Techniques in Noninvasive Vascular Diagnosis: Vascular 1 Flashcards

at the level of the

superior thyroid cartilage

vertebral

waveform should be the same on each side.

Supply blood flow to

cerebral hemispheres

eyes

face muscles

forehead

scalp

• Brain stem
• Cerebellum
• Undersurface of the cerebral hemispheres

• Eyes
• Anterior 2/3 of brain

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

face

neck

scalp

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

• Cervical
• Petrous
• Cavernous
• Cerebral

posterior and lateral

turbulent

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)

Basilar artery

5-6 mm

4-5 mm

3-4 mm

2-3 mm

80%

20%

Mimics both ICA and ECA waveforms

low resistant - constant forward flow

Forward flow throughout the cardiac cycle

high resistant

steep forward stroke

Forward flow during systole, low or reverse diastolic component

low resistant

diastole

less diastole = high resistance

can be born this way

can happen over time as people age they shrink

*elevation can result but state that vessel was tortuous

right

superior

patient right

posterior

anterior

transverse measurement

lumen vs true lumen

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

• 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 posterior in the neck (95%)

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

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Anterior

Posterior

Ascending

terminal

• Superior Thyroid
• Lingual
• External Maxillary (facial)

• Occipital
• Posterior Auricular

Ascending Pharyngeal

• Superficial Temporal
• Internal Maxillary

Atherosclerotic material that builds up on the walls of arteries

• It restricts flow
• It can break loose

The flow space within a vessel

amount of flow space after accounting for the plaque

The point of vessel division

• can be a common site of stenosis

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

An object traveling through the circulation that can cause occlusion

air

tumor

fat

bullets

foam

clot

blood flow characteristics

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

Angle of Incidence

Angle theta q

0 ^o

45^o to 60^o

90^o

...

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

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

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

The highest point on the wave form

The point just prior to the systolic upstroke

Depth penetration may be improved by not steering the Doppler

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ICA

CCA

ECA

vertebral

subclavian

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

Bright areas on the image caused by highly reflective material

The farthest and closest region that can be visualized

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

Bright echogenic plaque which creates shadowing

Bright echogenic plaque which does not produce shadowing

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

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

10%

60%

90%

Plaque along the entire lumen - all the way around

Plaque along a lengthy segment of the artery

Plaque found at several locations which are not connected

True Lumen is the original internal diameter of the vessel

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

less likely to ulcerate

• Uniform in echo texture

more likely to ulcerate

• Nonuniform in echotexture

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

A scooped out appearance

shelf like projections

Complete blockage

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

sensitize the equipment before doing so

Decrease PRF

Increase color gain, use power Doppler

Orderly

non-turbulent

Indicating a swift upstroke

Sharp peaks

Slow upstroke

Rounded Peaks

One upstroke within one cardiac cycle

Multiple upstrokes within one cardiac cycle

Flow in the direction that is expected from that specific vessel

Flow that is reversed from the expected direction for that vessel

Turbulence

Spectral Broadening

Disturbed flow

Window Filling

Gross Turbulence

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

A mottled appearance caused by turbulent flow

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

double vision

falling to the ground without other symptoms

transient loss of consciousness

abnormal flow sounds caused by turbulent patterns

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

left

temporary partial or total blindness

Blindness in the outer half of the visual field

difficulty in maintaining equilibrium

movement that is not real

inability to control gait or touch an article

weakness or slight paralysis on one side of the body

numbness or lack of feeling

impaired speech

inability to speak

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

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

mid to distal

renal or carotid

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

• Diabetes mellitus
• Hypertension
• Smoking
• Hyperlipidemia

Produces a permanent neurological deficit

symptoms of sudden onset

unstable

symptoms come and go

unstable

No progression or resolution of the symptoms

stable

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

• Lasts longer than a TIA
• Deficits resolve in time

Transient Ischemic Attack - TIA

A fleeting neurological dysfunction without lasting effects

last minutes - hours

never more than 24 hours

sensory, motor, speech impairment, monocular visual disturbance

heart or carotid artery emboli

North American Symptomatic Carotid Endarterectomy Trial

European Carotid Endarterectomy Trial (ECET)

Asymptomatic Carotid Atherosclerosis Trial (ACAS)

Reduction of hemispheric stroke & death

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

for both symptomatic & asymptomatic over medical treatment

• 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

turbulent – nonlaminar

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

• Collateralization
• Low BP
• Decreased cardiac output

Hypertension

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

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

Stenosis starts to exceed Approximately 90 %

length of the stenosis

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

Peak Systole

End Diastole

ICA/CCA Ratio

• Critical that measurements are taken at the highest velocity

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

Velocity will be proportional to the amount of stenosis.

By measuring the velocity we measure the stenosis

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

other modalities should be used to find the cause.

Major asymmetry between right & left should be a red flag

Should be low resistance

High resistance

ECA waveform

Dampened Waveform

• Best method of quantification is

comparison with the contralateral side

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

• Prestenotic Area
• Stenotic Area
• Post Stenotic Area