Where does the CCA bifurcate?

at the level of the

superior thyroid cartilage

What is the first branch of the subclavian artery?

vertebral

What does systemic system on each side of the neck imply?

waveform should be the same on each side.

What is the function of the extracranial cerebrovascular system function?

Supply blood flow to

cerebral hemispheres

eyes

face muscles

forehead

scalp

Where does the vertebrals supply blood to?

• Brain stem
• Cerebellum
• Undersurface of the cerebral hemispheres

Where does the carotid artery supply blood to?

• Eyes
• Anterior 2/3 of brain

Name the branches of the aortic arch

• Right Innominate/Brachiocephalic
  • Right CCA
  • Right Subclavian artery
• Left CCA
• Left Subclavian artery

Where does the ECA supply blood to?

face

neck

scalp

Name the branches of the ECA.

• Superior thyroid
• Ascending pharyngeal
• Lingual
• Facial
• Occipital
• Posterior auricular
• Superficial temporal
• Maxillary

Name the 4 divisions of the ICA.

• Cervical
• Petrous
• Cavernous
• Cerebral

Explain the location of the ICA compared to the ECA.

posterior and lateral

What type of flow is expected in the bulb of the carotid?

turbulent

What is the flow of the vertebral arteries?

Posterior circulation

• 1st branch of the SCA
• Pass cranially through the fossae of the transverse processes of the upper 6 cervical vertebrae
• Enters the skull through the foramen magnum, joins contralateral vertebral
• Together they form the Basilar artery (intracranially)

What do the two vertebrals form?

Basilar artery

What is the diameter of the CCA?

5-6 mm

What is the diameter of the ICA?

4-5 mm

What is the diameter of the ECA?

3-4 mm

What is the diameter of the vertebral artery?

2-3 mm

How much of the carotid's blood enters the brain via the ICA?

80%

How much of the carotid's blood supplies the face and neck via the ECA?

20%

Explain the waveform of the CCA

Mimics both ICA and ECA waveforms

Explain the waveform of the ICA

low resistant - constant forward flow

Forward flow throughout the cardiac cycle

Explain the waveform of the ECA

high resistant

steep forward stroke

Forward flow during systole, low or reverse diastolic component

Explain the waveform of the vertebral artery

low resistant

What is resistance determined by?

diastole

less diastole = high resistance

What causes tortuous vessels?

can be born this way

can happen over time as people age they shrink

*elevation can result but state that vessel was tortuous

Which is the left CCA?

right

On what side is the notch in long?

superior

On what side is the notch in transverse?

patient right

Where is the notch when imaging the right cerebrovascular system in transverse,

posterior

When imaging the left cerebrovascular system in transverse, where will the notch be?

anterior

How should plaque be measured?

transverse measurement

lumen vs true lumen

Why is plaque measured in transverse?

Longitudinal estimation of stenosis from B-mode image is usually unreliable, use transverse image.

*This minor plaque can be made to appear more or less stenotic in longitudinal view

Plaque Morphology

How do you tell the difference between the ICA and ECA?

• Anatomy
  • posterior position of ICA
  • branches of ECA
  • ICA size: not reliable when diseased

• Doppler waveforms & sounds
  • ICA = low resistance
  • ECA = high resistance

ICA lies _________ in the neck (95%)

ICA lies posterior in the neck (95%)

ECA position, whether lateral, anterior or medial, is _________.

ECA position, whether lateral, anterior or medial, is variable

What are the four sets of the ECA branches?

Anterior

Posterior

Ascending

terminal

What are the anterior branches of the ECA?

• Superior Thyroid
• Lingual
• External Maxillary (facial)

What are the posterior branches of the ECA?

• Occipital
• Posterior Auricular

What are the ascending branches of the ECA?

Ascending Pharyngeal

What are the terminal branches of the ECA?

• Superficial Temporal
• Internal Maxillary

What is Plaque?

Atherosclerotic material that builds up on the walls of arteries

• It restricts flow
• It can break loose

What is a lumen?

The flow space within a vessel

What is residual lumen?

amount of flow space after accounting for the plaque

What is a Bifurcation?

The point of vessel division

• can be a common site of stenosis

What are Collateral Circulation?

• Alternate pathways for blood flow that become functional after obstruction.
• Detours

What is an Embolus?

An object traveling through the circulation that can cause occlusion

What are the different types of an Embolus?

air

tumor

fat

bullets

foam

clot

What is hemodynamics?

blood flow characteristics

What is the Doppler angle?

The angle of the Doppler beam with respect to the angle of blood flow

Angle of Incidence

Angle theta q

What is the best Doppler angle?

0 ^o

What is the Optimal Doppler angle?

45^o to 60^o

What is the worst Doppler angle?

90^o

Explain angle correct?

Visually adding a correction factor to the Doppler angle so that correct velocities can be calculated

What is Spectral Analysis?

• Plotting of returned Doppler signals
• frequency shifts on the vertical axis
• amplitude on the “Z” axis
• Time on the horizontal axis

Explain velocity?

• The speed of blood
• Calculated from Doppler frequency shift & Doppler angle
• velocity is proportional to frequency shift
• Expressed as cm or m / second

Where is peak systole?

The highest point on the wave form

Where is end diastole?

The point just prior to the systolic upstroke

Beam Steering

Depth penetration may be improved by _____________________ .

Depth penetration may be improved by not steering the Doppler

Where is the waveform?

ICA

Where is the waveform?

CCA

Where is the waveform?

ECA

Where is the waveform?

vertebral

Where is the waveform?

subclavian

Hypoechoic / Anechoic

Dark or black areas on the image caused by objects with little or no reflectivity

Echodense/ Echogenic

Bright areas on the image caused by highly reflective material

Distal / Proximal Limits

The farthest and closest region that can be visualized

Plaque

A swollen area of the lining of an artery formed by the deposition of lipids

Calcific Plaque

Bright echogenic plaque which creates shadowing

Dense Plaque

Bright echogenic plaque which does not produce shadowing

Soft / Fibrous Plaque or Thrombus

Plaque which produces echoes (not hypoechoic) but not as bright as dense or calcific plaque

Intimal thickening or Fatty streak

Plaque that is along the wall of the vessel as a minimal amount

What is minimal degree of plaque?

10%

What is moderate degree of plaque?

60%

What is severe degree of plaque?

90%

What is Circumferential plaque?

Plaque along the entire lumen - all the way around

What is extensive plaque?

Plaque along a lengthy segment of the artery

What is scattered plaque?

Plaque found at several locations which are not connected

True Lumen

True Lumen is the original internal diameter of the vessel

Residual Lumen

Residual Lumen is the current internal diameter of the vessel

• What’s left over after the plaque has taken over; where the blood flow is flowing

Homogenous plaque

less likely to ulcerate

• Uniform in echo texture

Heterogeneous plaque

more likely to ulcerate

• Nonuniform in echotexture

Smooth vs Irregular plaque

• Talking about the surface of the plaque and it’s probability of ulcerating

Ulcerative Plaque

A scooped out appearance

shelf like projections

Occlusion

Complete blockage

• Best used with the terms probable & total
• Complete filling of the vessel internal area with heterogeneous material
• No blood flow

What must one do in calling an occlusion

sensitize the equipment before doing so

Decrease PRF

Increase color gain, use power Doppler

laminar flow

Orderly

non-turbulent

Sharp flow

Indicating a swift upstroke

Sharp peaks

Damped flow

Slow upstroke

Rounded Peaks

Monophasic

One upstroke within one cardiac cycle

Multiphasic

Multiple upstrokes within one cardiac cycle

Which is monophasic?

Antegrade

Flow in the direction that is expected from that specific vessel

Retrograde

Flow that is reversed from the expected direction for that vessel

Characterization of flow disturbances

Turbulence

Spectral Broadening

Disturbed flow

Window Filling

Gross Turbulence

Aliasing

A Spectral Doppler Artifact of Pulsed Doppler systems

Spectral Doppler displays the peaks wrapped in the reverse direction

Color Doppler displays as a reversed color

Mosaic

A mottled appearance caused by turbulent flow

Jet

A localized area of higher flow through and after an area high grade stenosis

Diploplia

double vision

Drop attack

falling to the ground without other symptoms

Syncope

transient loss of consciousness

Bruits

abnormal flow sounds caused by turbulent patterns

Subclavian steal

abnormal flow direction into the subclavian from the vertebral artery caused by stenosis of the subclavian

• Subclavian artery has a severe stenosis or occlusion
• Vertebral artery must compensate for the reduction of flow
• Becomes a collateral pathway to the extremity
• RETROGRADE flow or abnormal flow present in the vertebral arter

What side does subclavian steal syndrome usually occur?

left

Amaurosis fugax

temporary partial or total blindness

Homonymous hemianopia

Blindness in the outer half of the visual field

Vertigo

difficulty in maintaining equilibrium

movement that is not real

Ataxia

inability to control gait or touch an article

Paresis

weakness or slight paralysis on one side of the body

Paresthesia

numbness or lack of feeling

Dysphasia

impaired speech

Aphasia

inability to speak

What is a Carotid body tumor?

A small mass of vascular tissue that adjoins the carotid sinus. It functions as a chemoreceptor sensitive to changes in oxygen tension of the blood and signals necessary changes in respiratory activity

Nonatherosclerotic lesions

Trauma

Fibromuscular Dysplasia (FMD)

• dysplasia of the media with overgrowth of collagen
• beadlike appearance on angiography
• Seen in young women

Collagen vascular connective tissue disorders

Where does a Nonatherosclerotic lesions usually occur?

mid to distal

renal or carotid

What are the Mechanisms of disease?

• Stenosis
• Embolism
• Thrombosis
• Aneurysm
• Nonatherosclerotic lesions
• Carotid body tumor

What are the Risk Factors &
contributing diseases?

• Diabetes mellitus
• Hypertension
• Smoking
• Hyperlipidemia

What is a Cerebrovascular Accident (CVA)?

Produces a permanent neurological deficit

What is an acute CVA?

symptoms of sudden onset

unstable

What is a Stroke in evolution?

symptoms come and go

unstable

What is a Completed stroke?

No progression or resolution of the symptoms

stable

What are the symptoms of Vertebrobasilar Insufficiency?

• Bilateral symptoms
• Visual blurring
• Paresthesia
• Vertigo
• Ataxia
• Drop attacks

What is a Reversible Ischemic Neurologic Deficit (RIND)?

• Lasts longer than a TIA
• Deficits resolve in time

What is a TIA?

Transient Ischemic Attack - TIA

A fleeting neurological dysfunction without lasting effects

What are the symptoms of a TIA?

last minutes - hours

never more than 24 hours

sensory, motor, speech impairment, monocular visual disturbance

What is the Etiology of a TIA?

heart or carotid artery emboli

What is NASCET?

North American Symptomatic Carotid Endarterectomy Trial

What is ECET?

European Carotid Endarterectomy Trial (ECET)

What is ACAS?

Asymptomatic Carotid Atherosclerosis Trial (ACAS)

What was the endpoint for all 3 Carotid Endarterectomy Trials?

Reduction of hemispheric stroke & death

In the Carotid Endarterectomy Trials what showed long term benefits?

surgery in pt’s with >60 – 70% stenosis

for both symptomatic & asymptomatic over medical treatment

What are the key points of spectral broadening?

• Spectral broadening is proportional to stenosis
• Filled spectral window suggests >50% diameter
• >70% stenosis has poor spectral border, high amplitude and low frequency
• Spectral broadening may be the only sign of stenosis

What can we expect from post stenotic flow?

turbulent – nonlaminar

• Although objective measurements have been created - - clinically spectral broadening is graded subjectively

What Factors cause abnormal Low PSV?

• Collateralization
• Low BP
• Decreased cardiac output

What Factors cause abnormal High PSV?

Hypertension

Why do we calculate Systolic Velocity Ratio?

• Physiological factors can change the absolute systolic velocities
• By comparing the CCA to the ICA we remove the Physiological factors affect.

Why do we take the End Diastolic Velocity?

• It becomes valuable in high grade stenosis
• Will not show change below 50% stenosis

When does the PSV drop off?

Stenosis starts to exceed Approximately 90 %

What affects the PSV

length of the stenosis

• A range of velocities are possible with variable stenosis - - - Precise velocity stenosis is not possible

What are the Cardinal Doppler Parameters?

Peak Systole

End Diastole

ICA/CCA Ratio

• Critical that measurements are taken at the highest velocity

Explain the velocity increase in a stenosis.

The amount of velocity increase is small until the stenosis exceeds 50%

What is velocity proportional to?

Velocity will be proportional to the amount of stenosis.

By measuring the velocity we measure the stenosis

In vascular what is everything weighed by?

Everything that we do in Vascular is weighed by the velocity more so than the Bmode measurement

What happens when no cause of asymmetry can be found?

other modalities should be used to find the cause.

Major asymmetry between right & left should be a red flag

If the CCA is normal what do we say about the waveform?

Should be low resistance

If the Distal CCA is obstructed what happens to the waveform?

High resistance

ECA waveform

If the proximal CCA is obstructed what happens to the waveform?

Dampened Waveform

• Best method of quantification is

What is the best method of Best method of quantification of the CCA

comparison with the contralateral side

CCA Pulsatility

• Normally the Pre-stenotic Area
• Stenosis can also occur at the CCA origin
• CCA waveforms may appear pre-stenotic or post stenotic

What are the three critical areas?

• Prestenotic Area
• Stenotic Area
• Post Stenotic Area