Lecture 5: Carotid Artery Duplex Imaging Flashcards by Jenelle Nuqui

patient history that can indicate a carotid artery scan? (6)

neurological symptoms
myocardial infarction
HTN
diabetes
smoking
vascular surgeries

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3 scanning positions when scanning carotid

anterolateral
lateral
posterolateral

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the CCA waveform has elements of both ___ & ___

ICA & ECA

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what is interpretive criteria for carotid stenosis primarily based on?

velocities taken with PW Doppler waveform & waveform analysis

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this vessel is low resistance, has continuous forward flow, and no branches in the cervical region

ICA

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this vessel is high resistance, contains branches in the cervical portion, and responds to the temporal tap

ECA

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at the posterolateral approach, which branch of the CCA is in the near field and which is in the far field?

ICA is in the near field; ECA in far field

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this waveform has elements of both ICA & ECA with a sharp upstroke, moderate diastolic flow, and a well-defined dicrotic notch

CCA waveform

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the waveform of this branch of the carotid is low resistance with broad systolic peaks, substantial diastolic flow, and a dicrotic notch that isn’t well visualized

ICA waveform

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what is the typical range for PSV for the ICA?

54-88 cm/sec

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what is considered the abnormal PSV for the ICA?

> 100cm/sec
MAX FOR NL <125cm/sec

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the waveform for this branch of the CCA is high resistance with a sharp systolic upstroke, little flow in diastole, and a well-visualized dicrotic notch

ECA waveform

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what is the normal range for PSV in the ECA?

77-115 cm/sec
MAX FOR NL <125cm/sec

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how does plaque formation start?

lipids start infiltrating the tunica intima

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progressive accumulation of plaque affects which layers of the arterial walls?

initially affects intima; later intima & media

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what 3 types of deposits can be found with progressive build up of plaque?

fibrotic material
hemorrhagic products
calcifications

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how does fibrotic material in plaque show up on ultrasound?

hyperechoic but without shadowing

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how do hemorrhagic products in plaque show up on ultrasound?

depends on age of the blood

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how do calcifications in plaque show up on ultrasound?

hyperechoic with shadowing

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which type of plaque presents with more risk: smooth or irregular?

irregular

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another name for irregular plaque?

ulcerated plaque

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why is there an increased risk for ulcerated plaque?

there is an increased chance of rupture & erosion of intima

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what happens if there is an erosion of the intima?

it can break off and be swept away into the brain, leading to a stroke

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which type of plaque echogenicity is less cellular in content?

low level echogenicity

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what risk does low level echogenic plaque pose?

there's an increased risk for ulceration with cerebral ischemic symptoms

which type of plaque echogenicity contains fibrous plaque with collagen?

medium level echogenicity

medium level plaque echogenicity poses less risk for cerebral ischemic symptoms if plaque is ____

homogenous

why does high level echogenic plaque pose less risk for cerebral ischemic symptoms?

plaque is calcified and attached very well to the arterial wall

a normal spectral waveform has a ___ range of velocities in systole & diastole

narrow

a normal spectral waveform has an ___ spectral window

open

PSV of normal spectral waveforms are ___

< 125 cm/sec

what is the percentage of diameter reduction for a hemodynamically significant stenosis?

50-60% diameter reduction

a ___ diameter reduction correlates with __ area reduction

50% DR; 75% AR

what happens to PSV & EDV when there is a 50-60% DR?

both increase

the pre-stenotic area is considered the area distal to stenosis. T/F?

false; it's the area proximal to stenosis

is PSV of a pre-stenotic area normal or abnormal?

normal

at the stenotic site, what happens to PSV & EDV?

both velocities increase

spectral broadening doesn't occur at the stenotic site. T/F?

false; it does occur

what happens to PSV & EDV at the post-stenotic site?

both velocities decrease

what type of flow can you expect to see at the post-stenotic site?

turbulent

what 3 factors influence carotid velocities?

1. cardiac output 2. blood pressure 3. obstruction in contralateral CCA

what is cardiac output?

the amount of blood the left ventricle is ejecting per minute

how do you calculate the diameter reduction of a stenosis?

go in transverse DR % = (residual lumen/original lumen)(100)

6 categories of stenotic disease?

1. normal 2. mild 3. moderate 4. moderately severe 5. severe 6. totally occluded

PSV of a normal carotid?

< 125 cm/sec

what % is considered mild stenosis?

1-15%

PSV, EDV, and sonic window of mild stenosis?

PSV <125 cm/sec EDV slightly increased sonic window open

what % is considered moderate stenosis?

16-49%

PSV and sonic window of moderate stenosis?

PSV <125 cm/sec sonic window may or may not be open

what is normal ICA/CCA ratio?

< 1.5

ICA/CCA ratio of moderate stenosis?

normal <1.5

what % is considered moderately severe stenosis?

49-80%

PSV of moderately severe stenosis?

> 125 cm/sec

EDV of moderately severe stenosis?

increase but < 105 cm/sec

sonic window of moderately severe stenosis?

spectral broadening & window filling

ICA/CCA ratio of moderately severe stenosis?

2.0+

what % is considered severe stenosis?

80-99%

PSV of severe stenosis?

80% stenosis = 250+ cm/sec 99% stenosis = 400 cm/sec

EDV of severe stensois?

> 110 cm/sec

ICA/CCA ratio of severe stenosis?

5.6+

how should you adjust PRF to look for trickle flow/string sign in severe stenosis?

lower PRF/scale to increase sensitivity

how should you adjust wall filter to look for string sign in severe stenosis?

lower wall filter

how should you adjust doppler gain to look for trickle flow in severe stenosis?

increase doppler gain

how should you adjust sample size to look for trickle flow in severe stenosis?

increase sample size

where should you image in ICA to prove flow with severe stenosis?

go as distal as possible

use ___ doppler to search for trickle flow in severe stenosis

power doppler

how can systole & diastole appear in the CCA with total occlusion?

systole is shorter with rounded peak diastole has no flow

the CCA waveform with severe proximal stenosis will have a ___ systolic component

dampened

the CCA waveform with severe proximal stenosis will have ___ flow in diastole

forward

the CCA waveform with severe proximal stenosis will have ___ pulsatility

decreased

the CCA waveform with severe distal stenosis will have a ___ systolic portion

blunted

the CCA waveform with severe distal stenosis will have a ___ diastole

absent or decreased