Ultrasound

Question 1

Frequency of linear vs. phased array probe

Answer 1

Linear probe (f 5-15 Hz) vs. cardiac/phased-array probe/lower-frequency probe (1-5 Hz)

Question 2

Define artifact

Answer 2

Artifact- image not representing a structure but due to phenomenon of sound waves

Do not persist on multiple plans

Question 3

What kind of artifact is an A-line?

Answer 3

A-line = reverberation artifact

-hyperechoic strucure (large delta in acoustic impedance btwn pleural space)

Question 4

What is time-gain compensation?

Answer 4

Machine automatically increases gain as you go deeper b/c the soundwaves take a longer time to get back to the probe so signal gets weakened/attenuated

Farther structures would be too hypoechoic (less white) without this

Question 5

What is the focal zone?

Answer 5

Focal zone = narrowest portion of the sound beam where the best lateral resolution is available

Best focus

Question 6

In color doppler which color is towards vs. away

Answer 6

Red = towards probe

Blue = away from probe/transducer