Week 5 - Lesson 2 (Part 2) Flashcards
What is the normal grey scale characteristics of the carotid arteries? (6)
- Smooth vessel walls
- No appreciable plaque in lumen
- Intimal-media layer is clearly visible
- Uniform throughout the length of the vessel
- Lumen is anechoic
- Occasional reverberation artifacts in lumen attributed to adjacent internal jugular vein
What are abnormalities that can be picked up in the grey scale of the carotid arteries? (3)
- Plaque
- Intraluminal defects
- Iatrogenic injury
Iatrogenic
Nicked/added injury (man made) to a vessel
What is the sonographers role when assessing the carotid arteries? (3)
- Assessing lumen for presence of wall thickening and plaque
- Measuring the AP wall thickness if abnormal
- Follow the protocol for carotid artery duplex exam in the department where you work
What do you do if there is a noticeable area of plaque anywhere in the system?
Run the doppler sample carefully throughout the potential stenosis
What are the 4 levels you document the doppler flow at a stenosis?
- Proximal to it
- assess flow change - Within it
- at highest attainable velocity
- take 3 different samples to find the highest one - Distal to it
- to detect post stenotic turbulence - Further downstream for tardus parvus waveform
What do you measure for grading purposes of a stenosis? (2)
- PSV on all vessels
2. EDV in the ICA stenosis
What are extra images to take for a stenosis? (2)
- Vertebral artery flow and direction with triplex doppler
- if there is reversal of flow in the vertebral artery, then the ipsilateral SCA must be assessed for stenosis/occlusion - ECA flow at the PSV
What is the waveform of a normal CCA?
Biphasic
- combination of ECA and ICA
What kind of diastole happens in the CCA?
A longer one
What kind of waveform happens at the proximal CCA of a stenosis?
Biphasic
- start to lose some of the end diastolic
What does a mid CCA of a stenosis look like sonographically? (4)
- Greater peaks
- gets sharp tall and fast
- first thing that gets affected - Higher velocities
- High diastolic flow
- severe (low for mild) - High pitch sound
What kind of waveform happens at the distal CCA of a stenosis?
Monophasic
What does a distal CCA of a stenosis look like sonographically? (4)
- Lose peaks
- blunted - Dampened waveform
- Slow flow
- Tardus parvus signalling
What will you see just distal to the stenosis of the CCA?
PST
- post stenotic turbulence
- they will have shattered peaks and spectral broadening
What waveform should the subclavian artery be?
Triphasic
What kind of resistance should the subclavian artery be?
High resistance
What does it mean if the subclavian artery flow absent, turbulent, damped or monophasic?
A disease may be present
What should be assessed if you can visualize a high level stenosis or occlusion in the subclavian artery?
Vertebral arteries
- looking carefully for the presence of an subclavian steal syndrome
Subclavian steal syndrome
Is a constellation of signs and symptoms that arise from retrograde (reversed) blood flow in the vertebral artery or in the internal thoracic artery, due to a proximal stenosis and/or occlusion of the subclavian artery
Where is retrograde present on spectral doppler?
Below the baseline
- away
Where is antigrade present on spectral doppler?
Above the baseline
- towards
What is normal flow dependent on? (2)
- Age
2. Cardiac output
What is the normal flow for the subclavian artery?
140 cm/s
What is the normal flow for the common carotid artery?
80-100 cm/s
What is the normal flow for the internal carotid artery?
< 125 cm/s
What is the normal flow for the external carotid artery?
120 cm/s
What is the normal flow for the vertebral artery?
20-60 cm/s
What kind or resistance and pulsatility occurs in the SCA? (2)
- Resistance = high
2. Pulsatility = high
What kind or resistance and pulsatility occurs in the CCA? (2)
- Resistance = mix of ECA and ICA
2. Pulsatility = medium
What kind or resistance and pulsatility occurs in the ICA? (2)
- Resistance = low
2. Pulsatility = low
What kind or resistance and pulsatility occurs in the ECA? (2)
- Resistance = high
2. Pulsatility = high
What kind or resistance and pulsatility occurs in the vertebral? (2)
- Resistance = low
2. Pulsatility = low