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1
Q

The effects of the medium upon the sound wave is called?

A

Acoustic propagation properties

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2
Q

The effects of the sound wave upon the biologic tissue is called?

A

Biologic effects

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3
Q

Name the 3 acoustic variables

A

1) Pressure
2) Density
3) Distance

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4
Q

What are the units of density

A

Kg/cm cubed

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5
Q

What are regions of higher density and pressure called

A

Compressions

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6
Q

What are regions of lower density and pressure called?

A

Rarefractions

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7
Q

Name the 7 parameters that describe sound waves

A

1) Period
2) Frequency
3) Amplitude
4) Power
5) Intensity
6) Wavelength
7) Speed

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8
Q

The time required to complete a single cycle is called

A

Period

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9
Q

What are the units of period and how is it determined. Can period be adjusted by the songrapher

A

Units: seconds (any unit of time)
Determined by: Sound source
CANT be changed

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10
Q

The number of cycles that occur in one second is called?

A

Frequency

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11
Q

Why is frequency important? and how is it determined

A

Affects penetration and image quality

Determined by sound source

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12
Q

How are period and frequency related?

A

Reciprocals and inversely related

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13
Q

What is the equation for period and frequency

A 
period= 1/ frequency 
frequency= 1/period
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14
Q

The difference between the average value and the max value of an acoustic variable is called

A

Amplitude

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15
Q

What are the units of amplitude, how is it determined, and can it be changed?

A

Units: decibels
Determined by: Sound source
CAN be changed

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16
Q

Does amplitude increase or decrease as it propagates through the body?

A

Decreases

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17
Q

How is power determined and can it be changed?

A

Determined by: Sound source

CAN be changed

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18
Q

Does power increase or decrease as sound propagates through the body?

A

Decreases

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19
Q

What is the relationship between power and amplitude?

A

Power is proportional to the waves amplitude squared

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20
Q

If the amplitude is doubled what is the power increased by a factor of?

A

Power is increased by a factor of 4 (quadrupled)

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21
Q

The concentration of energy in a sound beam describes?

A

Intensity

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22
Q

What is the equation of intensity

A

Intensity= power/beam area (cm2)

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23
Q

How is intensity determined and can it be changed?

A

Determined by: sound source

CAN be changed

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24
Q

Does intensity increase or decrease as sound propagates through the body?

A

Decreases

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25
Q

How is intensity and power related

A

Directly

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26
Q

True or False

Intensity is proportional to the amplitude of the wave sqaured

A

True

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27
Q

What is the length or distance of a single cycle?

A

Wavelength

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28
Q

What are the units of wavelength?
How is it determined and can it be changed?
What are the typical values

A

Units: meters
Determined by: Both source and medium
CANT be changed
Values: 0.1-08 mm

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29
Q

What is the equation for wavelength

A

wavelength= propagation speed/frequency

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30
Q

Higher frequency results of what kind of wavelength?

A

Shorter wavelength

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31
Q

What is the equation of wavelength in soft tissue?

A

wavelength= 1.54 mm/ frequency

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32
Q

What is the rate that sound travels through a medium

A

Propagation speed

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33
Q

What are the units of propagation speed? How is it determined and can it be changed?

A

Units: meters per second
Determined by: Medium
CANT be changed

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34
Q

How are wavelength and speed related

A

Directly

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35
Q

What is the equation for speed?

A

Speed= frequency X wavelength

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36
Q

True or False

Speed only changed if the medium changes

A

True

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37
Q

The time from the start of a pulse to the end of a pulse describes

A

Pulse duration

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38
Q

What is the equation for pulse duration

A

pulse duration= # of cycles/ frequency

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39
Q

What are the units of pulse duration
How is pulse duration determined
Can it be changed
What are the typical values

A

Units: seconds
Determined by: Sound
CANT be changed
Values: 2-4 cycles

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40
Q

The time from the start of one pulse to the start of the next pulse describes

A

Pulse repetition period

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41
Q

What are the units of PRP
How is it determined
Can it be changed

A

Units: seconds (msec)
Determined by: Sound
CAN be changed

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42
Q

What happens to PRP as it increases

A

The imaging depth increases

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43
Q

The number of pulses that occur in one second describes

A

Pulse repetition frequency

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44
Q

What is the importance of PRF

A

depends solely upon imaging depth and in unrelated to frequency

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45
Q

How is PRF determined
Can it be changed
What are the typical values

A

Determined by sound
CAN be changed
Values: 1,000-10,000 hz or 1-10khz

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46
Q

When PRF is high what happens to the image

A

Image is more shallow

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47
Q

The length or distance that a pulse occupies in space is called

A

Spatial pulse length

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48
Q

What are the units of SPL
How is it determined
can be it changed

A

Units:mm, meters
Determined by: Both
CANT be changed

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49
Q

Do shorter pulses create higher or lower quality images

A

Higher quality images

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50
Q

What is the equation for SPL

A

SPL= # of cycles X wavelength

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51
Q

What intensity is the biggest

A

SPTP

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52
Q

Which intensity is most important for thermal bioeffects

A

SPTA

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53
Q

Which intensity is the smallest

A

SATA

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54
Q

What term describes a logarithmic scale

A

Decibels

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55
Q

A decrease in intensity, power, and amplitude of a sound wave as it travels describes

A

Attenuation

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56
Q

What are the units of attenuation

A

Decibels

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57
Q

What 2 things does attenuation of a sound in soft tissue depend on

A

1) The distance the wave travels

2) Frequency

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58
Q

What are the 3 components of attenuation

A

1) Absorption
2) Scattering
3) Reflection

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59
Q

This occurs when propagating sound energy strikes a boundary between 2 media and some returns to the transducer

A

Reflection

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60
Q

What type of reflection is smooth and returns in one direction

A

Specular

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61
Q

What type of reflection is rough and when reflected the sound is disorganized and random

A

Diffuse

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62
Q

If the boundary between 2 media have irregularities then the wave redirects in all directions describes

A

Scattering

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63
Q

This type of scattering occurs when a reflector is much smaller than the wavelength and the sound is uniformly distributed in all directions

A

Rayleigh

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64
Q

What are the units of attenuation coefficent

A

dB/cm

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65
Q

As frequency of sound increases what happens to the attenuation coefficient

A

Increases

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66
Q 
Which of the following is the best estimate for attenuation coefficient of sound traveling in soft tissue?
A) 1.8 dB/cm/MHz
B) 0.77 dB/cm/MHz
C) 0.45 dB/cm/MHz
D) 1.0 dB/cm/MHz
A

C) because it is closest to 0.5

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67
Q

How is impedance determined

What are the units

A

Determined: Medium
Units: Rayls or “Z”

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68
Q

What are 4 other names for normal incidence

A

Perpendicular
Orthogonal
Right angle
90 degrees

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69
Q

What incidence is anything other than 90 degrees or not at right angles?

A

Oblique incidence

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70
Q

What intensity is the sound wave at the instant prior to striking a boundary?

A

Incident intensity

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71
Q

What intensity is after striking a boundary it changes direction and returns back from where it came

A

Reflected intensity

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72
Q

What intensity occurs after striking a boundary and continues on in the same general direction that it was originally traveling?

A

Transmitted intensity

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73
Q

What is the unit for all intensites

A

W/cm2

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74
Q

What is the equation for incident intensity

A

Incident intensity= reflected intensity+ transmitted intensity

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75
Q

What intensity coefficient occurs when the percentage of the US intensity bounces back when the sound strikes the boundary

A

Intensity Reflection coefficient (IRC)

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76
Q

What intensity coefficient occurs when the percentage of the US intensity that is allowed to pass through when the beam reaches a boundary between 2 media

A

Intensity Transmission coefficient (ITC)

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77
Q

True or False

Coefficients are reported in without units and are reported in percentages

A

True

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78
Q

In soft tissue what percentage of intensity is reflected back at an air tissue interface

A

99%

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79
Q

In soft tissue what percentage of intensity is reflected at a bone tissue interface

A

50%

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80
Q

With normal incidence what occurs only if the 2 media at the boundary have different acoustic impedances

A

Reflection

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81
Q

Transmission with a bend is called

A

Refraction

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82
Q

Refraction occurs when what 2 conditions are met

A

1) oblique incidence

2) Different propagation speeds

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83
Q

What law describes the physics of refraction

A

Snell’s law

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84
Q 
Which of these media have the greatest attenuation and the slowest speed?
A) bone
B) Tendon
C) Fat
D) Air
A

D) air

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85
Q 
Which of these media have the greatest attenuation and the fastest speed?
A) Bone
B) Tendon 
C) Lung 
D) Fat 
E) Air
A

A)Bone

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86
Q

The time needed for a pulse to travel to and from the transducer and reflector is called

A

Time of flight

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87
Q

True or false

In soft tissue every 13 seconds of go return time means the reflector is 1 cm deeper in the body>

A

True

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88
Q

What is the equation for time of flight

A

Depth (mm)= 1.54 mm X go return time/ 2

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89
Q

Any device that converts one form of energy into another is

A

Transducer

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90
Q

What is a property of certain materials to create a voltage when pressure is applied or when they are mechanically deformed called

A

Piezoelectric effect

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91
Q

What is anther name for the piezoelectric effect

A

Ferroelectric material

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92
Q

What material is the piezoelectric made out of

A

Lead zirconate titanate

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93
Q

What is the complete destruction of all living microorganisms by means of exposure to heat, chemical agents, or radiation

A

Sterilization

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94
Q

This refers to the application of a chemical agent to reduce or eliminate infectious organisms on an object such as a transducer

A

Disinfection

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95
Q

How thick if the active element

A

1/2 wavelength thick

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96
Q

This part of the transducer protects the internal components from damage and insulates the patient from electric shock

A

Case

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97
Q

This part of the transducer has an impedance between those of the skin and the active element to increase the percentage of transmitted US between the active element and the skin

A

Matching layer

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98
Q

How thick is the matching layer

A

one quarter wavelength thick

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99
Q

True or false

Short pules create better images

A

True

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100
Q

This part of the transducer is bonded to the active element to reduce its ringing and is commonly made of epoxy resin impregnated with tungsten

A

Damping element

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101
Q

What is another name for the damping element

A

Backing material

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102
Q

The range of frequencies between the highest and the lowest frequency emitted from the transducer describes

A

Bandwidth

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103
Q

When compared to therapeutic transducers, do imaging transducers use a wide or narrow bandwith

A

Wide

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104
Q

This represents the extent of damping and is a unitless number

A

Quality factor

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105
Q

When compared to therapeutic transducers do imaging transducers use a low or high Q

A

Low

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106
Q

This describes the sound waves frequency equal to the frequency of the voltage applied to the PZT by the machines electronics

A

Continuous wave transducer

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107
Q

The main frequency of the US for a pulsed transducer is determined by what 2 characteristics of the crystal

A

1) The thickness

2) The propagation speed of the piezoelectric material

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108
Q

For pulsed ultrasound when the frequency is higher is the crystal thick or thin? Is the PZT fast or slow

A 
Crystal= thin
PZT= fast
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109
Q

For pulsed ultrasound when the frequency is low is the crystal thick or thin? Is the PZT fast or slow

A 
Crystal= thick
PZT= slow
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110
Q

What is another name for the focus

A

Focal point

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111
Q

the location where the beam is the narrowest is called

A

The focus

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112
Q

What are 2 other names for the near zone

A

1) Near field

2) Fresnel zone

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113
Q

What zone is the region from the transducer to the focus called

A

Near zone

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114
Q

What are 2 other names for the focal length

A

1) Focal depth

2) Near zone length

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115
Q

What zone is the distance from the transducer to the focus

A

Focal Length

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116
Q

What are 2 other names for the far zone

A

1) Far field

2) Fraunhofer zone

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117
Q

What is the region around the focus where the beam is relatively narrow

A

Focal zone

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118
Q

Adjustable focus systems are called

A

Phased array

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119
Q

With a fixed focus transducer what are 2 factors that determine the focal depth

A

1) Transducer diameter

2) Frequency of sound

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120
Q

How are transducer diameter and focal depth related

A

Directly

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121
Q

How are frequency and focal depth related

A

Directly

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122
Q 
Which of the following probes creates a beam with the shallowest focus
A) Small diameter, high frequency
B) Large diameter, high frequency
C) Small diameter, low frequency,
D) Large diameter, low frequency
A

C because shorter focal lengths are associated with small diameter low frequency probes

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123
Q

What describes the gradual spread of the ultrasound bream in the far field

A

Beam divergence

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124
Q

What 2 factors combine to determine beam divergence

A

1) Transducer diameter

2) Frequency of the sound

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125
Q

How are crystal diameter and beam divergence related

A

Inversely

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126
Q

True or false

Smaller diameter crystals produce beams that spread out more in the far field

A

True

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127
Q

Do small or large diameter crystals improve lateral resolution in the far field

A

Large because the crystals create sound beams that diverge less in the far field

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128
Q

V-shaped waves are known as what 3 things

A

1) spherical waves
2) diffraction patterns
3) huygens’ wavelets

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129
Q

What shape does large PZT crystals create

A

Hour glass figure

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130
Q

Do narrow beams create better or worse images

A

Better

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131
Q

Do sound beams diverge or converge in the near zone

A

Converge

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132
Q

Do sound beams diverge or converge in the far zone

A

Diverge

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133
Q 
Which of the following transducers has the best lateral resolution in the far field
A) 4 HMz, 4 mm crystal diamter
B) 6 MHz, 4 mm crystal diamter
C) 4 MHz, 6 mm crystal diameter
D) 6 MHz, 6 mm crystal diamter
A

D)

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134
Q

The ability to distinguish two structures that are close to eachother front to back parallel to or along t he beams main axis is called

A

Axial resolution

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135
Q

What are 4 other names for axial resolution

A

Longitudinal
Axial
Range or radial
Depth

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136
Q

Do shorter pulses provide better or worse images

A

Better

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137
Q

What are the units for axial resolution

A

mm

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138
Q

With axial resolution what type of frequency and wavelength are needed for the best images

A

High frequency short wavelength

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139
Q

The minimum distance that 2 structures are separated by side to side or perpendicular to the sound beam that produces 2 distinct echoes is called

A

Lateral resolution

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140
Q

What are 4 other names for lateral resolution

A

Lateral
Angular
Transverse
Azimuthal

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141
Q

Which resolution is better axial or lateral

A

Axial

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142
Q

Lateral resolution is best at what point of the transducer

A

Best at the focus or near zone because the sound beam is narrowest at that point

143
Q

True or false

Since the beam diameter varies with depth, the lateral resolution also varies with depth

A

True

144
Q

Focusing alters the beam in what 3 ways

A

1) narrower in the US beam
2) Shallower focus
3) Smaller focal zone

145
Q

Where in the transducer is focusing mainly effective

A

In the near field and the focal zone

146
Q

What are the 3 specific types of foucisng

A

1) Lens
2) Curved
3) Electronic

147
Q

This type of focusing is external

A

Lens

148
Q

This type of focusing is internal

A

Curved

149
Q

What type of transducers have the poorest lateral resolution

A

Fixed focus since the focal depth is fixed and cant be adjusted

150
Q

What type of transducers have the best lateral resolution

A

Phased array because the focal depth can be adjusted

151
Q

This type of mode a dot moves across the display at a constant speed and when the echo returns an deflection proportional to the amplitude of the returning echo is observed

A

A- mode (amplitude)

152
Q

In A mode which axis represents depth

A

X axis

153
Q

In A mode which axis represents amplitue

A

Y axis

154
Q

This type of mode the returning echoes are presented as spots on the line of travel of the emitted US pulse

A

B-mode (brightness)

155
Q

In B mode which axis is represents depth

A

X axis

156
Q

In B mode which axis represents the brightness of the dot

A

Z axis

157
Q

Which mode is the only mode that displays the changing position of reflectors with respect to time

A

M-mode

158
Q

In M mode which axis represents time

A

X axis

159
Q

In M mode which axis represents depth

A

Y axis

160
Q

For mechanical scanning how many active elements do the crystals contain?

A

1 active element

161
Q

For mechanical scanning the crystal element is shaped like what?

A

Disc shaped

162
Q

In mechanical scanning what is the image shaped like

A

Fan or sector shape

163
Q

What type of transducer is a collection of active elements in a single transducer

A

Array

164
Q

This type of transducer is a collection of elements in a line

A

Linear array

165
Q

This type of transducer is a group of ringed elements (bull’s eye) with a common center

A

Annular array

166
Q

This type of transducer the elements are arranged in an arc

A

Convex or curved array

167
Q

Approx how many elements are arranged in a line for a linear array

A

200

168
Q

What element shape does a linear array have

A

Rectangle

169
Q

This type of array fires at exactly the same time to create a narrow directional beam. What type of resolution does it improve

A

Linear. Improves lateral resolution

170
Q

This type of array the scan lines are parallel and are equally spaced

A

Linear

171
Q

In mechanical scanning what happens to the image when a crystal is defective

A

The entire image is destroyed

172
Q

What is another name for swithched array

A

Sequential

173
Q

In linear arrays when a crystal is defective what happens to the image

A

There is dropout extending from superficial to deep

174
Q

This type of array can be adjusted or multi focus and is achieved electronically

A

Phased

175
Q

Approx how many crystals are in a phased array

A

100-500

176
Q

What type of image shape does a phased array make

A

A fan or sector shape

177
Q

In this type of array the elements are fired nearly simultaneoulsy

A

Phased

178
Q

In a phased array when there is no steering what happens to the focus

A

there is no transmit focus

179
Q

In a phased array when there is upward steering what happens to the focus

A

There is not transmit focusing

180
Q

In a phased array when there is a defective crystal what happens to the image

A

If one element malfunctions the steering and focusing becomes erratic

181
Q

This system creates electronic patterns and delays are approx 10 nanoseconds

A

Beam former

182
Q

This type of array the crystals are concentric rings cut from the same circular slab of PZT and the array looks like a bull’s eye target

A

Annular phased array

183
Q

In annular phased arrays what happens to the image when a crystal is defective

A

There is a horizontal (side-to side) band of drop out

184
Q

A form of electronic receive electronic focusing is called

A

Dynamic aperature

185
Q

This type of array creates a 3D US image and can measure volume more accurately than 2D.

A

Multidimensional array

186
Q

This type of array is trapezodial and has a flat top that does not come to a point

A

Vector array

187
Q

The ability to accurately locate moving structures at any particular instant in time is called

A

Temporal resolution

188
Q

What does temporal resolution depend on

A

Frame rate

189
Q

What is the fundamental limitation of temporal resolution

A

Speed

190
Q

What are the typical values for frame rate

A

20-100 hz

191
Q

Period multiplied by the number of cycles in a pulse equals

  • Amplitude
  • Wavelength
  • Pulse duration
  • Sound velocity
A

-Pulse duration

192
Q

As wavelength increases:

  • resolution improves
  • frequency decreases
  • depth of penetration increases
  • attenuation decreases
A

-frequency decreases

193
Q

How are period and wavelength related

A

Directly

194
Q

What is the average speed of sound in soft tissue

A

1,540 m/s

195
Q

All of the following are possible units for amplitude except:

  • degrees
  • decibels
  • pascal
  • watts
A

Watts

196
Q

What machine controls affects amplitude

A

Output power

197
Q

What effect will an increase in area have on intensity if power remains unchanged

A

Decrease

198
Q

What is the acoustic characteristic of a medium

A

Impedance

199
Q

Ultrasound transducers utilize which effect upon transmission

A

Reverse piezoelectric

200
Q

The fundamental frequency for pulsed wave transducers is determined primarily by the elements

A

Thickness

201
Q

The impedance value for the damping block is

A

Equal to the active element

202
Q

Which of the following increases with damping:

  • Output intensity
  • Sensitivity
  • Quality factor
  • Bandwidth
A

-Bandwidth

203
Q

Damping improves

A

Radial resolution

204
Q

Methods for reducing the overall beam width in the near field includes all of the following except increase:

  • focus
  • transducer diameter
  • frequency
  • damping
A

-damping

205
Q

A receive focus method utilizing delay lines is called

A

Dynamic

206
Q

Changing pulse duration will affect all of the following except

  • axial resolution
  • lateral resolution
  • spatial pulse length
  • duty factor
A

-Lateral resolution

207
Q

The resolution most affected by spatial pulse length is

A

Longitudinal

208
Q

By increasing the image depth, duty factor

A

increases

209
Q

What instrument control directly affects amplification

A

Overall gain

210
Q

Which of the following has the narrowest dynamic range:

  • transducer
  • amplifier
  • memory
  • display
A

-display

211
Q

The mode that displays returning echoes only from a pre-selected tissue depth is

A

C

212
Q

A 1-bit digital system is considered

A

Bistable

213
Q

A cosine of zero degrees is

A

1

214
Q

A cosine of ninety degrees is

A

0

215
Q

The major advantage of PW Doppler is:

  • range discrimination
  • aliasing
  • Nyquist limit
  • range ambiguity
A

-range discrimination

216
Q

The color flow Doppler artifact associated with the superimposition of color on moving tissue is

A

Ghosting

217
Q

The type of bioeffects mechanism caused by the movement of a mediums particles is

A

Direct mechanical

218
Q

Experimental studies performed in the living body of a plant or animal is called

A

In vivo

219
Q

Experimental studies performed outside the living body in an artificial environment is called

A

In vitro

220
Q

What ultrasound component converts electrical into acoustic energy during transmission

A

Transducer

221
Q

What ultrasound component creates the firing pattern for phased array systems

A

Pulser

222
Q

The function of this component receives timing signal from synchronizer and creates an electrical signal that excites the PZT crystal

A

Pulser

223
Q

True or false

Greater electrical voltage the greater acoustic intensity

A

True

224
Q

This ultrasound component is determined by the excitation voltage from the pulser and piezoelectric crystal vibrates with a magnitude related to pulser voltage

A

Transducer output

225
Q

Changes in transducer output have what affect on the entire image

A

Brightnesss

226
Q

Would you increase or decrease transducer output to improve signal-to-noise ratio

A

Increase

227
Q

What are the 5 receiver operations

A

1) Amplification
2) Compensation
3) Compression
4) Demodulation
5) Rejection

228
Q

This receivers purpose is to increase the strength of all electrical signals in the receiver prior to further processing

A

Amplification

229
Q

This receiver purpose is used to create images of uniform brightness from top to bottom

A

Compensation

230
Q

What will you adjust if you cannot see reflectors in the near or far field on your image

A

Adjust the TGC

231
Q

This receivers purpose is to allow us to see all gray shades and decreases the dynamic range of the signals

A

Compression

232
Q

If a signal with an initial dynamic range of 120 dB is compressed by 35 dB what is he dynamic range

A

120-35= 85 dB

233
Q

This receivers purpose is to change the signal form to one more suitable for TV display.

A

Demodulation

234
Q

What are the 2 steps of demodulation

A

1) Rectification

2) Smoothing

235
Q

This receivers purpose is to display low level echoes only when clinically meaningful and is used to eliminate low level noise in our images

A

Rejection

236
Q

When the image is too bright due to high output power, what happens to lateral and longitudinal resolution

A

Degrades

237
Q

Which choice is best when the image on your ultrasound system displays reflectors only in a region far from the transducer but no reflectors in a region close to the transducer

a) Adjust the systems compensation
b) Use a higher frequency transducer
c) Decrease the output power
d) Adjust the reject level

A

a) Adjust the systems compensatino

238
Q

Which choice is best when the image on your ultrasound system is saturated (too bright everywhere)

a) Decrease the overall amplification or gain
b) Use a higher frequency transducer
c) Decrease the output power
d) Adjust the reject level

A

c) Decrease the output power

239
Q

Which choice is best when the image on your ultrasound system displays only bright reflectors but no weak reflectors throughout the image

a) Increase the systems overall gain
b) Use a higher frequency transducer
c) Increase the output power
d) Adjust the reject level

A

d) Adjust the reject level

240
Q

Which choice is best when the image on your ultrasound system displays only reflectors in a region close to the transducer but not deep

a) Adjust the systems compensation
b) Use a higher frequency transducer
c) Increase the output power
d) Adjust the reject level

A

a) Adjust the systems compensation

241
Q

In what area of a stenotic blood vessel does the max velocity of blood occur

a) within the stenosis
b) before the stenosis
c) before and after the stenosis
d) one cm after the stenosis

A

a) within the stenosis

242
Q

If the frequency doubles, what happens to the wavelength

A

Decreases two fold

243
Q

The type of artifact that produces a reduction in echoes distal to a highly reflective or highly attenuating structure is

A

Shadowing

244
Q

Multipath artifacts result from

a) echoes that return directly to the transducer
b) shot gun pellets
c) echoes that take an indirect path back to the transducer
d) sound wave propagates through a medium at a speed other than soft tissue
e) small amplitude echoes resulting from electrical interference

A

c) echoes that take an indirect path back to the transducer

245
Q

Viscosity is measured in units of

A

Poise

246
Q

When an ultrasound beam passes obliquely across the boundary between two materials, what will occur if there is a difference in acoustic impedance in the two materials

a) reflection, impedance
b) reflection, density
c) refraction, propagation speed
d) refraction, impedance

A

c) refraction, propagation speed

247
Q

What ultrasound method requires 2 active elements mounted side by side

A

Continuous wave doppler

248
Q

The axial resolution of a transducer can be improved with____ but at the expense of _____

a) increased damping, sensitivity
b) frequency, lateral resolution
c) focusing, sensitivity
d) focusing, lateral resolution
e) beam width, lateral resolution

A

a) increased damping, sensitivity

249
Q

Which of the following is NOT an acoustic variable

a) density
b) pressure
c) temperature
d) force

A

d) force

250
Q

Improper location of an echo may be attributable to

A

propagation speed error

251
Q

What is the most common result of high intensity ultrasound

A

Heat

252
Q

Normal incidence is the term used when the ultrasound beam strikes a boundary between 2 media at what angle

A

Orthogonal

253
Q

An artifact that is produced from interaction to the incident beam with a curved surface and that results in an acoustic shadow is referred to as

A

Edge artifact

254
Q

When the piezoelectric crystal continues to vibrate after the initial voltage pulse, this is referred to as

A

Ring down time

255
Q

The range equation relates

a) frequency, velocity, wavelength
b) frequency, velocity, time
c) distance, velocity, time
d) distance, frequency, time
e) incidence, reflection, refraction

A

c) distance, velocity, and time

256
Q

The development of an electrical charge across the crystal thickness following deformation describes

A

Piezoelectric effect

257
Q

Real time ultrasound transducers can be classified as

A

Phased, linear, annular, and vector

258
Q

Which of the following ultrasound beams has a characteristic that is most likely to cause temp elevation in soft tissue

a) strongly focused
b) medium focused
c) unfocused

A

c) unfocused

259
Q

One reason focused ultrasound beams with low intensities are less likely to cause bioeffects is that a focused beam is less efficient in heating a large mass of tissue to critical temp

A

True

260
Q

The diameter of a disc shaped, unfocused piezoelectric crystal is 1 cm. What is the best estimate for the minimum lateral resolution of the ultrasound system

a) 1 mm
b) 5 mm
c) 1 cm

A

b) 5 mm

261
Q

Acoustic impedance is a property of the____ and has units of___

A

Medium, Rayls

262
Q

What causes enhancement artifact

a) sound beams bending
b) linear array transducer architecture
c) unexpectedly low acoustic attenuation
d) acoustic energy radiating in a direction other than the beams main axis

A

c) unexpectedly low acoustic attenuation

263
Q

Where are shadowing artifacts commonly seen on an acoustic scan

a) deeper than a structure with a high impedance
b) shallower than a structure with a low propagation speed
c) deeper than a structure with a high attenuation
d) alongside of a structure with a low elastance

A

c) deeper than a structure with a high attenuation

264
Q

Acoustic focusing of an ultrasound beam may create which artifact

A

Enhancement

265
Q

What is a comet tail artifact fundamental mechanism of formation

A

Reflection

266
Q

Unexpectedly low attenuation results in what artifact

A

Enhancement

267
Q

The damping material helps to decrease the PRP achieved at a given imaging depth

A

False

268
Q

What is the best estimate of the propagation speed of the ferroelectric element of a transducer used in a typical diagnostic imaging laboratory

a) 1.2 mm/microseconds
b) 4.0 m/sec
c) 4.0 mm/microseconds
d) 1.0 km/sec

A

c) 4.0 mm/microseconds

269
Q

These transducer systems typically produce an image that throughout its entire depth, is approx as wide as the ultrasound transducer itsself

  • linear switched array
  • linear phased
  • mechanical
  • annular phased array
  • convex or curvilinear array
  • vector array
A
  • linear switched array
  • convex or curvilinear array
  • vector array
270
Q

Withh these transducers a sector image is produced At the top, the sector is very narrow and tapers to a point

  • Linear switched array
  • linear phased
  • Mechanical
  • Annular phased array
  • Convex or curvilinear array
  • vector array
A
  • linear phased
  • mechanical
  • convex or curvilinear phased
  • vector
271
Q

What is the use of a greater number of channels to receive echoes from ever increasing depth called

A

Dynamic aperature

272
Q

The pulse duration is increased as a result of the presence of backing material

A

False

273
Q

What is the advantage of using a 1 1/2 dimensional array transducer

A

Improved elevational resolution

274
Q

The backing material helps to decrease the duty cycle at a particular PRF

A

True

275
Q

A bit is bistable having a value of what

A

0 or 1

276
Q

What reduces speckle and minimizes shadowing artifacts

A

Compound imaging

277
Q

Define the smallest amount of digital storage

A

Binary digit

278
Q

Define the smallest element of a digital picture

A

Pixel

279
Q

A group of 8 bits is called

A

a byte

280
Q

Manipulating data before storage is in the scan converter is called

A

Preprocessing

281
Q

Manipulating data after it has been stored in the scan converter is called
-This can also only be performed on frozen images

A

Postprocessing

282
Q

An uncompressed signal within a systems receiver has a dynamic range of 135 dB. The receiver compresses the signal by 45 dB what is the dynamic range of the compressed signal

a) 135 dB
b) 45 dB
c) 90 dB
d) 100 dB

A

c) 90 dB

283
Q

A signal in a receiver after compression has a dynamic range of 125 dB. The receiver compressed the signal by 25 dB. what was the initial dynamic range of the signal

a) 125 dB
b) 100 dB
c) 25 dB
d) 150 dB

A

d) 150 dB

284
Q

An ultrasound system is operating in the harmonic mode. The fundamental frequency is 4MHz. What is the transmitted frequency

a) 8 MHz
b) 3 MHz
c) -3 dB
d) 4 MHz

A

d) 4 MHz

285
Q

An ultrasound system is operating in the harmonic mode. The harmonic frequency is 8 MHz. What is the transmitted frequency

a) 8 MHz
b) 3 MHz
c) -3 dB
d) 4 MHz

A

d) 4 MHz

286
Q

All of the following are characteristics of contrast agents except

a) high reflectivity
b) cost effective
c) metabolically inert
d) small enough to flow thru capillaries

A

b) cost effective

287
Q

Which of the following is associated with pulse inversion imaging

a) improved temporal resolution
b) reduced frame rates
c) high frequency phase multipliers
d) amplitude modulation

A

b) reduced frame rates

288
Q

What form of behavior creates harmonics

A

non linear

289
Q

True or False

Pulse inversion harmonics uses narrow bandwidth

A

False

290
Q

The study of blood moving through the circulatory system describes

A

Hemodynamics

291
Q

Name the 3 basic forms of blood flow

A

1) pulsatile
2) Phasic
3) Steady

292
Q

This type of blood flow occurs as a result of cardiac contraction

A

Pulsatile flow

293
Q

This type of flow is a result of respiration

A

Phasic

294
Q

What are the 2 forms of laminar flow

A

1) plug flow

2) parabolic

295
Q

This type of flow occurs when all of the layers and blood cells travel at the same velocity

A

Plug flow

296
Q

What flow is commonly found in a normal physiologic state

A

Laminar flow

297
Q

This type of blood flow is characterized by chaotic flow patterns in many different directions and at many speeds

A

Turbulent

298
Q

What is the Reynolds number for turbulent flow

A

greater than 2,000

299
Q

What is the Reynolds number for laminar flow

A

less than 1,500

300
Q

Name the 3 forms of energy associated with blood

A

1) kinetic
2) pressure
3) gravitational

301
Q

What form of energy is associated with a moving object

A

Kinetic

302
Q

What form of energy is stored or has potential energy

A

Pressure

303
Q

As blood flows through circulation energy it is lost in what 3 ways

A

1) viscous
2) frictional
3) inertial

304
Q

This type of energy loss describes the thickness of a fluid.

  • What are the units is measured in?
  • How is it determined
A

Describes viscous energy

  • Units are poise
  • determined by hematocrit
305
Q

This type of energy loss occurs when flow energy is converted to heat as one object rubs against another

A

Frictional

306
Q

This energy loss relates to the tendency of a fluid to resist changes in its velocity

A

Inertia

307
Q

Narrowing in the lumen of a vessel describes

A

Stenosis

308
Q

The velocity of a stenosis is highest at what portion of a vessel

A

Narrowest part of the lumen

309
Q

This describes the relationship between velocity and pressure in a moving fluid

A

Bernoulli’s principle

310
Q

What is the hydrostatic pressure at all locations within the arterial circulation

A

0 mmHg

311
Q

What is the arterial pressure at the knee of the supine patient

A

140 mmHg

312
Q

What is the arterial pressure in the carotid artery of the neck of the supine patient

A

140 mmHg

313
Q

What is the arterial pressure measured in the toe of the upright patient

A

240 mmHg

314
Q

What is the arterial pressure measured at a patients knee

A

215 mmHg

315
Q

During inspiration does venous flow from the head, arms and IVC increase or decrease

A

Increase

316
Q

During inspiration does venous return to the heart increase or decrease

A

Increase

317
Q

During inspiration does venous flow in the legs increase or decrease

A

decrease

318
Q

During expiration does venous flow from the head, arms, and IVC increase or decrease

A

Decrease

319
Q

During expiration does venous flow in the legs increase or decrease

A

Increase

320
Q

True or False
One reason focused ultrasound beams with low intensities are less likely to cause bioeffects is that a focused beam is less efficient in heating a large mass of tissue to a critical temperature

A

True

321
Q

True or False

It is generlaly believed that the effects of diagnostic ultrasound on biologic media are minimal

A

True

322
Q

Which sound wave is least likely to create cavitation

a) 5 MHz, 2 MPa
b) 2 MHz, 4 MPa
c) 6 MHz, 2 MPa
d) 2 MHz, 2 MPa

A

c) 6 MHz, 2 MPa

323
Q

True or False
The AIUM suggests that in vitro research confirming bioeffects is valuable and valid. Their results are significant and should be direclty applied to the clincial area

A

False

324
Q

What type of artifact causes a reflection to be placed at an incorrect depth

a) lateral incertitude
b) shadowing
c) range ambiguity
d) indeterminate relaxation

A

c) range ambiguity

325
Q

All of the following occur with focusing except

a) lower intensity at the focus
b) shorter near zone length
c) more compact focal zone
d) smaller diameter beam diameter at the end of the near zone

A

a) lower intensity at the focus

326
Q

Which artifact results in improper side by side positioning of reflectors

a) multipath
b) comet tail
c) refraction
d) reverberation

A

c) refraction

327
Q

Side lobe artifact usually results in all of the following except

a) hollow structures appearing filled in on the image
b) reflectors not appearing on an image
c) reflectors appearing in improper locations on the image
d) reflectors appearing in multiple locations on the image

A

b) reflectors not appearing on an image

328
Q

The excitation of array elements with dissimilar voltagesis called____ and is used to___

a) dynamic aperture, reduce refraction
b) subdicing, eliminates lobes
c) apodization, remove flash artifact
d) apodization, reduce lobe artifact

A

d) apodization, reduce lobe artifact

329
Q

With regard to the backing material of a pulsed ultrasound transducer True or False
The damping material helps to decrease the pulse repitition period achieved at a given imaging depth

A

False

330
Q

What helps to determine the frequency of the sound produced by the transducer of a continuous wave ultrasound system

a) piezoelectric crystal diamter
b) piezoelectric crystal thickness
c) damping material density
d) ultrasound system electronics

A

d) ultrasound sysem electronics

331
Q

With regard to the backing material of a pulsed ultrasound transducer True or False
The pulse duration is increased as a result of the presence of backing material

A

False

332
Q

An ultrasonic pulse is traveling in soft tissue. Which of the following is most important in the determination of the frequency of the sound

a) the propagation speed of the ultrasound transducer matching layer
b) the thickness of the transducers backing material
c) the impedance of the transducers matching layer
d) the propagation speed of the transducers active element

A

d) the propagation speed of the transducers active element

333
Q

What component of an ultrasound system is made of lead zirconate titanate (PZT)

A

Transducers active element

334
Q

You are asked to fabricate a pulsed ultrasound transducer with the highest possible frequency. Which piezoelectric crystal would you select

a) 6 mm thick, 4 cm diameter, 4.0 mm/ms
b) 8 mm thick, 2 cm diameter, 6.0 mm/ms
c) 4 mm thick, 9 cm diameter, 5.0 mm/ms
d) 2 mm thick, 6 cm diameter, 6.0 mm/ms

A

d) 2 mm thick, 6 cm diameter, 6.0 mm/ms

335
Q

The maximum imaging depth during an exam is unchanged. A new transducer with a longer pulse duration is used. True or False
The frequency is increased

A

False

336
Q

Typically as an ultrasound wave travels through soft tissue the power of the wave

A

Decreases

337
Q

How many nanoseconds are in 7 seconds

a) 7,000,000
b) 7,000,000,000
c) 7 million
d) 0.00000007

A

b) 7,000,000,000

338
Q

Three sound waves with identical frequencies of 3 MHz have powers of 2 mW, 5 mW, and 15 mW. They all travel through the three media wood, brick, and fat with identical thicknesses of 5 cm. True or False
The waves travel through all 3 media at the same speed since they have identical frequencies

A

False

339
Q

True or False

A sonographer can adjust the duration of an acoustic pulse since it depends upon the pulses propagation speed

A

False

340
Q

An ultrasound pulse propagates from soft tissue through a mass. Sound’s propagation speed in the mass is 1,575 m/s. True or False
The period of the sound wave decreases as it travels through the mass

A

False

341
Q

A PZT crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. True or False
The near zone is the only region where the diameter of the sound beam is smaller than the transducer

A

False

342
Q

The maximum imaging depth during an exam is unchanged. A new transducer with a longer pulse duration is used. True or False
The duty factor is increased

A

TRue

343
Q

What happens to the PRP if the sonographer decreases the max imaging depth achieved in an ultrasound scan

A

Decrease

344
Q

True or False
the period of an ultrasound wave is related to the frequency and is the same, regardless of whether the wave is pulsed or continuous

A

TRue

345
Q

Which of these functions are performed by the receiver of an ultrasound system

a) amplification
b) threshold
c) compensation
d) demodulation
e) all the above

A

e) all the above

346
Q

2 ultrasound transducers are used to perform doppler exams on the same patient These exams are identical except that the transducer frequencies are 5 and 2.5 MHz. Which exam will measure the highest doppler shift

a) 2.5 MHz exam
b) 5 MHz
c) neither
d) cannot be determined

A

b) 5

347
Q

True or False
Velocity mode color doppler and variance mode color doppler will produce identical images when blood flow patterns are turbulent

A

False

348
Q

The information that is processed by a standard duplex ultrasound system includes all of the following except

a) attenuation
b) amplitude
c) frequency
d) time of arrival

A

a) attenuation

349
Q

True or False

Color flow doppler relies on pulsed doppler principles and is immune to aliasing artifact

A

False

350
Q

True or False
On a color doppler image, red always represents flow toward the transducer, whereas blue indicates the flow away from the transducer

A

False

351
Q

All of the following are related to a dedicated CW doppler transducer except

a) wide bandwidth
b) high quality factor
c) higher sensitivity
d) range ambiguity

A

a) wide bandwidth

352
Q

True or False
Velocity mode color doppler and variance mode color doppler will produce identical images when blood flow patterns are laminar

A

True

353
Q

True or False
The appearance of negative velocites in a pulsed doppler display always indicates that red blood cells are moving away from the transducer

A

False

SPI review (1 decks)

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