Week 5 - Lesson 2 (Part 3) Flashcards
What does normal < 125 cm/s PSV mean?
Minimal or no spectral broadening
What does 1-15% - < 125 cm/s PSV mean?
Spectral broadening during deceleration phase of systole
What does 16-49% - < 125 cm/s PSV mean?
Spectral broadening throughout systole
What does 50-79% - < 125 cm/s PSV mean?
With end diastolic < 140cm/s and marked spectral broadening
What does 80-99% - < 125 cm/s PSV mean?
With end diastolic > 140 cm/s and marked spectral broadening
What does 100% - < 125 cm/s PSV mean?
Occlusion
- no signal
- blockage
What does end diastole do?
Bumps the stenosis from mild to severe/critical
Spectral broadening
Is the window beneath the waveform that is partially or completely filled in
- seen in varying degrees of stenosis
- also can be man made by us not being careful with doppler gain
What kind of diastolic flow does the ECA have?
Relatively little diastolic flow
What kind of diastolic flow does the ICA have?
Relatively high diastolic flow
What kind of characteristic flow does the CCA have?
Usually has both ECA and ICA flow pattern characteristics
Where is the highest velocity in the vessel?
In the centre of the lumen
Where is the lowest velocity in the vessel?
By the walls
Where is low resistance flow? (4)
- Brain
- ICA
- Kidneys
- Liver
What kind of resistant flow is forward flow in systole?
High
- above the baseline
- first stroke
What kind of resistant flow is diastole?
Low or reversed
- below the baseline
- second stroke
What kind of flow is late diastole?
Forward flow
- above the base line
- third stroke
Where is high resistance flow? (6)
- Face
- Scalp
- Muscles
- not during exercise - Eyes
- Arms
- Legs
What is the flow in the bulb like?
Disturbed
Why is the flow in the bulb disturbed flow?
Due to separation of flow as it enters the proximal ICA where it widens
How does flow in the bulb appear on spectral doppler?
Above and below the baseline
- this is normal
What does black indicate in the bulb on colour doppler?
It is the point of when it hinges from red to blue or blue to red
- no flow signal occurs here
What are factors affecting the ICA waveform? (8)
- Atheroma/plaque
- Tortuosity
- Aortic valve disease
- Aortic arch/innominate disease
- Distal carotid siphon disease
- Intracranial vessel disease
- Contralateral carotid occlusion
- High cardiac output states
What are problems and pitfalls with doppler? (6)
- Incorrect doppler sample volume (gate) position or size
- Doppler angle is too large
- > 60 degrees - Doppler settings are too high for low velocity
- Tortuous vessels
- High grade stenosis
- Calcified plaque
How do you correctly set up doppler? (4)
- Angle correct is at 60 degrees
- Located centrally within vessel and parallel to walls
- Colour flow box angled correctly
- Spectral waveform set correctly with baseline and velocity scale
What kind of sample gate do you want with a larger vessel?
Smaller sample gate
What kind of sample gate do you want with a smaller vessel?
Wider sample gate
- need to let more through because the vessel is already small
What can cause a stenosis?
Kinks in a vessel
- tortuous
How can you tell if you have an ICA occlusion? (3)
- ICA will have no colour flow
- Visible plaque at origin
- Hypoechoic lumen
Why do they only do surgery if the ICA is blocked, not the ECA?
It can cause a stoke because it supplies the brain
- ECA is just monitored
What happens once a vessel is occluded?
It cant be opened again, so other routes are put in place for blood flow
What are causes of pulsatile neck masses? (5)
- Normal but prominent carotid artery bulb
- Ectatic carotid,brachiocephalic or subclavian artery
- Aneurysm of carotid artery
- Carotid body tumour
- Enlarged lymph node adjacent to carotid sheath
Ectatic
Jagged road
- due to vessel wall damage
