LEC 15 - Abdominal US Flashcards
What are the disadvantages to abdominal US?
Nonspecific
Bone or air - can’t tell the difference
What are the advantages to abdominal US?
Soft tissue - great clarity
Quick
Inexpensive
Convenient
What is the importance of coupling?
Squeeze all the air out
US beam can’t penetrate with air present
What are three coupling media options?
Gel
Isopropyl alcohol
Water
What are the characteristics of gel media?
Water-based
Slow to couple
Long duration
What are the characteristics of isopropyl alcohol?
Fast to couple
Short duration
Why doesn’t water work as a media?
Rolls right off the skin due to natural fat that is present
When is it important to only use isopropyl alcohol?
When taking a needle aspirate
What is the importance of frequency?
increasing frequency, decreases penetration, but increases resolution
Term: Reflection
Sound hits something changes speed gives an echo back this is necessary to see color
Otherwise everything is black
What are the three components that can cause reflection?
Density
Velocity
Rigidity
When is a fluid not dark in color?
When there is a high cell count
What are the two directions of resolution?
Pulse duration
– and –
Line density
What direction is line density?
Horizontal
What direction is pulse duration?
Vertical
Why is a steering probe really good for chest?
It can get between the ribs
What are the three categories of artifacts?
White + Black + Double image
What are the two types of white artifacts?
Distal enhancement
– and –
Reverberation
What type of white artifact makes a useable image?
Distal enhancement
What are the types of black artifacts?
Shadowing
– and –
Refraction
What is the structure that causes refraction?
Curved border
What is the structure that causes shadowing?
Luminal object
What is distal enhancement?
Transmission through medium with no attenuation
What structures cause distal enhancement?
Cystic structure
Cysts
Gall bladder
What is reverberation?
Signal goes from muscle to air to muscle again
the extreme difference causes white lines
Where is reverberation normal?
lugns
What causes ringing in the lungs?
Mild defects in the lungs
What is an important diagnostic of shadowing?
Bladder stones
