Lesson 11 Flashcards
What does the reflection between 2 different boundaries depend on?
Media impedance
What is the result of a large difference between impedances?
A large reflection
What would happen if you injected air into a liver?
You would get a large reflection
- air vs solid
What are 2 examples of contrast agents?
- Levovist
2. SonoVue
What are 4 characteristics of contrast agents?
- Easy administration
- Nontoxic
- Stable
- Small enough to perfuse through blood vessels (capillaries)
What do most contrast agents contain?
Microbubbles of air
What stabilizes contrast agents? (3)
- Protein
- Lipid
- Polymer shell
What are contrast agents?
Dye that get injected to be bale to make structures more visible
How do reflections from blood show up as?
Weak echoes
- increases with contrast agents
What will high IRC show up as on an ultrasound?
As bright echoes
What do contrast agents produce?
Strong harmonics
When are harmonics produced?
When sound is produced non-linearly
What will introduction of contrast agents do with tissues?
Increase the echogenicity
- normally makes the tissue brighter and lesion darker, but can sometimes be the other way around
What is another use of contrast agents?
Perfusion rate
What can the ultrasound do at higher amplitudes to the bubbles?
Pop them
