Extra-cranial Duplex US Examination Flashcards
Transient Ischemic Attacks dont last longer than?
24 hours
What are the four symptoms typically associated with carotid artery atherosclerosis?
- TIA - mini stroke that doesn’t last longer than 24 hours
- Reversible ischemic neurologic deficit (RIND) - symptoms are the same as a TIA but last between 24-72 hours
- Amaurosis Fugax - temporary painless loss of vision in one or both eyes
- Stroke
What should your scale be set to in a carotid exam?
20-40 cm/s
What artery are you “tapping” in the temporal tap to determine if you are imaging the ECA?
Superficial temporal artery
What portion of what vessel is important in patients at risk for fibromuscular dysplasia?
Distal ICA
What gland can be seen superficial to the distal ICA?
SMG
What type of waveform is seen in the vertebral artery?
Low resistance as it supplies blood to the brain and eyes
From the carotid artery, what transducer movement would be used to image the subclavian artery?
Inferior
What type of waveform is seen in the subclavian artery?
High resistance as it supplies muscle and not the brain
Arterial velocity measurements should be obtained using an angle of insonation of what range of degrees?
45-60 degrees
Where in the carotid arteries does plaque generally form?
- Carotid bifurcation in the distal CCA
- Proximal ICA
- Proximal ECA
What abnormality is described as separation of the vessel layers?
Arterial dissection - creates a false lumen in which blood from the true lumen can flow
What type of waveform shows a higher forward diastolic flow velocity?
Low resistance
What type of waveform shows a lower diastolic flow velocity?
High resistance
What percentage of blood from the CCA flows through the ICA?
70%
Where are baroreceptors located in the carotid system?
Proximal ICA - helps control blood pressure
What adjustment should be considered when imaging the vertebral arteries after the carotid?
Decrease the scale for slower flow
What type of waveform is seen in the brachiocephalic artery?
High resistance flow - triphasic waveform
In what arteries will may have severe stenosis in subclavian steal?
- L subclavian
- R brachiocephalic
What kind of subclavian steal shows antegrade flow with a deep notch before systole?
Hesitant or latent - Stage 1
What kind of subclavian steal has “to-and-fro” flow?
Bidirectional or alternating - Stage 2
What kind of subclavian steal has fully retrograde flow?
Complete - Stage 3
What type of colour doppler flow is seen that precedes a complete occlusion?
“String sign” or “trickle flow”
Where are you most likely to see the “string sign” on colour doppler?
ICA
A severe distal CCA obstruction with continued patency of the carotid bifurcation is often referred to what?
A choke lesion - flow may be reversed in the ECA to supply the ICA
Doppler waveform with a ICA stenosis vs ICA occlusion? (hint: what may also be seen in the CCA)
ICA stenosis - CCA will also appear blunted and resistive
ICA occlusion - CCA takes on features of patent ECA
Where does stenosis of the vertebral artery generally occur?
Origin of the vessel from the subclavian artery
What may be going on with the heart if the waveform appears dampened and has delayed acceleration if there is no stenosis?
Low cardiac output or poor EF
In what cardiac consideration will you see with “pulsus bisferiens”? (when waveform has two prominent systolic peaks separated by a mid-systolic retraction)
Aortic valvular disease or hypertrophic cardiomyopathy
What is the ratio used to classify disease of the ICA?
ICA (highest PSV from stenosis) /CCA (PSV in normal mid to distal segment)
If there is significant stenosis in the origin of the CCA, what will the waveform be like in the distal CCA?
Dampened
What would the velocity have to be in order to classify a CCA or ECA stenosis as a 50-99% stenosis?
200cm/s or greater
How do we quantify a vertebral artery stenosis of 50% or greater?
V1 - maximum PSV in proximal vertebral artery / V2 - PSV from normal distal vertebral artery
Symptoms of a TIA occur on what side of the body in relation to the affected carotid artery causing the symptoms?
Opposite side of the body from the TIA
Symptoms of amaurosis fugax occurs on what side of the body in relation to the affected carotid artery?
The SAME side
What transducer movement would you use to go from the CCA to the vertebral arteries?
Slide or angle the transducer posteriorly
What transducer movement would you use to image the subclavian artery from the neck?
Angle inferiorly from the neck
T or F? Direct intervention is not possible with a completely occluded ICA?
TRUE
Doppler parameters are relatively inaccurate for subcategorizing stenoses of less than what percent in terms of diameter reduction?
50%
T or F? ICA/CCA ratio is valid in the presence of any type of CCA disease?
FALSE: is not valid when disease is significant
How do we identify a vertebral artery stenosis of 50% or greater?
- Use V1 - pre-stenosis (max velocity)
Use V2 - at stenosis (normal distal vertebral artery)
Use V1/V2 ratio. Will be >2.2 if stenosis is present
- A vertebral artery PSV of 150cm/s or greater
What PSV in the vertebral artery is indicative of stenosis?
150cm/s or greater
