur in 30% of patients
 Generalised seizures or partial seizures with secondary
generalisation.
 Higher risk of seizure if the size of the nidus >6cm
 Headache
 11 to 14%
 Benign headache (same side of the lesion and is usually
non-pulsating)
 The evidence of a sentinel intracerebral haemorrhage.
 Focal Neurological Deficit
 less than 10%
 deficits may be transient, persistent or sometimes
progressive.
 The incidence of aneurysms in relationship to AVM’s is 10-25%

AVMs: Imaging Modalities
 Computed Tomography (CT)
 Atypical pattern of the haemorrhage
 Calcification of AVM vessels
 Intravenous contrast may show a serpiginous area of
enhancement
 CT Angiography (CTA)
 Evaluation of the cerebral vasculature
 3 dimensional imaging

 Magnetic Resonance Imaging (MRI)
 Evaluation of the nidus size and its anatomical relationship, with
MR angiography (MRA)
 MRI’s are best used to identify high flow AVM’s as they show up
as signal voids due to the rapidly flowing blood.
 Functional MR imaging (fMRI) has resulted in the merger of
anatomic and functional detail allowing for significantly improved
pre-operative planning.

 Digital Subtraction Angiography (DSA)
 Gold standard modality in the imaging of AVM’s.
 It has a high spatial (0.2mm) and temporal resolution
(up to 24 frames/s) when compared to other
modalities
 It is the best modality in assessing the dynamic flow
of AVM’s as the speed of contrast passing through
the AVM allows us to assess it as a high or low flow
shunt.
 Accurate detection of intranidal aneurysms
 Invasive technique
 Neurological complications (0.3%)
 Groin haematomas (6.9 to 8.1%)

AVMs: Treatment
 3 main methods include:
 Microsurgical resection,
 Stereotactic radiosurgery and
 Cerebral embolisation.
 Treatment method based on the
classification of AVM’s.
 Widely used grading methods for AVM’s
is the Spetzler-Martin classification

Spetzler-Martin classificationSpetzler-Martin classification

Dural Arterio-Venous Fistula
(d AVF)
 DAVFs account for 10–15% of all intracranial
vascular malformations.
 The fistulas are more frequent among middle-
aged and older patients, though younger
patients and children can be affected.
 DAVFs consist of a shunt between dural arteries
and sinuses, either directly or mediated by
cortical or other sinusal veins.
 DAVF is considered to be an acquired
pathology.
 DAVFs are preceded by thrombosis of a sinus.
 When the lumen recanalizes, microscopic AV
shunts, normally present within the wall of the
sinus, may enlarge and open into the sinus.

(d AVF)
 Many DAVFs remain asymptomatic or
have a benign course.
 In other cases, DAVFs can have a more
aggressive course, characterized by
cranial nerve palsy, ischemia,
hemorrhage, and cognitive disorders.
 Symptoms are related to the location of
fistula with its connecting veins and
venous hypertension.
 Venous connections could be either or
both at cortical and epidural space.
 Cortical venous drainage might be the
cause of intracranial bleeding which is
one of the most dangerous clinical
manifestations.
 If it goes into spinal veins, myelopathy
will be observed.

(d AVF)
 Imaging:
 CT:
 Often normal without CE, engorged veins with CE
 MRI & MRA:
 Numerous flow voids related to fistula or engorged veins
 Cerebral Angiography:
 Gold standard for the diagnosis of dAVF.
 Sinus thrombosis with abnormal arteriovenous fistula
draining into dura or cortical veins, Corkscrew -like veins with
venous hypertensions, enlarged feeding arteries from
external carotid artery

(d AVF)
 Treatment
 Endovascular intervention:
 Feeding artery embolization, abnormal sinus
packing,
 Surgery:
 Fistula resection, dura mater coagulation or
resection
 Radiosurgery:
 Focal irradiation

Carotid–Cavernous Fistulas
 These are the most frequent type of arteriovenous
fistulas and are characterized by a direct shunt between
the intracavernous segment of the internal carotid artery
(ICA) and the surrounding venous plexus of the
cavernous sinus.
 The pathogenesis is commonly a rupture of the artery
and vein, after a penetrating or blunt trauma.
 Spontaneous fistulas can occur: these are commonly
due to a rupture of an intracavernous aneurysm,
frequently linked to an associated angiodysplasia:
fibromuscular dysplasia (FMD), neurofibromatosis, and
Ehlers-Danlos syndrome.

Carotid–Cavernous Fistulas
 Carotid-cavernous fistulas are
characterized by a typical
cavernous sinus syndrome
with ophthalmoplegia, visus
involvement, pulsating
exophthalmos, chemosis, and
bruit.
 The symptoms can appear
acutely or slowly,
progressively days or weeks
after the trauma.
 Ischemia or intracerebral
hemorrhage may occur.

Carotid–Cavernous Fistulas:
Diagnosis and Treatment
 The dilated cavernous sinus and superior ophthalmic
vein can be easily recognized on CT or MRI.
 Angiography, however, is essential for a precise
diagnosis and in planning treatment.
 Carotid-cavernous fistulas are high-flow fistulas with a
rapid injection on the angiogram of the cavernous sinus.
 Depending on the location of the fistula and anatomical
variant, further drainage can be prevalently directed as
follows:
 Anteriorly, in the superior inferior ophthalmic veins, in which the
flow is reversed; extracranially, draining into the facial vein
system; or
 Posteriorly, into the superior inferior petrosal sinuses.

Carotid–Cavernous Fistulas:
Diagnosis and Treatment
 Through intercavernous anastomoses, the contralateral
cavernous sinus may be involved.
 Endovascular treatment with a detachable balloon to
occlude the shunt, which was proposed and developed
by Serbinenko (1974) and Debrun et al. (1975), has
progressively become the therapy of choice.
 The treatment is performed today with a balloon or coils,
which has led to good clinical and anatomical results,
with limited morbidity and mortality

Cavernoma
 Cavernous malformations (CMs) are the second most
common vascular lesion encountered in the central
nervous system (CNS) after venous developmental
malformations (VDMs).
 Cavernous malformations represent 5% to 16% of all
CNS vascular
 Based on large MR imaging and autopsy series, the
overall incidence of CMs is approximately 0.4%-0.9%
 CMs present in a sporadic and familial form.
 The annual bleeding rate in sporadic CMs is estimated at
0.25% to 6.5% per patient-year
 In familial form of CMs, the annual risk of hemorrhage
has been estimated at 13-17%

Cavernoma
 Symptoms usually manifest between the 2nd and 5th
decade, with the mean in the later 4th decade
 A cavernous malformation has no intervening brain
tissue and this characteristic separates it from the
previously described vascular malformations.
 Macroscopically they are well circumscribed and
sometimes have a mulberry appearance.
 Microscopically they are thin walled vascular channels
with no intervening cerebral parenchyma.
 Magnetic resonance with its special sequences, has
allowed a more frequent detection of these lesions in
both symptomatic patients, as well as in asymptomatic
ones.

Cavernoma
 CMs tend to grow through
repetitive lesional
hemorrhages, recanalization
after intraluminal thrombosis
and cavern proliferation
 Hemosiderin deposits and
gliotic reaction are found in the
adjacent brain parenchyma.
 Although a dilated vein may be
found in proximity to the CMs,
no abnormal feeding artery is
seen.

Cavernoma: Imaging
 MRI is the diagnostic tool of choice for
accurate diagnosis of CMs.
 On MRI, CMs appear as a well defined,
lobulated lesion with a reticulated core of
heterogenous signal intensity on T1 and T2
imaging sequences.
 The high intensity signal within the lesion is due to
the presence of hemoglobin degradation products
such as methemoglobin and thrombosis.
 Calcifications, fibrosis, acute and subacute blood
may account for the low intensity signal within the
lesion.
 The mixed intensities have given CMs their typical
popcorn appearance.
 On T2WI and on gradient echo images, a peripheral
ring of hypointensity can be seen, corresponding to
the deposition of hemosiderin and ferritin on the
outer limits of the lesion.
on contrast CT study of brain
shows right frontal
Cavernoma with punctate
calcifications. An adjacent
Gliosis noted.
MRI study of brain shows
right frontal Cavernoma
appears to be complicated
with bleed which has
resolved and is evident by
Gliosis with low signal
intensity hemosiderin staining
on GRE.

Cavernoma: Management
 Conservative management
 Asymptomatic cerebral CMs in the sporadic or familial
form are generally observed with follow-up MRIs
performed at yearly or 2-year intervals.
 Conservative management may also be
recommended for patients with minimal symptoms
 Stereotactic radiosurgery
 Alternative to surgery, especially in deep lesions.
 Its goal is to obliterate the caverns and thereby
prevent rebleeding.
 Studies have documented that the hemorrhage rate
of CMs decreases after a latency of about two to four
years following radiosurgery

Cavernoma: Management
 Surgical treatment
 Control of medically intractable epilepsy, recurrent
overt hemorrhage, and severe focal or progressive
neurological deficits.
 Not for asymptomatic patients, even for CMs located
in an easily accessible region.

Capillary telangiectasia
 The Telangiectasias are similar to cavernous angiomas.
 Unlike the latter, there is brain parenchyma between the
vascular channels.
 The incidence on autopsy is reported to be 0.1–0.15%
 They are frequently associated with cavernous
angiomas,
 Telangiectasias can be found everywhere in the brain
parenchyma and spinal cord, with a predominance in the
pons and basal ganglia.
 The neuroradiological diagnosis is similar to that with
cavernous angiomas.
 Capillary telangiectasias are composed of vessels similar
to normal capillaries with diameters usually less than 30
micrometres in diameter.

Capillary telangiectasia
 The vessel walls do not contain elastica and muscularis
and they are separated by normal brain tissue
 Hypointense on T1 MRI, hyperintense on T2 MRI,
somewhat contrast-enhancing ("blush") on a contrast
MRI or a cerebral angiogram.
 They do NOT have a hemosiderin ring (compare
cavernomas and AVMs);
 NOT associated with cerebral gliosis (compare AVMs)
and do not exert any "mass effect" or pressure on the
local brain.
 They should be left alone unless they are convincingly
growing (unlikely)
 Stereotactic radiosurgery and open surgery should, in
general, NOT be offered following the detection of these
lesions.

Axial contrast-enhanced T1-
weighted MRI demonstrates a
subtle area of enhancement in
the right parietal subcortical white
matter in a patient with capillary
telangiectasia (arrow).
Axial contrast-enhanced T1-weighted
MRI obtained through the pons
demonstrates an area of mild
enhancement without mass effect in a
patient with a capillary telangiectasia.

Venous angioma
 Developmental Venus anomaly
(DVA) also called venous angioma.
 DVA is prevalently located in the
white matter of the cerebral
hemisphere, whereby several
medullary veins converge on a
unique collector draining further
superficially in one of the sinuses or
in one of the subependymal or basal
veins.
 Venous anomalies may represent a
single dilated vein (varix) or multiple
dilated venous channels.
 They are also usually separated by
normal brain tissue and there is no
direct arterial input.

Venous angioma
 Histologically they are endothelium surrounded by a
single layer of fibromuscular tissue
 DVA has been reported as being the most common
vascular malformation detected on autopsy with an
incidence of 2.6%.
 Most DVAs are asymptomatic.
 Hemorrhages can occur, and these are considered to be
due to the associated cavernous angiomas
(Cavernoma).
 On an angiogram, typical DVAs are recognizable in the
capillary–venous phases, where several medullary veins
converge on a large collector
 The arterial phase is normal.

Aneurysm
 Intracranial aneurysms are common
lesions in neurosurgical practice
 Prevalence in the general population
ranging from 0.2 to 9%.
 Descriptions of subarachnoid
hemorrhage (SAH) have been
registered by a "sudden headache
and stage of unconsciousness”.
 The true incidence of aneurysmal
SAH is not known but is estimated to
be around 10/100.000/year.
 This pathology is an important cause
of mortality (50 to 60%) and
morbidity (20% to 30%) in major
series.

Risk factors for aneurysmal SAH
 Aneurysmal rerupture has been associated with even
poorer prognosis, with a mortality rate of 70 to 90%
 The main risk factors for aneurysmal SAH are hypertension, smoking
and alcoholism, however other factors can be also involved as shown
below:
 1. Cigarette smoking.
 2. Hypertension.
 3. Alcohol.
 4. Slight increased risk with
advancing age.
 5. Cocaine abuse.
 6. Oral contraceptives.
 7. Pregnancy.

Signs and symptoms of SAH
 Headache is the most common symptom (80%),
classically described as “the worst headache of my life”,
coming on suddenly and frequently accompanied by
nausea and vomiting
 Meningeal signs such as neck rigidity, Kernig and
Brudzinski signs

 Ocular fundus may reveal retinal
and subhyaloid bleeding (20-
40%), also recognized as
Terson’s sign

Aneurysm
 Other signs and symptoms such as cranial nerves
dysfunction, motor and / or sensitive deficits can help in
the determination of the site of the aneurysm, such as in
those located at the posterior communicating artery
which are often associated with third nerve palsy

Aneurysm: Diagnosis
 The diagnosis of aneurysmal SAH is determined by a
combination of clinical findings and alterations in the
computerized tomography (CT), characterized by
 The presence of blood in the subarachnoid space and
sometimes located intracerebral or intraventricular
 However, in cases where blood is not shown on the CT
scan, it is mandatory to carry out a lumbar puncture (LP)
for collection of cerebrospinal fluid (CSF) and to look for
bloodstained CSF or xanthocromia.
 Once SAH is identified, four vessel cerebral angiogram is
mandatory to be performed

Aneurysm: Management
 Aneurysms less than 3mm are micro-
aneurysms and cannot be either coiled
or clipped.
 Treatment include:
 Clipping +/- clip reconstruction
 Endovascular Coiling +/- stent
assisted
 Coagulation and wrapping
 Bypass and trapping

Moya-moya
 This is a chronic, progressive
cerebrovascular disease, first described
in Japanese patients by Takeuchi and
Shimizu in 1957.
 The term moyamoya, proposed by
Suzuki and Takaku (1969), means
“vague puff of smoke”, unique
radiological findings shown in
conventional angiography
 Despite the fact that the disease is more
frequent in Japanese patients, later
studies showed that it can occur also in
non-Asians.

Moya-moya
 Children and young patients are prevalently involved, but
the disease may also be seen in older patients.
 The two findings are indispensable
 1) steno-occlusive change of the anterior part of the
circle of Willis ring,
 2) the development of the moyamoya vessels that are
supposed to be the abnormally dilated collateral
circulation to compensate the disturbance of main route
of cerebral blood flow.
 It is typically seen in both sides
 Intimal thickening due to proliferation and migration of
smooth muscle cells leads to progressive occlusion of the
intracranial distal ICA, with extension also to the M1 and
A1.

Moya-moya
 The etiology of the disease is not known.
 Moyamoya disease can occur in different pathological
conditions:
 Vasculitis with or without an autoimmune mechanism,
 Postirradiation state,
 Neurofibromatosis,
 Hemoglobinopathies,
 Atherosclerosis.
 Genetic factors probably also play some role.
 Angiography is the essential method for identifying the
disease.
 Moyamoya disease has a progressive character, and it
leads to ischemic stroke and hemorrhage.
 The latter is frequently due to small aneurysms present
in the basal network.

Moya-moya: Treatment
 2 ways of surgical revascularization:
 1) direct bypass surgery
 2) indirect bypass surgery
 Direct bypass surgery means anastomosis between the
superficial temporal artery (STA) and the cortical branch
of the middle cerebral artery (MCA) or the anterior
cerebral artery.

Moya-moya: Treatment
 Indirect bypass surgery
 The temporal muscle and other vascularized tissue
such as the galea aponeurotica and periosteal
membrane should be preserved without injury to the
feeding arteries such as the STA, deep temporal
artery and middle meningeal artery, covers the brain
surface with these vascularized tissues.
 It takes several months to develop the angiogenesis
from these tissue to the brain surface.
 These angiogenesis is not always constantly
expected in all cases.
 This indirect bypass surgery is more efficient in
pediatric moyamoya cases

Sturge–Weber Syndrome
(Encephalotrigeminal
Angiomatosis)
 Sturge-Weber syndrome is a familial neurocutaneous
disease, characterized by a facial vascular nevus in the
trigeminal distribution (facial port-wine stain), mainly in
the first branch, a retinal angioma, and leptomeningeal
angiomatosis.
 The pathology consists of a network of thin-walled
capillaries and venules lying between the pial and
subarachnoid membrane.
 There is also typically a paucity of cortical veins; this is
responsible for the stasis and progressive hypoxia of the
cortex, which becomes atrophic and partially calcified.

Angiomatosis)
 Children and teenagers with SWS often develop
neurologic problems including seizures, migraines,
stroke-like episodes, learning difficulties or mental
retardation, visual field cuts, and hemiparesis.
 Any child with a facial port-wine stain in the V1
distribution, we recommend should have a head CT to
image the calcification and an MRI of the brain with and
without contrast to detect the angioma
 The combination of the facial angioma and seizures are
diagnostic.
 The typical CT findings are cortical calcifications often in
a gyral pattern and atrophy, although these findings may
not be present in neonates or infants.

Angiomatosis)
 MRI with gadolinium contrast demonstrates the
abnormal intracranial vessels.
 The leptomeningeal angioma is typically ipsilateral to the
facial nevus.
 Bilateral brain lesions occur in at least 15% of patients.
 Hemispherectomy is the recommended treatment for
newborns with intractable seizures.
 The procedure improves seizure control and promotes
better intellectual development

Vein of Galen malformation
 The pathogenesis of this malformation, which can be
termed a true vascular malformation, is a malfunction in
embryogenesis, involving the median prosencephalic
vein (PV).
 In accordance with the radioanatomical studies, the PV
receives drainage from the deep cerebral structures and
choroid plexus, and it drains further into the falcine sinus.
 The vein disappears in a period between the sixth and
eleventh weeks, and it is replaced by the vein of Galen,
arising from unification of the caudal remnant of the PV
with the developing internal cerebral vein.
 The vein of Galen drains further into the straight sinus
(SS).

Vein of Galen malformation
 Failure of regression of the PV results
in hypoplasia of the SS, with the
venous drainage frequently diverted
into a persistent falcine sinus
 The cause of the abnormal
arteriovenous shunts remains
unknown.
 The malformation may be linked to
an embryogenetic error involving the
choroidal arteries, which, in the same
embryonic period when the PV is
prominent, are the most active
arterial structures present; thus, they
are the most vulnerable to
maldevelopment.

Vein of Galen malformation:
Diagnosis and treatment
 CT and MR allow easy identification of this kind of
malformation.
 Selective and super-selective angiography is essential
for precise study.
 Angiographic study and endovascular treatment should
be performed earlier if rapid clinical deterioration,
particularly as a result of heart failure, occurs.

Dissection of Carotid
and Vertebral Arteries
 Spontaneous dissection is today a well-
recognized pathology that is responsible
for stroke in many cases.
 Its incidence is reported to be three to
four cases per 100,000 persons yearly
 Young and middle-aged patients are
predominantly affected.
 The lesion is characterized by a
subintimal hemorrhage, leading to
stenosis or occlusion of the artery.
 The hemorrhage can involve the outer
media or the subadventitial layer,
resulting in the formation of
pseudoaneurysms.

 Dissection occurs because of a primary intimal tear,
allowing the blood to pass into the arterial wall.
 Primary intramural hemorrhage can also occur through
rupture of the vasa vasorum.
 The pathogenesis of dissection can be traumatic, but in
the spontaneous form, the pathogenesis is not
completely clear.
 Structural changes of the arterial wall, associated with
mechanical factors, are probably involved.
 It is well known that dissection occurs frequently in
patients with fibromuscular dysplasia (FMD), Ehlers-
Danlos syndrome, Marfan syndrome, and lupus
erythematosus

 Extracranial ICA: 2–3 cm distal to the bifurcation is the
most frequent site of dissection.
 The second-most frequent location is the extracranial
vertebral artery.
 Intracranial dissection is less frequent.
 Advanced age can be a factor, but there is a
predominance of young patients.
 The vertebrobasilar sector is more frequently affected.
 Dissection usually involves the first intracranial segment
of the VA, sometimes as an extension of extracranial
dissection.
 Dissection of the basilar artery is less common: it can be
primary or a secondary extension of dissection of the
VA.

 The treatment of extracranial lesions is controversial
since an important aspect is normalization of the vessel
lumen in many cases.
 This is particularly true when stenosis is present.
 Recanalization can also occur more rarely in cases of
occlusion.
 When a pseudoaneurysm is present, it commonly
remains unchanged or can enlarge later.
 In the acute phase, conservative medical therapy that
avoids intracranial embolism is preferred in many
centers.

 Endovascular therapy may be performed later if the
stenosis or pseudoaneurysm remain.
 In selected cases, when stenosis is present but the
lumen is maintained and an embolic intracranial
occlusion is recognizable, selective endovascular
thrombolysis can be performed.

Cerebral Venous Thrombosis
 The true incidence of central venous thrombosis (CVT)
remains unknown.
 Causes
 infection,
 Intracranial extension of infectious diseases
involving the skin-bone cavities of the craniofacial
area
 General bacterial septicemia or viral infection,
especially due to HIV and cytomegalovirus.
 During pregnancy,
 In puerperium,
 Usage of oral contraceptives.

 Causes
 Pathologies of the red blood cells, such as
thrombophilia, polycythemia, sickle cell disease,
leukemia, and lymphoma, and in many coagulation
disorders, such as protein C and S deficiency and
disseminated intravascular coagulation.
 Behçet’s disease,
 Systemic lupus erythematosus,
 Severe dehydration and cardiac failure.
 Cranial trauma and neurosurgical intervention.
 Intracranial tumors, especially meningiomas, can
involve the adjacent sinus and cause thrombosis

 The superior sagittal sinus (SSS) is the venous channel
most commonly involved, followed by the transverse
sinus.
 The thrombosis can be limited to the sinus, and the
clinical presentation may frequently be characterized by
clinical symptoms owing to intracranial hypertension,
such as headache and visual disturbances.
 Cortical vein tributaries of the thrombosed sinus can be
secondarily involved as a result of retrograde
propagation of the thrombus, which commonly leads to
ischemia.

 CT and MRI allow the detection of changes to the brain
parenchyma in the form of hemorrhagic and/or
nonhemorrhagic infarcts, uni- or bilateral, single or
multiple, with various locations depending on the site and
extension of the CVT.
 White matter hypodensity on CT and hyperintensity on
T2 images on MRI, which indicate edema of a preceding
venous infarct, is also a sign suggesting venous
thrombosis.
 On CT, an abnormal hyperdensity can be recognized at
the level of the torcular herophili, SSS, and lateral sinus.
 In doubtful cases, or whenever a more specific diagnosis
is required, angiography remains a practical diagnostic
method.

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