Lesson 23 (Part 3) Flashcards
What will a good sonographer do?
They will analyze the spectral display in conjunction with the colour and grayscale information to assess for normal blood flow and pathology
What signals do arteries have? (2)
- They are pulsatile
2. They have higher velocity waveforms
What signals do arteries have? (2)
- They are phasic
2. Lower velocity waveforms
What do we asses when analyzing waveforms? (4)
- Arterial vs Venous Signals
- High vs Low resistance flow
- Areas of stenosis
- Pre (proximal)/post (distal) stenosis waveforms
What is being looked at in resistance flow? (2)
- Systolic portions
2. Diastolic portions
What does high resistance show? (5)
- ECA, extremities
- Quick upstroke
- Low diastole
- Negative flow
- below the baseline - More echoic
What does low resistance show? (7)
- ICA/CCA, blood hungry organs (liver, renals, etc.)
- Vasodilation
- Slow upstroke
- Higher diastole
- Positive flow
- above the baseline - Appears more faint
- No reversal flow
Where is an example where you would see low resistance?
The brain
What is the formula for the continuity rule?
Q = V ave x A
What happens to area in areas of stenosis?
It decreases
- gets more narrow
What happens to velocity in areas of stenosis?
It increases
- higher pressure
Turbulence
Surpassing Reynolds number
Stenosis
High velocities relative to stenosis (potential for aliasing)
What does stenosis have a potential for?
Aliasing
What is spectral broadening related to?
Turbulence
Spectral broadening
Wider range of spectra
What does spectral broadening allow? (2)
- More “variety” of shifts
2. Narrowing of windows
What is the most obvious reason for spectral broadening?
Stenosis
- but can also be that you are a bad sonographer
What errors that can be conducted in spectral broadening? (2)
- Increase gain
- too much - Increase sample volume size
- catching multiple vessels at once
What can tortuous vessels give you?
Larger variety of signals
What are downstream clues?
Increased resistance
- looks like an ECA
What are upstream clues?
- Tardus Parvus waveform
2. Monophasic waveform
What does upstream clues suggest?
Proximal stenosis
What does downstream clues suggest?
Possible distal stenosis
