Deck 2: Ultrasound

Question 1

Period is the ________ it takes for one ________ to occur.

A) time; cycle
B) time; wavelength
C) frequency; cycle
D) time; pulse

Answer 1

A
Period is the time that it takes for one cycle to occur.

Question 2

________ is the amount of complete cycles per second.

A) Wavelength
B) Period
C) Frequency
D) Propagation speed

Answer 2

C
Frequency is defined as the number of complete cycles per second.

Question 3

Ultrasound pulses contain a range of frequencies called the ________.

A) fundamental frequencies
B) duty factor
C) pulse repetition frequencies
D) bandwidth

Answer 3

D
Ultrasound pulses contain a range of frequencies called the bandwidth.

Question 4

Propagation speed is higher in ________ than in soft tissue.

A) lung
B) bone
C) water
D) fat

Question 5

Frequency ________ wavelength.

A) is directly proportional to
B) is inversely proportional to
C) is equal to
D) has no bearing on

Question 6

Pulsed ultrasound consists of ________ separated by ________ of time.

A) frequencies; cycles
B) pulses; cycles
C) pulses; gaps
D) cycles; pulses

Question 7

Propagation speed is primarily determined by the ________ of the medium.

A) density
B) thickness
C) stiffness
D) content

Question 8

Stiffer media have ________ sound speeds.

A) lower
B) higher
C) stiffness does not change the propagation speed
D) sound cannot propagate through stiffer media

Question 9

The fraction of time that pulsed ultrasound is on is called ________.

A) pulse repetition period
B) duty factor (DF)
C) period
D) spatial pulse length

Question 10

________ are the even and odd multiples of the fundamental frequency.

A) Bandwidths
B) Harmonics
C) Mechanical waves
D) Side lobes

Question 11

All of the following are acoustic variables except ________:

A) pressure
B) density
C) compression
D) particle vibration

Question 12

Pulse repetition frequency (PRF) refers to the ________ of pulses occurring in one second.

A) speed
B) number
C) type
D) cycle

Question 13

Wavelength is the _______ over which one cycle occurs.

A) time
B) length
C) area
D) power

Question 14

Regions of lower pressure and density are called ________.

A) compressions
B) rarefactions
C) longitudinal waves
D) acoustic variables

Question 15

The rate at which energy passes through a unit area is called ________.

A) amplitude
B) power
C) attenuation
D) intensity

Question 16

Doppler ultrasound pulses are typically ________ cycles long.

A) 2-3
B) 12-30
C) 5-20
D) 5-30

Question 17

If frequency increases,each cycle (period) ________.

A) increases
B) decreases
C) remains unchanged
D) doubles

Question 18

The following are all ultrasound frequencies except:

A) 30,000 Hz
B) 250 kHz
C) 15 kHz
D) 0.3 MHz

Question 19

Propagation speed is the speed at which a wave ________ through a medium.

A) cycles
B) refracts
C) travels
D) reflects

Question 20

Sound requires a ________ through which to travel.

A) medium
B) pressure
C) vacuum
D) wave

Question 21

The attenuation of a 5.0 MHz transducer at a depth of 4 cm is ________ dB.

A) 1.6
B) 10
C) 16
D) 20

Question 22

Calculate the pulse duration for a 3.0 MHz transducer in soft tissue with a four-cycle pulse.

A) 1.2 µs
B) 1.3 µs
C) 12 µs
D) 13 µs

Question 23

The velocity of sound in human soft tissue is assumed to be a constant.If you employ a 7.5 MHz transducer,what is the wavelength of the sound?

A) 0.11 mm
B) 0.20 mm
C) 0.025 mm
D) 1.1 mm

Question 24

If the beam area decreases,the intensity ________.

A) decreases
B) remains unchanged
C) increases
D) quadruples

Question 25

The average propagation speed in human soft tissue is ________.

A) 1.54 cm/µs
B) 1.54 mm/µs
C) 1.54 m/sec
D) none of the above

Question 26

For perpendicular incidence,the incidence angle is ________.

A) 50
B) 10
C) 90
D) 0

Question 27

If beam power increases,intensity ________.

A) increases
B) decreases
C) doubles
D) remains unchanged

Question 28

The wavelength of 3 MHz ultrasound in soft tissue is ________ mm.

A) 510
B) 5.1
C) 0.51
D) 4.6

Question 29

What is the attenuation of a 7.5 MHz transducer at a depth of 20 mm?

A) 7.5 dB
B) 5.0 dB
C) 0.53 dB
D) 75 dB

Question 30

As sound travels,the reduction in amplitude and intensity of the wave is called ________.

A) scattering
B) attenuation
C) absorption
D) reflection

Question 31

Attenuation increases with increasing ________.

A) wavelength
B) frequency
C) power
D) pressure

Question 32

What is the pulse duration of a four-cycle pulse in a period of 0.5 µs?

A) 0.2 µs
B) 2.0 µs
C) 1.25 µs
D) 0.125 µs

Question 33

What is the period of a 5.0 MHz transducer in soft tissue?

A) 0.2 µs
B) 0.02 µs
C) 3.1 µs
D) 0.2 sec

Question 34

If you switch to a lower frequency for penetration,the wavelength of the transducer ________.

A) remains unchanged
B) decreases
C) increases
D) doubles

Question 35

The pulse repetition frequency is the number of pulses that occur in a single ________.

A) microsecond
B) second
C) millisecond
D) pulse

Question 36

What is the attenuation coefficient for a 5.0 MHz transducer in soft tissue?

A) 0.25 dB/cm
B) 0.1 dB/cm
C) 2.5 dB/cm
D) 10 dB/cm

Question 37

What would be the frequency for a 0.22 mm wavelength in soft tissue?

A) 5.0 MHz
B) 7.0 MHz
C) 7.5 MHz
D) 3.5 MHz

Question 38

What is the spatial pulse length in soft tissue for a four-cycle pulse,using a frequency of 5.0 MHz?

A) 0.6 mm
B) 6.0 mm
C) 0.9 mm
D) 9.0 mm

Question 39

If the wavelength is 0.5 mm,the spatial pulse length for a 4 cycle pulse is ________.

A) 0.2 mm
B) 8.0 mm
C) 0.8 mm
D) 2.0 mm

Question 40

At what depth does a 3.0 MHz transducer have an attenuation of 9 dB?

A) 6.0 mm
B) 0.6 cm
C) 6.0 cm
D) 0.6 mm

Question 41

Attenuation encompasses ________.

A) absorption
B) scattering
C) reflection
D) all of the above

Question 42

In perpendicular incidence,what is the intensity reflection coefficient for impedances of 45 and 55 rayls?

A) 0.001
B) -0.01
C) 0.01
D) -0.001

Question 43

If the number of cycles in a pulse is reduced,the pulse duration ________.

A) is increased
B) is decreased
C) remains unchanged
D) is not possible

Question 44

If the impedances are equal between two media in perpendicular incidence,there is no ________.

A) reflection
B) transmission
C) angle of incidence
D) angle of transmission

Question 45

The proportion of intensity to amplitude is ________.

A) tripled
B) halved
C) squared
D) quadrupled

Question 46

The even harmonics of 2 MHz are ________ MHz.

A) 2, 4, 6
B) 4, 8, 12
C) 2, 4, 8
D) 4, 6, 8

Question 47

Lateral position errors occur on an image due to sound ________.

A) reflection
B) attenuation
C) refraction
D) transmission

Question 48

The distance to the reflector (D) in soft tissue with a round-trip time of 39 µs is _______.

A) 3 mm
B) 3 cm
C) 13 mm
D) 13 cm

Question 49

If the propagation speed through the second medium is greater than through the first medium,the transmission angle is ________.

A) less than the incidence angle
B) equal to the incidence angle
C) greater than the incidence angle
D) unrelated to the incidence angle

Question 50

What units are used to quantify attenuation?

A) Unitless.
B) dB/cm.
C) dB.
D) Rayls.

Question 51

The attenuation of a 5 MHz transducer in soft tissue would be ________ dB at 2 cm of depth.

A) 20
B) 5
C) 10
D) 1.25

Question 52

The unit for impedance is ________.

A) W/cm2
B) dB/cm
C) watt
D) rayl

Question 53

Duty factors for sonography are typically in the range of ________%.

A) 0.1-1.0
B) 0.5-2.0
C) 25-50
D) 90-100

Question 54

What does 3 dB of attenuation mean?

A) One half the original intensity.
B) One third the original intensity.
C) Three decibels more than the original intensity.
D) Increasing amplitude.

Question 55

Which of the following is not a term used to describe continuous wave ultrasound?

A) Pulse duration.
B) Frequency.
C) Wavelength.
D) Propagation speed.

Question 56

What is the spatial pulse length of a four-cycle pulse with a wavelength of 0.1 mm?

A) 4.0 mm
B) 0.4 cm
C) 0.4 mm
D) 40 mm

Question 57

The attenuation coefficient for soft tissue using a 10 MHz transducer is ________.

A) 5 dB/cm
B) 5 dB/mm
C) 10 dB/cm
D) 10 dB/mm

Question 58

Impedance is equal to density multiplied by ________.

A) propagation speed
B) wavelength
C) path length
D) stiffness

Question 59

Amplitude and intensity are indicators of the sound wave's ________.

A) strength
B) bandwidth
C) wavelength
D) duty factor

Question 60

Continuous wave (CW) Doppler has a duty factor of ________ %.

A) 1.0
B) 0.10
C) 100
D) 10

Question 61

The propagation speed for a round-trip time of 39 µs would be ________ mm.

A) 1540
B) 15.4
C) 1.45
D) none of the above

Question 62

________ is the dominant factor contributing to attenuation of ultrasound in soft tissue.

A) Absorption
B) Backscattering
C) Reflection
D) Range

Question 63

In oblique incidence,the ________ and ________ angles are always equal.

A) transmitted; reflected
B) normal; transmitted
C) incidence; reflection
D) incidence; transmitted

Question 64

The distance to a reflector in soft tissue is 15 cm.What is the round-trip time to this depth?

A) 19.5 µs
B) 195 µs
C) 1.15 µs
D) 11.5 µs

Question 65

Interfaces that scatter ultrasound energy are usually considered those that are equal to or smaller than the wavelength.

Question 66

Amplitude is the maximum variation that occurs in an acoustic ________.

A) frequency
B) medium
C) variable
D) propagation speed

Question 67

If intensity reflection coefficient increases,intensity transmission coefficient ________.

A) decreases
B) increases
C) remains unchanged
D) is equal to the intensity reflection coefficient

Question 68

Almost all ultrasound contrast agents contain ________.

A) iodine
B) barium
C) epinephrine
D) gas microbubbles

Question 69

If the pulse duration is 3 µs and the pulse repetition period is 350 µs,the duty factor would be ________ %.

A) 0.8
B) 8.0
C) 0.08
D) 1.16

Question 70

Optison and Imagent are names of ultrasound ________.

A) machines
B) transducers
C) coupling mediums
D) contrast agents

Question 71

In oblique incidence,when the propagation speeds on either side of the boundary are different,which incidence is most likely to occur?

A) Transmitted.
B) Refracted.
C) Reflected.
D) Attenuated.

Question 72

For each centimeter of distance,the pulse round-trip travel time is equal to ________.

A) 3 µs
B) 13 µs
C) 15 µs
D) 26 µs

Question 73

Intensity is equal to the power of a wave divided by the ________ over which the power is spread.

A) diameter
B) radius
C) area
D) width

Question 74

If an echo returns 104 µs after a pulse was emitted by a transducer,at what depth is the structure that produced the echo located?

A) 0.8 mm
B) 80 cm
C) 8.0 mm
D) 8.0 cm

Question 75

Which of the following determines how fast images are generated?

A) Pulse duration.
B) Duty factor.
C) Pulse repetition frequency.
D) Pulse repetition period.

Question 76

The liquid suspensions that have been developed can be injected into the circulation intravenously to increase ________.

A) wavelength
B) propagation speed
C) impedance
D) echogenicity

Question 77

Ultrasound systems use propagation speed to determine

A) intensity of the sound wave
B) amplitude of the sound wave
C) echo location of the display
D) attenuation of the sound wave

Question 78

The best way to describe the role of ultrasound reflection and scattering in diagnostic imaging is it ___________________.

A) is responsible for enhancement
B) provides clear detail
C) allows us to see the tissue interfaces
D) increases the patient's exposure

Question 79

The ultrasound machine directly measures distance.

Question 80

For perpendicular incidence and equal impedances between media,there is no ________ and the ________ intensity equals the incident intensity.

A) transmission; reflected
B) reflection; transmitted
C) transmission; transmitted
D) reflection; reflected