Anatomy and intervention in cerebral vasculature

ANATOMY AND INTERVENTION OF CEREBRAL VASCULATURE

Presenter: Charusmita ChaudharyModerator: Dr. R.K.Gogoi

Deptt. of Radio Diagnosis

NORMAL ANATOMY

• ARTERIAL SUPPLY• 2 Internal Carotid Artery• 2 Vertebral Arteries

• VENOUS DRAINAGE• Outer/superficial segment : Scalp vein • Intermediate segment : diploe, emissary , meningeal

and dural sinus• Inner segment :Cerebral Veins (Superficial & Deep)

Branches of Left External Carotid artery

Sup thy A

Lingual A

Facial A

Occ. A

STA

In Max A

Fac. A

Ling.A

INTERNAL CAROTID ARTERY5 ARBITRARY

SEGMENTS EXTRACRANIAL

• carotid bulb• cervical segmentINTRACRANIAL• petrous segment• cavernous

segment• supraclinoid

segment C5

C4

C3

C2

C1

PA

Internal carotid artery Lateral view AP VIEW

ICA

CERVICAL

PETROUSCAVERNOUS SUPRACLINOID

MANDIBULOVIDIANCAROTICOTYMPANIC

MENINGO HYPOPHYSEAL LATERAL MAIN STEM CAPSULAR(Mc Connell’s)

TENTORIAL(BERNASCONI)

DORSALMENINGEAL

INFERIOR HYPOPHYSEAL

SUPERIOR HYPOPHYSEALOPHTHALMIC

POSTERIOR COMMUNICATINGANTERIOR CHOROIDAL

ANTERIOR CEREBRALMIDDLE CEREBRAL

CIRCLE OF WILLIS• Grand Vascular Station of the

Brain• Classical –18% to 20% COMPONENTS• Internal carotid arteries• Horizontal segments of Anterior

cerebrals(A1)• Anterior communicating artery• Proximal segments of posterior

cerebrals(P1)• Posterior communicating

arteries• Basilar artery

Anterior cerebral artery (ACA)

The ACA is divided into five segments A1 segment is located between the

ICA bifurcation and the ACoA. A2 segment extends from the ACoA

to the region between the rostrum and the genu of the corpus callosum

(GCC)A3 segment curves around the GCC

and ends at the rostral part of the body of the corpus callosum.

A4 and A5 segments follow the superior surface of the corpus

callosum with a virtual plane of division at the level of the coronary suture.

Branches of ACA

• A1- medial lenticulostriate artery• ACoA- Perforating branches• A2- Recurrent artery of Heubner (RAH) Orbitofrontal artery Frontopolar artery• A3- Pericallosal and Callosomarginal a.• A4 & A5- Cortical branches

ACA

MIDDLE CEREBRAL ARTERY• Larger terminal branch of ICA• Run laterally in stem of lateral sulcus• Curves on superolateral surface & • Runs backwards in depth of posterior

ramus of lateral sulcus• M1 segment =horizontal segment from origin

to its bifurcation (it is in sylvian fissure)• M2 segment =lacunar segment -in the

insula loops over insula—laterally to exit from sylvian fissure

• M3 segment = opercular branch-from sylvian fissure & ramify over cerebral cortex

• Anomalies of MCA are uncommon

MCA

POSTERIOR CEREBRAL ARTERY

• P1-Peduncular/Precommunicating• P2-Ambient segment• P3-Quadrigeminal segment• P4-Cortical branches

2 major terminal br of PCA—parieto occipital art & calcarine art

PCA

POSTERIOR FOSSA

• Vertebral arteries

• Basilar artery

Vertebral arteries

• Originate from the subclavian arteries.

• Left VA is dominant in 60% cases

Branches • Extracranial -numerous branches to the

meninges,spinal cord & muscles -Posterior meningeal artery• Intracranial -Anterior spinal artery -Posterior inferior cerebellar A Anterior medullary Lateral medullary Tonsillomedullary Telovelotonsillar Cortical branches

BASILAR ARTERY• Right and left VA unite to

form basilar artery• Courses infront of pons

(Prepontine cistern) & terminates in the interpeduncular cistern

• 3cm in length,1.5 to 4mm in width

• >4.5mm width-abnormal

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Normal VARIANTS

1. Fenestrations and duplications,2. Variants of the circle of Willis,3. Persistent carotid-basilar anastomoses4. Anomalies identified in the skull base.

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Duplication of the anterior communicatingArtery each vessel originating separatelyfrom an anterior cerebral artery.

Fenestration of the anterior communicatingartery

Fenestrationsof the anterior cerebral

artery

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Normal Variants of the Circle of Willis

Trifurcation of the anterior cerebral arteryAzygos anterior cerebral artery

Bihemispheric anterior cerebral artery

Absence of an A1 segment of the anterior cerebral artery

Hypoplasia of an A1 segment of the anteriorcerebral artery

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Absence of the anterior communicating artery

Accessory middle cerebral artery

Early bifurcation of the middle cerebral artery.

Bilateral fetal posterior cerebral

arteries

CT angiogram shows a posterior communicatingartery (arrowhead) that arises

from the apex of a funnel-shaped infundibulum (arrow)

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Persistent Carotid-Basilar Artery Anastomoses

Persistent Trigeminal Artery

CT angiogram depicts a hypoglossal artery (arrowhead) that arises from the proximal internal carotid artery (arrow)

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Normal Variant Arteries in the Skull Base1. Persistent stapedial artery,2. Aberrant internal carotid artery 3. Hypoplasia or agenesis of the

internal carotid artery.

VENOUS ANATOMY

• Dural sinuses• Cerebral veins

DURAL SINUSES

• Superior sagittal sinus• Inferior sagittal sinus• Straight sinus• Transverse sinuses• Occipital sinus• Tentorial sinuses• Sigmoid sinuses• Cavernous sinuses

VENOUS SINUSES

CAVERNOUS SINUS

• Hexadron--shaped space• Either side of sella turcica • Along convergence of the sphenoid bone & petrous

bone.

Cerebral veins• Superficial cortical veins• Near vertex they cross Subdural Space to enter SSS• Most are unnamed

Superficial Middle cerebral vein( along sylvian fissure)

Vein of Trolard Vein of Labbe• Deep cerebral veins Vein of Galen Basal veins of Rosenthal Subependymal / Medullary veins

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BLOOD SUPPLY TO RELEVENT PARTS OF BRAIN• In general-cortical branches of 3 cerebral art• Motor area-frontal cortical branch of MCA; Precentral

area and paracentral lobule-anterior cerebral artery• Auditory area-temporal cortical branch. Of MCA• VISUAL AREA-occipital cortical branches of PCA• Speech area –cortical branches of MCA

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IMAGING TECHNIQUES

• Conventional Angiography• Digital Subtraction Angiography• Ultrasonography• CT Angiography• MR Angiography

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Conventional angiography

• It is gold standard because of the outstanding resolution and anatomical nature of the information

• Main disadvantage is it is a invasive procedure and is associated with complications

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Sites :• Femoral artery• Popliteal• Axillary• Brachial • Radial

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Contraindications• Pregnancy• Anticoagulant therapy and bleeding diathesis • Hepatic and renal failure• Systemic hypertension, cushing syndrome• Connective tissue disorders

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Digital subtraction angiography

• DSA have arisen as a result of digital data acquisition, storage and processing.

• The technique uses lower doses of contrast medium because of superior contrast resolution.

• Fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in bony or dense soft tissue environment

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Digital Subtraction Angiography (DSA)• Images produced using

contrast medium by subtracting 'pre-contrast image' from later images with contrast

• Vessels are subtracted “live” –instantly see non-bony superimposed images

• The major disadvantage of DSA is reduced spatial resolution.

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ULTRASONOGRAPHY

• EQUIPMENT :• High resolution linear array transducer

• Used in cases of infants for evaluation of the brain parenchyma

• Windows :• Anterior fontanelle• Posterior fontanelle• Mastoid

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CT Angiography provides acomprehensive analysis of the vascular anatomy including the location, size, and length of the

arteries and veins.

CT Angiography is used to detect;• Dissections• Aneurysms

• Plaque• Stenosis

• Morphological layout andaberrations

• Pre and Post surgical assessments

CT ANGIOGRAPHY

Optimal image quality depends on two factors:CT angiography technique (scan protocol, contrastmaterial injection protocol, image reconstructionmethods) and data visualization technique(image postprocessing).

ADVANTAGES ARTEFACTS

• The more slices that can be acquired per rotation• The longer the volume that can be

scanned• The higher the resolution possible• The better the reproduction of 2D

and 3D reconstructions• The greater the detail available in

all 3 axis (x,y and z)• Patient comfort• Non invasive investigation• Easily available to all levels of

socioeconomic status

• Motion artifacts reduced by faster scanning

• Stair-step artifacts in 3D reconstructions reduced by using thinner slices

• Partial volume artifacts reduced by using thinner slices

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POST PROCESSING• Coronal and Sagittal MPR (multi planar

reconstructions)

• Shaded surface display, or surface rendering, is an algorithm that provides a good 3D impression ofthe surface of an

object.3D volumetric images with rotational

images comprising of bone and non bonebackgrounds.

• MIP (Maximum intensity projections)

• Measurements

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constitutes group of MR imaging techniques that can be used to directly image flow in arteries, veins, and cerebrospinal fluid.

Time-of-flight imaging is susceptible to saturation effects, and short Ti substances may simulate flow. • Two-dimensional time-of-flight imaging is useful in cranial venography in

assessing the patency of the dural sinuses or venous drainage from an arteriovenous malformation.

• Three-dimensional time-of-flight images depict small and medium-sized aneurysms.

Phase-contrast imaging has excellent background suppression, allowsvariable velocity encoding, and provides directional flow information.• Two-dimensional phase-contrast imaging is useful in the assessment of the

patency of major vascular structures. • Three-dimensional phase contrast imaging (with 30-cm/sec velocity

encoding) is also useful in depicting small and medium-sized aneurysms• Cine Phase contrast imaging – hemodynamic flow information. Allow imaging

of csf, venous and arterial flow.

MR ANGIOGRAPHY

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Vascular Interventional procedures of brain

Part II

INTRODUCTION:• Interventional and Endovascular Neurology is the Neurological

subspecialty focused on endovascular and other minimally invasive approaches to the diagnosis and management of vascular and non-vascular neurological diseases.

• The section is committed to advancing all diagnostic and therapeutic interventional procedures that involve the neurological patient community and to support education and research initiatives that will expand this field.

• Endovascular therapies include1. Embolotherapy 2. Cerebral revascularization Non vascular aspects of interventional neuroradiology include pain

management, percutaneous biopsies and vertebroplasty.

• Cath lab.-known as “operating room” or “special

procedures room”.

• Radiographic Imaging Equipments• Biplane angiography with digital subtraction

ability, high resolution image intensifier is recommended. Digital Road map fluoroscopy capability is mandatory, preferably with simultaneous live unsubtracted imaging . Now a days 3D CT is used too.

• Critical care of patients undergoing endovascular and interventional procedures.

VASCULAR INTERVENTION:• Embolotherapy continues to evolve in its active

consideration in the preoperative management of aneurysms, vascular malformations and vascular tumors.

• This progressive increase in demand has been principally as a result of development of newer microcatheter delivery systems and of safer and more varied embolic agents.

• more target specific embolization with a greater degree of preservation of adjacent normal vascular anatomy.

• These include particulate emboli, coils, balloons, tissue adhesives, non adhesive agents, sclerosing agents and chemotherapeutic agents.

Embolic agentsClassification:I. Particulate embolic agents( agent of choice). Absorbable Non Absorbable II. Mechanical embolic agentsIII. Liquid embolic agents.Absorbable agent:Gelfoam( Powder /sheet), AviteneUse: topical thrombotic agent in conventional surgery. to "protect" normal vessels.Non absorbable: PVA(150 to 1000 microns), particles (Ivalon,

Biodyne, Contour Emboli).• PVA: small( embolization of vascular tumors) and large

size( occlusion of larger, high flow vascular malformations). MOA—Adhere to vessel wall(lumen occluded),necrotising

vaculitis. Temporary effect—Weeks to Month

• Recently, a newer class of microembolic agent has been introduced

• Soft, smooth surfaced, deformable particles ( Embospheres (Microsphere) and Bead Block (Terumo))

• tend to ovalize when confined, a trait that makes these agents more effective in more distal embolotherapy.

• ADV: do not adhere to vessel walls as do crystalline PVA particles, particles are more likely to reach the capillary bed of the tumor.

Bead Block

COILS :Guglielmi detachable micro coil. (GDC)• Platinum micro coils soldered on stainless steel micro

wires. once in desired position detached by passing Direct current which causes electrolysis at the soldered site.

• can be positioned, withdrawn and repositioned repeatedly until the desired position is obtained.

Advantage: Coil can be withdrawn before final placement.

The Hydrocoil (Microvention) is unique in that it is coated with a hydrogel that expands after deployment.

BALLOONS• Latex and silastic balloons• Advantages: 1) the ability to occlude a vessel at a precise location 2) the ability to flow navigate attached, partially inflated

balloons to distal locations along a tortuous course3) the ability to rapidly occlude vessels larger than the

caliber of the catheter 4) the ability to inflate, deflate and reposition repeatedly until

the desired position is achieved.

LIQUID EMBOLIC AGENTS• n-butyl cyanoacrylate (NBCA)• Histoacryl• This agent will rapidly polymerize on contact with any ionic

substance such as blood, saline, ionic contrast media and vessel epithelium.

• ADV:rapidly occlude high flow arteriovenous malformations with a more permanent result

• DISADV:The catheter must be rapidly withdrawn after each injection of NBCA, resulting in frequent, time consuming catheter exchanges

• Onyx: non adhesive liquid embolic agent safer and effective than NBCA

SCLEROSING AGENTS• Absolute ethanol• Sotradecol (sodium tetradecyl sulfate) behaves similarly to

alcohol, but with less associated pain.• Hypertonic saline and glucose solutions are also effective

sclerosing agents that work rapidly in both the arterial and venous systems.

• The results of embolotherapy with ethanol when compared to the particulate agents and NBCA have shown a more permanent occlusion of abnormal vessels without the inherent risks associated with tissue adhesives.

CEREBRAL REVASCULARIZATION…..• Intra-arterial cerebral revascularization incorporates several

new technologies and newer applications of techniques that have been well established in peripheral revascularization. The focus on acute stroke reversal offers an exciting new aspect to interventional neuroradiology.

Vascular Interventional procedure of brain Endovascular procedures. Direct percutaneous procedures. Endovascular procedures:1. Endovascular technique for lumen restoration.2. Endovascular technique for lumen obliteration.3. Endovascular treatment of A V shunts.4. Endovascular treatment for vein of galen aneurysal malformation.5. Endovascular treatment of dural arteriovenous shunts.6. Brain tumour embolisation and chemotherapy. 7. epistaxis endovascular therapy: Embolization of refractory head and

neck bleeds.8. WADA and functional testing.9. petrosal venous sinus sampling for Cushing disease10. pseudotumor cerebri endovascular therapy with venous sinus stenting11. endovascular repair of traumatic head and neck vascular injuries

Direct percutaneus procedures:

(1) Image guided Embolisation of tumour.(2) Image guided embolisation of AVM.(3) Image guided photodynamic therapy.

Hyperacute ischemic stroke 1)Intra-arterial thrombolysis : It involves the direct infusion of thrombolytic agents into

the occluding thrombus . Higher local concentration of drug.• Lower systemic concentration.• Fewer extracranial haemorrhagic complications. • Faster and more complete recanalisation .• This allows a longer time window of 3–6 hours or longer if

perfusion studies are favourable.

Thrombolytic agents: 1) Recombinant

tissue plasminogen activator (rTPA).

2)Streptokinase. 3)Urokinase. 4)Pro-urokinase. 5) Ancord .

1)Microguidewire applied

to disrupt the clot facilitate the action of the thrombolytic agent.

2) Clot retrieval devices or Snare which may actually extract the thrombus from the occluded artery, achieving reperfusion much more readily.

2) Mechanical procedures

The BONnet consists of a self-expanding nitinol braiding with polyamide filaments passing through the interior to enlarge the surface area and enable better fixation of the thrombus mass. The system can be either put distal to the thrombus or released into the thrombus. B, The CRC is based on a fiber work of polyamide filaments whose lengths fromproximal to distal end increase. The CRC has an additional nitinol thread cage at the proximal end of its fiber brush. This nitinol cage gives it a higher radial range. C, ThePhenox pCR is based on perpendicularly oriented polyamide microfilaments that create anattenuated palisade.

The Penumbra System is based on an aspiration platform that includes reperfusionmicrocatheters connected to an aspiration pump. A teardrop-shaped separator is advanced and retracted within the lumen of the reperfusion catheter to debulk the clot for ease of aspiration.

Recent mechanical thromolitics

. 3) Balloon Angioplasty or

stent placement If thrombus is

superimposed upon a stenosis. (Atherosclerotic plaque).

Solitaire FR stent (ev3). A self-expanding stent that can be fully deployed and then completely retrieved

Disadvantages Additional time delays. Risks of procedure Arterial embolisation. Arterial perforation. Haemorrhagic

infarction. Retroperitoneal

haematoma. Groin haematoma.

Collectively risk estimated -- 5%

Terminal basilar artery occlusion

• A. Left Vertebral Artery Injection demonstrating extensive clot in the basilar artery .

• B. Following Urokinase via a microcatheter there is complete resumption of normal flow.

TREATMENT OF CEREBRAL VASOSPASM

Cerebral vasospasm represents a significant cause of morbidity and mortality in patient with subarachnoid haemorrhage leading to ischemic deficits.

Medical treatment(Triple H ) Hypertension

Hypervolemia Haemodilution

Endovascular treatment: (1)Pharmacological relaxation of spastic vessel by Selective

intra-arterial papavarine infusion. (2) Mechanical dilatation of spastic segment (balloon

dilatation).

• Cerebral vasospasm (MCA)• Treatment----Balloon dilatation

Angioplasty and stenting of extracranial and intracranial vessels.

Indications• Carotid stenosis(>70%)• Vertebro basilar artery stenosis.• MCA stenosis(>50%) Purpose: Reduce incidence of recurrent stroke (TIA).

Percutaneous transluminal angioplasty(PTA)

Pre treated with antiplatelet agents.

Under LA via femoral artery. The patient is systemically

heparinised and the carotid artery catheterised, a guide wire crosses the stenosis, a protection device is deployed . Balloon inflation (8 atmospheric pressure for 10 sec) deflated if significant stenosis persists repeat procedure for 2 to 3 times.

Clopidogrel and aspirin are maintained for three months.

Stenting• Method of choice• Under LA• Pre operative antiplatelet therapy(Aspirin and

clopidogrel)• Following pre operative angiography ,a

guiding catheter(6Fr) is placed to common carotid artery the stenosis is crossed with a soft tip guidewire,a protection device is deployed .The stenosis is predilated using an angioplasty balloon, and a stent is deployed across the stenosis and redilated.

pathophysiological process of carotid artery dissection proceeding from the acute stage to either spontaneous healing (1), formation of false lumen (2), residual stenosisof varying degree or complete occlusion (3), and formation of a pseudoaneurysm (4). A stent is used in cases not responding to medical therapy either to relieve a hemodynamically significant stenosis, to occlude a false lumen, or to serve as a scaffold to enable coilembolization of a wide-necked pseudoaneurysm.

Carotid Cavernous sinus fistulaCarotid cavernous fistulas (CCFs) result

from spontaneous or acquired , abnormal connection(s) between the cavernous ICA and venous channels of the cavernous sinus, and are either high or low flow.

trauma

Treatment modalities: Type A—High flow type Detachable balloons is the

treatment of choice for most type A CCFs .The currently available latex balloon is deployed up the ICA, through the defect and inflated within the cavernous sinus, occluding the fistula and preserving the ICA.

Barrow’’s Classification (1985)

Carotid cavernous

fistula

Routes –Trans venous (Preferred)—Femoral vein—inferior petrosal sinus cavernous sinus-Platinum micro coils with attached dacron fibres is used.

Trans arterial route---GDC coils are used to reduce the risk of recoiling in the ICA.

Transcatheter coil embolisation-

Liquid embolic agents Onyx can be deployed through the micro catheter

via venous route into the cavernous sinus, with balloon protection (non-detachable) in the ICA .

Type B—Low flow Carotid cavernous sinus fistula Polyvinyl alcohal (PVA)---150—250 micron Size . selective embolisation of external carotid artery feeders

is done. If Recanalisation,, occur, transvenous coil occlusion of

the cavernous sinus either through the jugular vein and inferior petrosal sinus or through the superior ophthalmic vein achieves cure in most patients.

Carotid compression maneuver Facilated thrombus formation.

Endovascular treatment of intracranial aneurysms An aneurysm is a sac filled with

blood which is in direct communication with the lumen of an artery.

True AneurysmLocal dilatation of the artery.

False aneurysm Sac with walls formed of condensed perivascular connective tissue which communicate with the artery through an aperture in its wall.

Common site of intracranial Aneurysm

What to choose ?• • This decision needs to be made withknowledge of:‐‐‐ the safety and efficacy data‐‐‐the patient’s expected longevity‐‐‐aneurysm factors – size‐‐ configuration‐‐ location• ‐‐‐the operator’s experience.• Equally important to consider whether the aneurysm• ‐‐‐unruptured• ‐‐‐ruptured• This complex decision requires entertaining all the variables, ensuring

that patients receive the most appropriate care .

• Clip vs Coil

Coil embolisation: Through trans-arterial

route a micro catheter is placed in the lumen of the aneurysm-through the micro catheter ,soft platinium coils are packed in the aneurysm.

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Large ruptured aneurysm, pre embolization (A), and post embolization with GDC coils ( B&C).

Assisted aneurysm coiling techniques, including balloon assist (A) (Hyperform balloon catheter, MTI) andNeuroform stent assisted technique (B,C) ( Target Therapeutics Corp / Boston Scientific )

Newer technique to reduce coil compaction and recanalisation

• Coils with more complex shapes.• Bioactive coils (coated with polyglycolic polylactic acid). • Hydrogel coils.• Radioactive coils (incorporated with P32 emitting ß

radiation).

• When patency of the parent vessel cannot be assured (Fusiform or serpentine ,wide-necked aneurysm,false aneurysm)-Vessel may be permanently occluded by balloon or coil embolisation with prior test occlusion.

.

Giant Aneurysm Size more than 2.5cm.• Giant aneurysms are often sub-optimally treated using coils

alone. • The accepted treatment ----parent vessel occlusion. • Trial balloon occlusion (TBO) . • When parent vessel occlusion cannot be tolerated. Surgical bypass procedures. Embolisation (high density onyx). stent .

Parent vessel (left ICA) occlusion in the management of a giant cavernous carotid aneurysm.

Endovascular treatment of cerebral AVM Arteriovenous malformation (AVMs) are a complex

conglomerate of abnormal arteries and veins. They lack an intervening capillary bed and there is resultant high flow arteriovenous shunting through one or more fistulae.

Therapeutic options 1) Neurosurgery 2) Embolisation 3) Stereotactic radiosurgery. Aim of treatment 1)Obliterate the AVM completely .

2)Eliminate the risk of haemorrhage. 3)Reduce the effects of steal or venous

congestion .

Spetzler Martin grading system (Grade 1 to 5) Reflects the degree of surgical difficulty and risk of surgical

morbidity and mortality, and the scale is based upon AVM size, venous drainage, and location .

AVM Size--- Small ---- 0 to 3 cm - 1 point. Medium --3 to 6 cm - 2 points. Large ----- > 6 cm - 3 points. AVM location--- Non-eloquent region -- 0 point. Eloquent region --------1 point. Pattern of venous drainage--- Superficial ----------0 point. Deep -----------------1 point.

Treatment rationale: Grades 1 and 2 and some grade 3 ---surgery recommended.

Grade 3 AVMs with deep inaccessible feeders, surgery with embolisation or stereotactic radiosurgery is considered .

Grade 4 and 5 AVMs is usually multidisciplinary

Embolisation under general anaesthesia. Superselective catheterisation of the feeding

arteries using a microcatheter with or without the aid of a micro guidewire.

Liquid embolic agents are generally used, either onyx or n-butyl Cyano acrylate (NBCA).

other embolic agents like balloon,Liquid coil can be used.

Onyx embolisation of a right perisylvian AVM

Onyx embolisation of a right perisylvian AVM

A middle aged patient presenting with an AVM near the visual area of the left hemisphere which hemorrhaged once. Presurgical embolisation was conducted to reduce the size of the AVM. Pre-embolisation image A versus post embolisation B shows the substantial reduction in size. She had an excellent outcome from surgery.

Before Treatment

Following Embolisation in preparation for surgery

Dural AV fistula Dural arteriovenous fistulas (DAVFs) abnormal

arteriovenous connections within the dura, usually within the walls of a dural sinus .

• They are acquired lesions idiopathic most common venous sinus thrombosis and/or venous hypertension.

• Thrombosis triggers the stimulation of angiogenesis and engorgement of microscopic arteriovenous channels that normally exist in the dura.

• The cavernous sinus, transverse and sigmoid sinuses are most often implicated, but any sinus may be involved ..

• Premature visualization of intracranial veins orvenous sinuses during arterial phase-Characteristic

Cognard’s classification

• Type I includes DAVFs which drain into a sinus with normal antegrade flow.

• Type II DAVFs --insufficient antegrade flow with reflux into either venous sinuses (IIa), cortical veins (IIb), or both (IIa+b).

• Type III fistulas drain into cortical veins without venous distension.

• Type IV drain into cortical veins with venous ectasia.

• Type V drain into spinal perimedullary veins.

Management • Type I fistulas --carotid or occipital artery

compression , arterial embolisation using PVA particles

Type IIa treatment of choice is arterial embolisation of ECA feeders using PVA particles

• types IIb and IIa+b --Transvenous coil occlusion of the involved dural sinus.

• Types III and IV---endovascular occlusion of the draining cortical vein itself using coils may occlude the fistula preserving dural sinuses.

Transvenous coil occlusion dural arteriovenous fistula

Vein of galen Aneurysmal malformation

types—1)Direct AVM--Choroidal

arteries/Thalomoperforate actually communicate with the vein of galen.

2)Indirect ---AVM in the thalamus or mid brain veins drain into the vein of galen.

Intervention If possible intervention deferred to allow growth of the

child, as intervention in neonate is difficult and hazardous .

Criteria for neonatal or infantile intervention: Cardiac failure unresponsive to medical therapy. Progressive macrocephaly. Seizures. Developmental delay. Reversible neurological deficit. • AIM— TO REDUCE THE AMOUNT OF AV SHUNT.• Arterial approach ---Permanent embolic agent---

NBCA glue, Onyx.• Transvenous route tried.

NBCA glue embolisation of vein of galen Aneurysmal Malformation

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CEREBRAL VENOUS SINUS THROMBOSIS Intravenous anticoagulation — most cases

are successful Local thrombolysis

INDICATIONS: Presentation in coma. Clinical deterioration despite full anticoagulation. Treatment modalities 1) Pharmacological thrombolysis of the cerebral

venous sinuses is usually performed via the Transvenous femoral route in an anaesthetised patient.

2)Pharmaco-mechanical thrombolysis may also be achieved using a microcatheter,microwire or microsnare.

Local pharmacomechanical thrombolysis in superior sagittal sinus (SSS) thrombosis.

. 3)Mechanical— Saline jet vacuum device -- It consists of a double lumen

5 French catheter tapering to 3.5 French, high velocity saline jets, exiting the catheter at a pressure of 2500 psi, are directed through one lumen, connected to a bag of heparinised saline. A venturi effect breaks up the thrombus and the debris is directed down the other lumen and collected in a bag.

Saline jet vacuum device

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Examples of mechanical measures to remove clot. A, low pressure angioplasty, B clot disruption with theNeurojet (Possis) and c. clot retrieval with the Merci

device.

AngioJet catheter treatment -dural sinus thrombosis

IDIOPATHIC INTRACRANIAL HYPERTENSION

• remains a diagnosis of exclusion ( Friedman D., Jacobson D.: Neurology 59, 2002)

• To clarify the relation of IIH to associate narrowing of lateral dural sinuses

• The neuro interventional community is still debating and strives to justify neurovascular strategies for treatment.

--Causes• Focal narrowing in the transverse sinuses unilateral or

bilaterally.• Secondary to raised central venous pressure .

IDIOPATHIC INTRACRANIAL HYPERTENSION • Investigation :MRI, MRV

• Catheter angiography with retrograde venography

• Pull-back manometry

• Focus of interest of venous manometry: a) gradients across the irregularities of lateral sinus b) gradients at confluence of sinuses/jugular bulb

Intervention---Stenting• General anaesthesia is required for stent deployment

because the dura and sinuses are sensitive to pain. Stenting is achieved directly through a percutaneous jugular venous puncture. A guide catheter is manipulated into the transverse sinus and a self expanding stent deployed across the stenosis .

Optic papilla protrusion

Endovasal manometry: lft

Compliant balloon angioplasty of lateral sinus

Initial Gd MRI Follow up 6 we Gd MRI

VASCULAR INTERVENTIONS OF TUMOURS

SKULL BASE TUMOURS

Common tumours requiring preopreative embolisation are

• Meningiomas.• Angiofibromas.• Glomus tumours . Objective selective obliteration of arterial feeder before surgical

resection. • Delivered under sedation by trans femoral route by selective

catheterisation of the vascular pedicle. • Aim to occlude the pre capillary arteriole.

• Embolic agent —PVA(150-250 microns).

If intra tumoural shunts are present -- Particle size increase. Slurry of PVA and AVitene. Small coil or silk sutures. Liquid coils.Embolisation should be performed 24–72 hours before surgery

to allow progressive thrombosis. • If very small size particle are used then skin necrosis and

cranial nerve palsy occur.

Polyvinyl alcohol (PVA) embolisation of a glomus jugulare tumour.

Glomus jugulare tumour

Meningioma

Inferior Petrosal sinus sampling

To obtain blood sample in pituitary microadenoma

Brain tumour chemotherapyPrinciple→Intra arterial infusion of chemotherapeutic

agents ↓ 1)increased concentration of c.t.agents

locally ↓ 2)increase cytotoxicity, Decreased side

effects.Procedure: Selective catheterization of the artery supplying the tumour done

under systemic heparinisationc.t. agents infused.

ChemoembolizationChemoembolization works to attack the tumour in two

ways. 1) Delivers a very high concentration of chemotherapy

directly into the tumor, without exposing the entire body to the effects of those drugs.

2) The procedure cuts off blood supply to the tumor, depriving it of oxygen and nutrients, and trapping the drugs at the tumor site to enable them to be more effective.

• Super selective catherisation of the vascular pedicle is done.

• Chemotherapeutic agents mixed with particulate embolic agents infused through the micro catheter.

Image guided percutaneous treatment

Direct percutaneous embolisation in vascular malformation of head and neck

Low flow malformation like haemangio-lymphangioma or venous malformation.

Under image guidance needle is placed percutaneously in the lesion

↓Contrast injected through the needle to delineate the

vascular compartment and venous drainage↓

Concentrated alcohol injected to the lesion.

Image guided photodynamic therapy Photodynamic therapy is a minimally invasive palliative treatment

for malignancy . Intra venous injection of photosensitizing drugs.

Image guided needles placed in the tumour

Fibre optic cables are placed through the needles,providing a foccused delivery of laser light.

Laser light + Photosensitising drugs Activates the drug Singlet oxygen(highly cytotoxic) Interacts with

Oxygen

CONCLUSION • Proper knowledge of vascular anatomy is very important .

Proper pre surgical ,clinical and radiological assessment helps in surgical planning and avoid catastrophy.

• There has been enormous growth and development in neuro endovascular expertise and technology in recent years, and this expansion continues allowing increasingly safe and more effective ways to treat many intracranial and extra cranial vascular lesions .

• It is necessary to provide the patient with all treatment options. Considering cost-effectiveness and that endovascular treatment has lower morbidity and mortality rates than does neurosurgery. It is crucial for the group to take a leading role in the future of neurointervention.

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