Module 5: Echo Doppler Basics Flashcards
What does doppler echo include? 2
- Colour flow imaging (Tissue doppler TDI)
- Spectral doppler
What is three types of spectral doppler?
- Pulsed wave
- Continuous wave doppler
- Tissue doppler
What do we use doppler in echo to assess? 5
- Flow through valves
- Pulmonary venous flow into the LA
- Hepatic venous flow
- SVC/IVC flow
- Aortic flow
differentiate tissue from blood
What are normal vs Abnormal valve velocities?
What is valvular stenosis?
A narrowing of the valve resulting in increased flow velocities
When does valvular stenosis occur?
Occurs during forward or antegrade flow through a valve
What is valvular regurgitation?
Valvular regurgitation occurs when a valve cannot coapt, or close correctly resulting in leakage, or backward flow through the valve
What timeframe does valvular regurgitation occur?
During the timeframe the valve should normally be closed
What is the three things to look out for in doppler echo?
- Colour
- Pulsed wave spectral
- Continuous wave spectral
What information does doppler provide for echo?
- Qualitative info
- Gives us a good idea about regurgitation, stenosis, etc
What information does pulsed wave spectral tells us about doppler echo? 2
- Quantitive
- Gives us a spectral signal from a specific sample spot
What does continuous wave spectral tells us about doppler echo? 3
- Quantitive
- Gives us a spectral signal from a entire line of scan
- Used for very high velocities
What is the order of images for echo?
- 2D/Mmode (+/- zoom)
- Colour
- Spectral (either PW or CW)
Colour doppler is a pulsed wave technique and subject to what?
Aliasing
When aliased the flow direction is what?
Ambiguous
The LVOT and AV colour doppler here is what?
Aliased in the normal heart
Normal flow direction depends on what?
The cardiac cycle
What does the cardiac cycle add to cardiac component?
Dynamic component
Colour doppler is what kind of technique?
Pulsed wave doppler technique with many tiny sample volumes placed in the colour box
With Colour doppler being a PW doppler technique what does this subject it to? 2
The same rules as Pulsed way such as
1. Lowering frame rate
2. The Nyquist limit
Color aliasing can be a helpful artifact in echo to do what?
Accessing valve pathology
What are some advantages of colour doppler? 3
- Sensitivity
- Region of interest
- Laminar vs turbulent flow
How is sensitivity good for colour doppler?
It can detect small amounts of blood flow
How does region of interest help colour doppler?
Anatomical + hemodynamics information on one image
Why is seeing laminar vs turbulent flow good for Colour doppler?
We are able to see the difference because turbulent flow in the heart is almost always aliased
What is the disadvantages of Colour doppler? 2
- Aliasing
- Directional Ambiguity
What is directional ambiguity in terms of colour doppler? 2
- Perpendicular flow appears as multiple colours
- Confuses the interpretation of blood flow direction
When does aliasing happen in colour doppler?
At high velocities
What are some questions we need to ask to find out if the Colour is normal for colour doppler? 2
- Know when to expect regurgitation on the valve you are assessing
- Know which color regurgitation will appear on the valve you’re assessing
For colour doppler what will stenosis show?
Aliasing
During colour doppler what will regurgitation show?
A bit of aliasing right at the valve, unless the leak is really big
What are the steps for adjusting gain for colour doppler?
- Turn gain up until you see speckle
- Turn gain down just until the speckle disappear
Colour gains should be adjusted when?
Must be adjusted for each new patient or when scale has been majorly adjusted
What happens when you overgain?
Bleeding
What happens when you undergain?
Missing data
What are some tips for adjusting scale for colour images?
Assess flow type
1. average velocity
2. High Velocity
3. Low Velocity
What should the scale be set for average velocity?
Leave scale as in (50-75)