Neuroradiology%20presents

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Neuroradiology presents.
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Neurovascular Anatomy Cases
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Objectives

• Neurovascular imaging modalities
• Review of cerebrovascular anatomy
• Representative cases

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Neurovascular imaging

• Invasive
• - Digital Subtraction Angiography (DSA)
• Non-Invasive
• Ultrasound
• Carotid ultrasound
• CTA
• MRA
• Time of flight / Phase contrast
• Contrast-enhanced MRA

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Egas Moniz - 1934
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Direct Puncture
Carotid
Vertebral
Lateral
Lateral
AP
AP
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Sven Seldinger - 1953
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Digital Subtraction Angiography (DSA)

• Advantages
• Gold standard
• Best detail
• 3D angiography
• Arterial/Capillary/Venous phases
• Planning intervention
• Disadvantages
• Time consuming
• Invasive
• Low risk of vessel injury, stroke

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Risks of Angiography

• Stroke - 11000
• Contrast reaction - 11,000,000
• Groin hematoma - 1500
• Vasovagal reactions, etc.

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Aortic arch
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Normal Anatomy -DSA
Lateral Neck
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Carotid bifurcation
AP
Lateral
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Normal Anatomy - Carotid
AP
Lateral
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Phases of angiogramArterial Capillary Venous
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Middle cerebral artery
Diagnostic Cerebral Angiography, Osborn
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Lenticulostriates
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Anterior cerebral artery
Diagnostic Cerebral Angiography, Osborn
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Vertebral artery
Diagnostic Cerebral Angiography, Osborn
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Posterior circulation
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Posterior circulation
AP
Lateral
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3D-CRA
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Vascular territories
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Neurovascular imaging

• Non-Invasive
• Ultrasound
• Carotid ultrasound
• Transcranial doppler
• CTA
• MRA
• Time of flight / Phase contrast
• Contrast-enhanced MRA

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Duplex Carotid Ultrasound (DUS)
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Carotid ultrasoundBilateral severe ICA stenoses
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CT angiography

• Advantages
• Readily accessible
• Fast image acquisition
• Good detail
• Reconstructions (Ax/Cor/Sag)
• Disadvantages
• Radiation
• Contrast nephropathy
• Contrast allergy
• Calcification
• Metal artifact e.g. clip, coil, stent

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CT Angiography - CTA
Circle of Willis
Carotid bifurcation
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MR angiography

• Advantages
• No radiation
• TOF does not require contrast
• Other sequences DWI, GRE, FLAIR etc.
• Disadvantages
• Not as readily accessible
• Longer image acquisition time
• Patient motion
• Slow flow or turbulence
• Metal artifact
• Nephrogenic systemic fibrosis (Gadolinium )

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Aortic arch
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MR Angiography - MRA
Circle of Willis
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External carotid artery
Lateral
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Collateral circulation

• Primary
• Circle of Willis
• Fetal variants
• Secondary
• Extra- to intracranial connections
• e.g. ophthalmic to carotid
• Leptomeningeal collaterals

John Hunter, 1728-93
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Thomas Willis 1648
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Circle of Willis
Ant. communicating artery
A1
Post. communicating artery
P1
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Cerebral venous system
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AP
Lateral
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Stroke
Normal
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Focal lucency Loss of G/W Mass effect
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6 hrs
Loss of BG Loss of insular ribbon
24hrs
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2hrs
Hyperdense Middle Cerebral Artery Sign HMCAS
24 hrs
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ASPECTS Alberta Stroke Program Early CT Score
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ASPECTS

• Normal 10
• Score lt 7 risk of bleed after TPA is 14x higher
• Score lt 7 predicts poor functional outcome

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DWI MRI
Not all acute infarcts are MCA!
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DWI
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Acute Infarcts

• CT - screening, by 3-6 hrs
• MRI, Diffusion-weighted imaging (DWI) is within
  1hr, confirmatory
• CT, CTA with CT perfusion
• MR, MRA with MR perfusion

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Hemorrhagic transformation
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Carotid Atherosclerosis

• Accounts for at least 50 of strokes
• NASCET - 1991
• Endarterectomy (CEA) prevents strokes

Severe stenosis
Normal
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North American Symptomatic Endarterectomy Trial
NASCET
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KFC
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Near- occlusion
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Complete occlusion
Thrombus
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John Hunter (1728-1793)
Blood goes where it is needed
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Right ICA occlusion
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Collateral supply to the brain
Circle of Willis
EC-IC
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Duplex Ultrasound
Best screening modality
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DUS and CTA - Good enough for surgery
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MRA of carotid disease
Good enough for surgery
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Carotid Angioplasty/Stenting (CAS)
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Pre-
Post-
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CAS Techniques

• Major concern distal emboli

? Value of EPDs
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Carotid Angioplasty and Stenting (CAS)

• NASCET
• Healthy scepticism

The Hype Curve
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Endarterectomy or stenting?

• Trials in progress
• CREST (North America), recruitment of 2500 pts
  completed, results expected in spring 2010
• ICSS (Europe/Australia)

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Intracranial Disease
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Endovascular Therapy for Acute Stroke
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Left MCA Occlusion
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Intra-arterial TPA
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Basilar artery occlusion
Pre-
Post-
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5K
17 K start-up, 2-3K per case
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Endovascular Stroke Therapy

• Time is brain - 2 million neurons/min.
• Re-perfusion does not always correlate with good
  clinical outcome
• IV r-TPA within 3 hrs most practical
• IA - large vessel occlusions (MCA or basilar), up
  to 6 hrs
• Still no conclusive evidence favouring IA or IV

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Venous infarcts
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Dural venous sinus thrombosis
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Cerebral Aneurysms
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Common locations of aneurysms
NEJM 2006 355928
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P.comm
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A. comm
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R MCA
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Aneurysm clipping
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Endovascular Therapy of Cerebral Aneurysms
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CT head
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Right carotid arteriogram
Lateral
AP
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Oblique projection
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Post coil embolization20 GDC coils
AP
Lateral
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Oblique projection
Before
After
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Clip or coil?
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Clip or coil? Factors to consider

• Rupture status
• Morphology
• Location
• Age
• Comorbidities / Other

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Clip or coil? Ruptured aneurysms

• ISAT trial
• Multi-centre randomized trial of clipping (1070)
  vs. coiling (1073) for patients with ruptured
  intracranial aneurysms
• Aneurysms were all deemed suitable for either
  coiling or clipping (Only 22 of aneurysms!)
• Outcome mRS 3-6 at 1 year
• 6.9 ARR in favor of coiling
• (NNT 14.5)

Lancet 2002360126774
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Clip or coil? Unruptured aneurysms

• What are the indications for treatment?
• Risk of rupture vs. risk of treatment
• ISUIA trial

Lancet 200336210310
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Clip or coil? Unruptured aneurysms

• Treatment - Clip or coil?
• No trial comparing clipping/coiling for
  unruptured aneurysms
• Upcoming RCTs
• ISUIA IV (Conservative vs. surgery or
  endovascular)
• TEAM (Conservative vs. endovascular)

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Clip or coil? Morphology

• Neck / Base
• Unfavorable factors for simple coiling
• Neck gt 4 mm
• Fundusneck ratio close to 11

Neurosurgery 2000461397-1407
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Balloon-assisted coiling
Neurosurgery 199741975-978
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Stent-assisted coiling
NEJM 2006355928-939
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Stents and Coils
lateral
AP
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Covered Stent
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Cerebral Arteriovenous Malformations (AVMs)
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MRI brain Axial T2
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MRA Time of flight
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Right ICA arteriogram
Lateral
AP
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Left vertebral arteriogram
Lateral
AP
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Cerebral AVM

• Abnormal collection of blood vessels where
  arterial blood flows directly into draining veins
  without interposed capillary bed
• Clinical presentation
• Asymptomatic
• Hemorrhage (65)
• 2-4/yr
• 10 first year after hemorrhage
• Seizures (15-35)
• Headache (15)
• Progressive neuro deficits
• Pulsatile bruits

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Treatment of brain AVMs

• Observation
• Surgical resection
• Stereotactic radiosurgery
• lt3 cm
• Takes 1-2 years
• Endovascular embolization
• Pre-operative or pre-radiosurgery
• n-BCA (glue) or Onyx

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Endovascular Therapy of Brain AVMs
NBCA
crazy glue
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Onyx embolization x2
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Post embo
ICA
VA
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Post surgical resection
ICA
VA
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What to do?

• Nothing
• Radiation
• Embolization
• Embo Surgery
• Surgery
• ARUBA

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Treatment of AVMs

• ? Natural history of unruptured/ruptured AVMs
• Risk of bleed or disability lt 2/yr?
• Risks of Embolization - up to 20
• Risks of Embo Surgery up to 58
• ARUBA Trial - A Randomized Trial of Unruptured
  Brain AVMs

Hartman et al. Stroke 2005 36 2431-35
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• 48 yr. old male
• MVA 2 months previously
• Gradual onset L proptosis, chemosis, bruit
• Sudden onset leg weakness, dysarthria

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Traumatic (Direct) Carotid Cavernous Fistula

• MVC
• Within a few weeks
• Proptosis, chemosis, bruit, CN palsy
• transarterial
• Balloon/coil occlusion
• transvenous

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3 months
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The End
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External Carotid Artery
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External Carotid Artery - Lat
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External Carotid Artery - AP
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Epistaxis
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Juvenile Nasal Angiofibroma
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Tumours
Carotid body tumour
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Chemodectomas

• Carotid body tumour
• Glomus Vagale
• Glomus jugulare
• Glomus tympanicum

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Meningioma
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Mother - in - Law
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