Spi Study Guide

Front 1

Ultrasound:
a) is a transverse wave
b) is a mechanical wave
c) is a longitudinal wave
d) have particles that move up and down.

Back 1

B & C

Front 2

Ultrasound can travel through a vacuum.
True/False

Back 2

False

Front 3

Ultrasound is created by:
a) a transducer
b) the vibration of a moving object
c) the medium
d) pressure

Back 3

B

Front 4

As sound propagates there are variations in quantities called _______ _________.

Back 4

Acoustic variables

Front 5

Which one of these is not an acoustic variable?
a) pressure
b) partical motion (distance)
c) parameters
d) density
e) temperature

Back 5

C

Front 6

Longitudinal wave particles move perpendicular to the direction of the wave.
True/False

Back 6

False. They move in the same direction.

Front 7

Transverse wave particles move in the same direction to the direction of the wave.
True/False

Back 7

False. They move perpendicular to the direction of the wave.

Front 8

All of the following are true of sound waves EXCEPT:
a) they are acoustic
b) they are pressure waves
c) they are transverse
d) they move energy

Back 8

C

Front 9

Which of the following best describes sound waves?
a) a series of compressions and rarefactions
b) waves that are heard by man
c) movement of molecules and energy to one location to another.
d) waves that are used to make images of anatomy.

Back 9

A

Front 10

Which of the following best describes sound waves?
a) transverse, pressure waves
b) transverse, longitudinal waves
c) longitudinal, out-of-phase waves
d) longitudinal, pressure waves

Back 10

D

Front 11

Two waves are traveling in a medium and arrive at a location at the same time. What event takes place?
a) constructive interference
b) destructive interference
c) interference
d) reflection

Back 11

C

Front 12

Which types of waves will exhibit both constructive and destructive interference?
a) waves of different amplitude
b) a pair of longitudinal waves
c) waves of different frequency
d) out of phase waves.

Back 12

C

Front 13

Sound waves travel through areas of low density and high density. Areas of low density is referred to as ______________

Back 13

Rarefactions

Front 14

Sound waves travel through areas of low density and high density. Areas of high density is referred to as ______________

Back 14

Compressions

Front 15

Match the following frequency with it's proper sound wave:
1) Audible Sound
2) Infrasound
3) Ultrasound
4) Diagnostic Imaging
a) >20 Hz
b) >20,000 Hz (20 kHz)
c) 20- 20,0000 Hz
d) 2-12 MHz (1-15 MHz)

Back 15

1) c... 20-20,000 Hz
2) a....<20 Hz
3) b....>20,000 Hz (20 kHz)
4) d....2-12 MHz (1-15 MHz)

Front 16

The time to complete1 cycle (the time from the start of a cycle to the start of the next cycle.
a) period
b) frequency
c) wavelength
d) amplitude

Back 16

A

Front 17

Units for period:
a) mm, m, cm
b) s, ms, us
c) Hz, KHz, MHz

Back 17

B. Units of time.

Front 18

What are the typical values for period?
a) 0.2-0.7 s
b) 2.0- 3.5 us
c) 0.1-0.5 us
d) 0.05- 0.5 ms

Back 18

C

Front 19

Period is determined by the sound source. It cannot be changed by the sonographer.
True/False

Back 19

True

Front 20

The number of cycles of an acoustic variable (pressure, particle motion (distance), density, and temperature) that occur in one second.
a) period
b) frequency
c) PRP
c) PRF

Back 20

B

Front 21

Unit of measure for frequency:
a) MHz
b) Hz
c) kHz

Back 21

B

Front 22

Frequency is determined by the:
a) medium only
b) medium & sound source
c) sound source only

Back 22

C

Front 23

Frequency cannot be changed by the sonographer as long as the same transducer is being used.
True/False

Back 23

True

Front 24

In clinical imaging, frequency ranges are:
a) 2.5-10 MHz
b) 3- 16 MHz
c) 2.3 - 14 MHz
d) 2-12 MHz

Back 24

D

Front 25

Frequency affects:
a) attenuation & lateral resolution
b) penetration & axial resolution
c) propagation speed & period

Back 25

B

Front 26

What is the relationship between period and frequency?
a) they are inversely related
b) they are reciprocals
c) they are directly proportional
d) they are unrelated

Back 26

B.....this means they are opposites. When one increases, the other decreases.
P x f = 1
P = 1/f
f = 1/P

Front 27

The distance that one complete cycle occupies...the LENGTH of the cycle.
a) period
b) frequency
c) wavelength
d) amplitude

Back 27

C

Front 28

Wavelength is determined by:
a) Sound source
b) sonographer
c) medium
d) propagation speed

Back 28

A & C

Front 29

In clinical imaging, wavelength ranges from:
a) 0.25 - 0.6 mm
b) 0.25 - 0.6 us
c) 0.15 - 0.8 mm
d) 0.15 - 0.8 s

Back 29

C

Front 30

Wavelength can be changed by the sonographer while using the same transducer.
True/False

Back 30

False

Front 31

How is frequency related to wavelength?
a) inversely
b) unrelated
c) directly proportional
d) they are reciprocals

Back 31

A

Front 32

High frequency transducers have a long wavelength.
True/False

Back 32

False. f and wavelength are inversely related so is f is high wavelength is short.

Front 33

Lower f transducers have a longer wavelength.
True/False

Back 33

True. f and wavelength are INVERSELY related, so if f is low wavelength is long.

Front 34

Wavelength is the only parameter that is determined by both the sound source and the medium.
True/False

Back 34

True

Front 35

The speed at which sound travels through a medium or the distance that a sound wave travels through a medium in 1 second.
a) Pulse Repetition Period
b) wavelength
c) propagation speed
d) amplitude

Back 35

C

Front 36

Propagation speed is determined by:
a) the sound source only
b) the medium only
c) the sound source and the medium
d) time

Back 36

B

Front 37

propagation speed (c) units of measure:
a) s, ms, us
b) cycles/second
c) m/s, mm/us (distance/time)
d) all of the above

Back 37

C

Front 38

Propagation speed in soft tissue:
a) 1540 m/s, 1.54 mm/us, 1.54 km/s
b) 1540 mm/us, 1.54 m/s, 1.54 km/s
c) 1540 km/s, 1.54 m/s, 1.54 mm/us

Back 38

A..This is approximately 1 mile per second.

Front 39

_______ & _______ determines the propagation speed of the medium.

Back 39

Stiffness and Density

Front 40

If stiffness increases propagation speed decreases?
True/False

Back 40

False. Think about bone. If stiffness increases, c increases.

Front 41

If density increases with no change in the stiffness, then c will decrease.
True/False

Back 41

True.

Front 42

Wave Equation

Back 42

lambda=c/f

Front 43

What is NOT a property of ultrasound waves?
a) Amplitude
b) Distance
c) Power
d) Intensity

Back 43

B

Front 44

Medium 1 has a density of 9 and a stiffness of 6.
Medium 2 has a density of 8 and a stiffness of 6.
In which medium will sound travel slower?

Back 44

medium 1....since both media have the same stiffness, the medium with the greater density has the lower propagation speed.

Front 45

Relates to the strength and magnitude of a sound wave.
a) amplitude
b) power
c) intensity
d) pressure

Back 45

A

Front 46

Amplitude is the difference between the ____ value and the ____ value of an acoustic variable.

Back 46

average value & maximum value

Front 47

Amplitude can have units of any of the acoustic variables. Match the acoustic variables with it's unit of measure.
a) pressure
b) density
c) particle motion
d) temperature
1) cm, inches, any distance
2) pascals
3) degrees
4) g/cm^3

Back 47

a) pressure - 2) pascals
b) density - 4) g/cm^3
c) particle motion - 1) any distance
d) temperature - 3) degrees

Front 48

In clinical imaging, pressure amplitude ranges from 1 million pascals (1 MPa) to 3 million pascals (3 MPa).
True/False

Back 48

True

Front 49

INITIALLY, the amplitude is determined only by the:
a) medium
b) sound source
c) medium and sound source

Back 49

B

Front 50

Amplitude increases/decreases as sound propagates through the body.

Back 50

decreases

Front 51

The rate at which the amplitude decreases as sound propagates depends on the characteristics of:
a) the medium only
b) the sound source only
c) both the sound wave and the medium
d) the medium and the sound source.

Back 51

C

Front 52

Can the sonographer alter the initial amplitude?

Back 52

Yes

Front 53

With CW, the positive and negative amplitudes are:
a) equal
b) different
c) inversely related
d) proportional

Back 53

A

Front 54

With PW, the positive and negative amplitudes are often:
a) equal
b) different
c) inversely related
d) proportional

Back 54

B

Front 55

What is the difference between amplitude and peak-to-peak amplitude?
a) amplitude is measured from the baseline of the maximum to the baseline of the minimum.
b) the difference between maximum and minimum values of an acoustic variable.

Back 55

A

Front 56

What MUST occur within a wave for it to move?
a) power
b) intensity
c) pressure
d) energy

Back 56

C

Front 57

Waves will go through areas of compression and rarefactions, which indicate areas of high and low pressure.
True/False

Back 57

True

Front 58

Relates to the strength of a sound wave:
a) pressure
b) intensity
c) amplitude
d) power

Back 58

D

Front 59

Rate at which work is performed or energy is transferred from the entire sound beam.
a) pressure
b) intensity
c) amplitude
d) power

Back 59

D

Front 60

Power can be controlled by the sonographer.
True/False

Back 60

True

Front 61

Power is determined initially by the
a) sound source
b) medium
c) sound source and the medium

Back 61

A

Front 62

Power decreases as sound propagates through the body.
True/False

Back 62

True

Front 63

The rate at which sound propagates depends on the characteristics of what?
a) the medium and the wave
b) the density of the medium
c) the sound source

Back 63

A

Front 64

How are amplitude and power related?
a) they are inversely related
b) they are proportional
c) they are unrelated

Back 64

B

Front 65

Power is proportional to amplitude squared.
True/False

Back 65

True

Front 66

If amplitude is tripled, what happens to power?

Back 66

it is tripled

Front 67

If amplitude is halved, what happens to power?

Back 67

it is halved.

Front 68

Related to the strength and concentration of energy in the sound beam.
a) power
b) pressure
c) intensity
d) temperature

Back 68

C

Front 69

Intensity equation

Back 69

intensity (W/cm^2) = power (w)/ area^2

Front 70

Can intensity be controlled by the sonographer?

Back 70

yes

Front 71

Clinical imaging ranges for intensity:
a) 0.03-400 W/cm^2
b) 0.01-300 W/cm^2
c) 2.4-250 W/cm^2
d) 0.023-200 W/cm^2

Back 71

B

Front 72

How is intensity related to both power and amplitude?
a) inversely
b) directly
c) unrelated

Back 72

B

Front 73

When power or amplitude of a beam increases, what happens to intensity?

Back 73

It is increased as well

Front 74

How is intensity related to power?
a) inversely
b) proportional
c) unrelated

Back 74

proportional

Front 75

How is intensity related to amplitude?

Back 75

Intensity=amplitude^2

Front 76

When discussing relationships between amplitude, power, and intensity, the word __________ ALWAYS follows the word amplitude.
a) cubed
b) squared
c) range

Back 76

B
Power is related to amplitude squared.
Intensity is related to amplitude squared.
Power in related to the intensity.

Front 77

A unit used to express a relative difference between 2 acoustic signals.
a) Hz
b) MHz
c) dB

Back 77

C

Front 78

What is the wavelength of 3Mhz sound in soft tissue?
a) 0.51 m
b) 0.51 km
c) 0.51 mm
d) 0.51 um

Back 78

C
In soft tissue, wavelength is 1.54mm divided by the f in MHz. Thus 3 MHz sound will have a wavelength of 0.51 mm.

Front 79

What is the wavelength of a wave with an unknown f traveling in soft tissue?
a) 0.51 us
b) 0.51 m/s
c) 0.51 pascals
d) 0.51 watts
e) 0.51 mm

Back 79

E is the only answer with units of distance. Therefore, it is the best answer. Choice A has units of time, b has units of speed, C has units of pressure, and D has units of power.

Front 80

Which of the following is an acoustic variable? (Could be more than one)
a) frequency
b) density
c) particle motion
d) temperature
e) period
f) pressure

Back 80

B, C, D & F

Front 81

The effects of tissue on sound waves are called _______ ______ ________.

Back 81

Acoustic propagation properties

Front 82

The effects of a medium on an u/s wave are called ________ ______ ____.

Back 82

Acoustic propagation properties.

Front 83

How are the following parameters related - directly, inversely, or unrelated?
f & period
amplitude and power
amplitude and intensity
wavelength and intensity
wavelength and f
c & density
elasticity and c
c & compressibility
stiffness & c
f & c
f & intensity
power & f

Back 83

f & period......inversely
amplitude and power......directly
amplitude and intensity....directly
power and intensity....directly
wavelength and intensity...unrelated
wavelength and f....inversely
c & density....inversely
elasticity and c.....inversely
c & compressibility....inversely
stiffness & c.....directly
f & c....unrelated
f & intensity.....unrelated
power & f....unrelated

Front 84

Another word for stiffness

Back 84

bulk modulus

Front 85

What is usually the dominant factor that determines c?
a) the medium
b)stiffness
c) density
d) the sound source

Back 85

B

Front 86

Harder media have a higher c.
True/False

Back 86

True

Front 87

List these media in order of their propagation speeds from lowest to highest:
solids, gases, liquids

Back 87

gases
liquids
solids

Front 88

What happens when propagating sound energy strikes a boundary between 2 media and some returns to the transducer?
a) reflection
b) refraction
c) scattering
d) absorption

Back 88

A

Front 89

The acoustic resistance to sound traveling through a medium.
a) reflection
b) refraction
c) acoustic impedance
d) scattering
e) absorption

Back 89

C

Front 90

Acoustic impedance equation

Back 90

Z= density (p) (kg/m^3) x c (m/s)