Chapter 1

Question 1

What is acoustic pressure?

Answer 1

Quantification of strength of a wave

Question 2

What is acoustic pressure measured in?

Answer 2

Pascals

Question 3

Do longer or shorter pulses tend to have bigger frequency spectrums?

Answer 3

Shorter pulses

Question 4

What is period?

Answer 4

The inverse of frequency

Question 5

What determines the speed of sound in a medium?

Answer 5

The materials density and compressibility (stiffness)
- sound travels slower in a more dense and more compressible material

Question 6

What is acoustic impedance?

Answer 6

The property of a tissue that influences the strength/amplitude of reflected echoes

Question 7

What is the symbol for acoustic impedance?

Answer 7

Z

Question 8

What is the equation for acoustic impedance?

Answer 8

Z = pc
p = mediums density
c = speed of sound

Question 9

What are diffuse reflectors?

Answer 9

Rough edges that produce reflection of echoes in different directions - not perpendicular

Question 10

How do specular and scattered reflections differ?

Answer 10

Scattered echoes are weaker

Question 11

What are Rayleigh scatterers?

Answer 11

Scattering object, whose dimensions are &laquo_space;ultrasound wavelength (e.g. RBC)

Question 12

What are the two sources of attenuation?

Answer 12

1. Reflection and scatter at interfaces
2. Tissue absorption

Question 13

How does attenuation change with frequency?

Answer 13

Higher frequencies are attenuated more than low frequencies