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AN SPI VOCAB > VOCAB > Flashcards

VOCAB Flashcards

1
Q

Absorption

A

The conversion of sound energy to heat

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2
Q

Acoustic speckle

A

the interference pattern caused by scatterers that produces the granular appearance of tissue on an image

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3
Q

Acoustic variables

A

the changes that occur within a medium as a result of sound traveling through that medium

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4
Q

amplitude

A

the maximum or minimum deviation of an acoustic variable from the average value of that variable; the strength of the reflector

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5
Q

attenuation

A

a decrease in the amplitude and intensity of the sound beam as sound travels through tissue

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6
Q

attenuation coefficient

A

the rate at which sound is attenuated per unit depth

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7
Q

axial resolution

A

the ability to accurately identify reflectors that are arranged parallel to the U/S beam

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8
Q

backscatter

A

scattered sound waves that make their way back to the transducer and produce an image on the display

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9
Q

beam uniformity ratio

A

the ratio of the center intensity to the average spatial intensity; also referred to as the SP/SA factor or beam uniformity coefficient

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10
Q

capacitive micromachined U/S transducers

A

technology used to create comparable transducer technology to piezoelectric materials

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11
Q

compression

A

an area in the sound wave of high pressure and density

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12
Q

continuous wave

A

sound that is continuously transmitted

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13
Q

damping

A

the process of reducing the number of cycles of each pulse in order to improve axial resolution

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14
Q

decibels

A

a unit that establishes a relationship or comparison between two values of power; intensity or amplitude

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15
Q

density

A

mass per unit volume

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16
Q

directly related / directly proportional

A

relationship that implies that if one variable decreases, the other also decreases or if variable increases, the other also increases

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17
Q

distance

A

how far apart objects are; may also be referred to as vibration or displacement

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18
Q

duty factor

A

the percentage of time that sound is actually being produced

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19
Q

elasticity / stiffness

A

the ability of an object to resist compression and relates to the hardness of a medium

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20
Q

frequency

A

the number of cycles per second

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21
Q

half-intensity depth / half-value layer thickness

A

the depth at which sound has lost half of its intensity

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22
Q

hertz

A

a unit of frequency

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23
Q

hydrophone

A

a device used to measure the output intensity of the transducer

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24
Q

impedance

A

the resistance to the propagation of sound through a medium

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25
Q

inertia

A

Newton’s principle that states that an object at rest stays at rest and an object in motion stays in motion, unless acted on by an outside force

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26
Q

intensity

A

the power of the wave divided by the area over which it is spread; the energy per unit area

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27
Q

intensity reflection coefficient

A

the percentage of sound reflected at an interface

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28
Q

intensity transmission coefficient

A

the percentage of sound transmitted at an interface

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29
Q

interface

A

the dividing line between two different media

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30
Q

inversely related / inversely proportional

A

relationship that implies that if one variable decreases the other increases or if one variable increases, the other decreases

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31
Q

longitudinal waves

A

waves in which the molecules of the medium vibrate back and forth in the same direction that the waves are traveling

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32
Q

medium

A

any form of matter; solid, liquid or gas

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33
Q

nonspecular reflectors

A

reflectors that are smaller than the wavelength of the incident beam

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34
Q

normal incidence

A

angle of incidence is 90 degrees to the interface

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35
Q

oblique incidence

A

angle of incidence is less than or greater than 90 degrees to the interface

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36
Q

parameter

A

a measurable quantity

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37
Q

particle motion

A

the movement of molecules due to propagating sound energy

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38
Q

path length

A

distance to the reflector

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39
Q

period

A

the time it takes for one cycle to occur

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40
Q

piezoelectric materials / element / crystal

A

a material that generates electricity when pressure is applied to it, and one that changes shape when electricity is applied to it

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41
Q

power

A

the rate at which work is performed or energy is transmitted

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42
Q

pressure

A

force per unit area or the concentration of force

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43
Q

propagate

A

to transmit through a medium

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44
Q

propagation speed

A

the speed at which a sound wave travels through a medium

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45
Q

pulse duration

A

the time during which the sound is actually being transmitted / “on” time

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46
Q

pulse repetition frequency

A

the number of pulses of sound produced in 1 second

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47
Q

pulse repetition period

A

the time taken for a pulse to occur

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48
Q

pulsed wave

A

sound that is sent out in pulses

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49
Q

rarefaction

A

an area in the sound wave of low pressure and density

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50
Q

rate

A

the fixed quantity owed as the sound beam travels through tissue (related to attenuation)

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51
Q

Rayleigh scatterers

A

small scattering reflectors

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52
Q

reflection

A

the echo; the portion of the sound that returns from an interface

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53
Q

refraction

A

the change in the direction of the transmitted sound beam that occurs with oblique incidence angles and dissimilar propagation speeds

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54
Q

scattering

A

the phenomenon that occurs when sound waves are dispersed into different directions because of the small reflector size compared with the incident wavelength

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55
Q

Snell’s law

A

law used to describe the angle of transmission at an interface based on the angle of incidence and the propagation speeds of the two media

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56
Q

sound

A

a traveling variation in pressure

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57
Q

spatial pulse length

A

the length of a pulse

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58
Q

specular reflections

A

reflections that occur when the sound impinges upon a large, smooth reflector at a 90 degree angle

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59
Q

stiffness

A

the ability of an object to resist compression and relates to the hardness of a medium

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60
Q

total attenuation

A

the total amount of sound in dB that has been attenuated at a given depth

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61
Q

transverse waves

A

type of wave in which the molecules in a medium vibrate at 90 degrees to the direction of travel

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62
Q

ultrasound

A

sound waves of frequencies exceeding the range of human hearing

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63
Q

wavelength

A

the length of a single cycle of sound

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64
Q

aperture

A

the diameter of the piezoelectric element producing the beam

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65
Q

array

A

the transducer with multiple active elements

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66
Q

automatic scanning

A

same as real-time ultrasound

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67
Q

axial resolution

A

the ability to accurately identify reflectors that are arranged parallel to the ultrasound beam

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68
Q

backing material

A

the damping material of the transducer assembly, which reduces the number of cycles produced in a pulse

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69
Q

bandwidth

A

the range of frequencies present within the beam

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70
Q

curved sequenced array

A

the transducer commonly referred to as a curvilinear or convex probe

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71
Q

damping

A

the process of reducing the number of cycles of each pulse in order to improve axial resolution

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72
Q

damping material

A

same as backing material; the part of the transducer assembly that reduces the number of cycles produced in a pulse

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73
Q

depth ambiguity

A

the inability to determine the depth of the reflector if the pulses are sent out too fast for them to be timed

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74
Q

destructive interference

A

occurs when out of phase waves meet; the amplitude of the resultant wave is smaller than either of the original waves

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75
Q

divergence

A

spreading of the beam that occurs in the far zone

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76
Q

element

A

the piezoelectric part of the transducer assembly that produces sound

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77
Q

elevational plane / slice thickness plane

A

the third dimension of the beam

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78
Q

elevational resolution

A

the resolution in the third dimension of the beam; slice thickness plane

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79
Q

far zone / Fraunhofer zone

A

the diverging part of the beam distal to the focal point

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80
Q

focal point

A

the area of the beam with the smallest beam diameter

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81
Q

footprint

A

the portion of the transducer that is in contact with the patient’s skin

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82
Q

four-dimensional ultrasound

A

three-dimensional ultrasound in real time

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83
Q

frame

A

one complete ultrasound range

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84
Q

frame rate

A

the number of frames per second

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85
Q

frequency

A

the number of cycles per second

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86
Q

Huygen’s principle

A

states that waves are the result of the interference of many wavelets produced at the face of the transducer

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87
Q

in-phase

A

waves whose peaks and troughs overlap

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88
Q

lateral resolution

A

the ability to accurately identify reflectors that are arranged perpendicular to the ultrasound beam

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89
Q

lead zirconate titanate

A

the man-made ceramic of which many transducer elements are made (PZT)

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90
Q

linear sequenced array

A

the transducer commonly referred to as the linear probe or transducer

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91
Q

matching layer

A

the component of the transducer that is used to step down the impedence from that of the element to that of the patient’s skin

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92
Q

matrix array transducer

A

transducer that acquires real-time volumes using up to 10,000 elements, compared to the 128 to 512 elements used in standard 1D array transducers

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93
Q

mechanical scanheads

A

transducers with a motor for steering the beam

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94
Q

near zone / Fresnel zone

A

the part of the beam between the element and the focal point

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95
Q

near-zone length

A

the length of the region from the transducer face to the focal point

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96
Q

out of phase

A

waves that are 180 degrees opposite each other; the peak of one wave overlaps the trough of the other and vice versa

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97
Q

phased array

A

the transducer that uses phasing, or small time differences to steer and focus the beam

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98
Q

phasing

A

the method of focusing and/or steering the beam by applying electrical impulses to the piezoelectric elements with small time differences between shocks

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99
Q

piezoelectric

A

the ability to convert pressure into electricity and electricity into pressure

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100
Q

quality factor / Q - factor

A

a measure of beam purity; the operating frequency of the transducer divided by the bandwidth

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101
Q

range resolution

A

the ability to determine how far away a reflector is so it can be displayed on the screen; without range resolution there is depth ambiguity

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102
Q

real time

A

live ultrasound; also known as automatic scanning

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103
Q

resonate

A

to alternatively expand and contract

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104
Q

scan lines

A

created when one or more pulses of sound return from the tissue containing information related to the depth and amplitude of the reflectors

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105
Q

section thickness plane / slice thickness plane

A

the third dimension of the beam

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106
Q

sensitivity

A

the ability of a system to display low-level or weak echoes

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107
Q

spatial pulse length

A

the length of the pulse

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108
Q

spatial resolution

A

the ability of the system to distinguish between closely spaced objects; refers to axial, lateral, contrast, and elevational resolution

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109
Q

three-dimensional ultrasound

A

allows the user to see width, height, and depth; may also be referred to as volume scanning

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110
Q

temporal resolution / frame rate

A

ability to display moving structures in real time

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111
Q

transducer

A

any device that converts one form of energy into another; may also refer to the part of the ultrasound machine that produces sound

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112
Q

tungsten

A

component of the backing material

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113
Q

wavefront

A

the leading edge of a wave which is perpendicular to the direction of the propagating wave; formed as a result of Huygen’s principle

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114
Q

wavelet

A

a small wave created as a result of Huygen’s principle

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115
Q

13 us rule

A

the rule that states that it takes 13 micro-seconds for sound to travel 1 centimeter in soft tissue

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116
Q

acoustic speckle

A

the interference pattern caused by scatterers that produces the granular appearance of tissue on a sonographic image

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117
Q

A mode

A

amplitude mode; the height of the spike on the image is related to the strength (amplitude) of the echo generated by the reflector

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118
Q

ALARA

A

as low as reasonably achievable; the principle that states one should always use the lowest power and shortest scanning time possible to reduce potential exposure to the patient

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119
Q

amplification

A

the part of the receiver that increases or decreases the received echoes equally, regardless of depth

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120
Q

amplitude (strength)

A

the maximum or minimum deviation of an acoustic variable from the average value of that variable; the strength of the reflector

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121
Q

analog to digital (A to D converter)

A

the part of the digital scan converter that converts the analog signals from the receiver to binary for processing by the computer

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122
Q

anechoic

A

without echoes or black

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123
Q

apodization

A

the technique that varies the voltage to the individual elements to reduce grating lobes

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124
Q

artifacts

A

echoes on the screen that are not representative of actual anatomy; or reflectors in the body that are not displayed on the screen

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125
Q

B flow imaging

A

a non-Doppler technology that offers real time imaging of blood flow while scanning in grayscale

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126
Q

B mode

A

brightness mode; the brightness of the dots is proportional to the strength of the echo generated by the reflector

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127
Q

beam former

A

the part of the machine that shapes and steers the beam on the transmit end

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128
Q

binary system

A

the digital language of zeroes and ones

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129
Q

bistable

A

black and white image

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4
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130
Q

bit

A

the smallest unit of memory in a digital device

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131
Q

byte

A

8 bits of memory

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132
Q

cathode ray tube (CRT)

A

display that uses an electron gun to produce a stream of electrons toward a phosphor-coated screen

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133
Q

coded excitation

A

a way of processing the pulse to improve contrast resolution and reduce speckle

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134
Q

comet tail

A

a type of reverberation artifact caused by small reflectors (surgical clips)

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135
Q

compensation / time - gain compensation

A

the function of the receiver that changes the brightness of the echo amplitudes to compensate for attenuation with depth

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136
Q

compression

A

the function of the receiver that decreases the range of signal ampitudes present within the

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137
Q

contrast resolution

A

the ability to differentiate one shade of gray from another

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138
Q

demodulation

A

the function of the receiver that makes the signal easier to process by performing rectification and smoothing

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139
Q

digital-to-analog (D to A) converter

A

part of the digital scan converter that converts the binary signals from computer memory to analog for display and storage

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140
Q

dynamic range

A

the series of echo amplitudes present within the signal

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141
Q

edge shadowing

A

refraction artifact caused by the curved surface of the reflector

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142
Q

electrical interference

A

arc-like bands that occur when the machine is too close to an unshielded electrical device

143
Q

enhancement

A

an artifact caused by sound passing through an area of lower attenuation

144
Q

fill-in interpolation / pixel interpolation

A

places grayscale pixels where there is no signal information based on adjacent scan lines

145
Q

frame

A

one complete ultrasound image

146
Q

frequency compounding

A

averages the frequencies across the image to improve contrast resolution and reduce speckle

147
Q

fundamental frequency

A

the operating or resonating frequency emitted by the transducer

148
Q

grating lobes

A

an artifact caused by extraneous sound that is not located along primary beam path; occurs with arrays; reduced or eliminated by apodization, subdicing, and tissue harmonics

149
Q

harmonics / native tissue harmonic imaging

A

harmonic signal produced by the patient’s tissue and that is a multiple of the fundamental frequency

150
Q

hyperechoic / echogenic

A

displayed echoes that are relatively brighter than the surrounding tissue

151
Q

hypoechoic

A

displayed echoes that are relatively darker than the surrounding tissue

152
Q

liquid crystal display (LCD)

A

display that uses the twisting and untwisting of liquid crystals in front of a light source

153
Q

M mode

A

motion mode, used to display motion of the reflectors

154
Q

master synchronizer

A

the timing component of the ultrasound machine that notes how long it takes for signals to return from reflectors

155
Q

mirror image artifact

A

an artifact caused by the sound bouncing off strong reflectors and causing a structure to appear on both sides of the reflector

156
Q

multipath

A

an artifact caused by the beam bouncing off several reflectors before returning to the transducer

157
Q

noise

A

low-level echoes on the display that do not contribute useful diagnostic information

158
Q

output

A

output power; strength of the sound entering the patient

159
Q

overall gain

A

receiver function that increases or decreases all of the echo amplitudes equally

160
Q

picture archiving and communication system (PACS)

A

a type of display and storage device commonly used in sonography and other imaging modalities

161
Q

pixel (picture element)

A

the smallest component of 2D digital image

162
Q

preamplification

A

occurs at the receiver to the relatively weak signal coming from the transducer; ultimately the signal has to be increased so the rest of the receiver can analyze it

163
Q

preprocessing

A

occurs in the A to D converter; the image must be live

164
Q

propagation speed errors

A

artifact that occurs because the actual propagation speed of the tissue is greater than or less than 1540 meters per second, the machine places the reflector at the wrong location on the display

165
Q

postprocessing

A

occurs in the D to A converter; the image must be frozen

166
Q

pulse inversion technology

A

harmonic technology in which the fundamental frequency is flipped 180 degrees and transmitted, which cancels out the fundamental frequency via destructive interference, leaving only the harmonic signal

167
Q

pulser

A

part of the beam former that controls the amount of energy in the pulse

168
Q

range equation

A

equation used to calculate the distance to the reflector; in soft tissue, d = 0.77t where d is depth of the reflector and t represents the round-trip time of the pulse

169
Q

read zoom

A

the type of magnification performed in the D to A converter (post processing) that magnifies the image by enlarging the pixels

170
Q

receiver / signal processor

A

the component of the machine that processes the signals coming back from the patient

171
Q

rectification

A

the part of the receiver that inverts the negative voltages to positives

172
Q

rejection

A

function of the receiver that is used to reduce image noise; sets a threshold below which the signal will not be displayed

173
Q

reverberation

A

an artifact caused by the beam bouncing between 2 strong reflectors

174
Q

ring down

A

an artifact caused by vibration of air bubbles

175
Q

scan converter

A

the part of the U/S machine that processes the signals from the receiver; consists of the A to D converter, computer memory, and D to A converter

176
Q

scan line

A

created when one or more pulses of sound return from the tissue containing information related to the depth and amplitude of the reflectors

177
Q

shadowing

A

an artifact caused by the failure of sound to pass through a strong attenuator

178
Q

side lobes

A

an artifact caused by extraneous sound that is not found along the primary beam path; occurs with single-element transducers

179
Q

slice thickness artifact / elevational plane artifact

A

artifact that occurs as a result of the beam not being razor thin; thus, unintended echoes may appear in the image as the beam slices through structures adjacent to intended reflectors

180
Q

smoothing

A

part of the demodulation component of the receiver; an envelope is wrapped around the signal to eliminate the humps

181
Q

spatial compounding

A

technique that eliminates edge shadowing because the object is imaged at different angles

182
Q

speckle reduction

A

algorithm used in signal processing to reduce the amount of acoustic speckle

183
Q

specular reflectors

A

large, flat, smooth boundaries that cause reflection

184
Q

subdicing

A

dividing the piezoelectric elements into very small pieces to reduce grating lobes

185
Q

transmit / receive switch

A

ensures the electrical signals travel in the correct direction

186
Q

voxel (volume element)

A

the smallest component of a 3D image

187
Q

write zoom

A

the type of magnification performed in the A to D converter (pre processing) that magnifies the image by redrawing it before it is stored in memory

188
Q

x - axis

A

the plane that is perpendicular to the beam path

189
Q

y - axis

A

the plane that is parallel to the beam path

190
Q

z - axis

A

the brightness (amplitude) of the dots on the display

191
Q

aliasing

A

the wraparound of the spectral or color Doppler display that occurs when the frequency shift exceeds the Nyquist limit; occurs only with pulsed-wave Doppler

192
Q

angle correction

A

the tool used to inform the machine what the flow angle is so that velocities can be accurately calculated

193
Q

auto correlation

A

the color Doppler processing technique that assesses pixels as stationary or in motion

194
Q

BART

A

the acronym used to describe color Doppler scale “blue away, red toward”

195
Q

baseline

A

the operator adjustable dividing line between positive frequency shifts and negative frequency shifts on spectral and color Doppler

196
Q

Bernoulli’s principle

A

the principle that describes the inverse relationship between velocity and pressure

197
Q

bidirectional Doppler

A

the Doppler deice that can detect positive and negative Doppler shifts

198
Q

boundary layer

A

the stationary layer of blood cells immediately adjacent to the vessel wall

199
Q

brightness

A

the term describing the intensity or luminance of the color Doppler display

200
Q

calf muscle pump

A

the muscles in the calf that upon contraction propel venous blood toward the heart

201
Q

capacitance

A

the ability of veins to store blood

202
Q

clutter

A

acoustic noise in the color and/or spectral Doppler signal

203
Q

collateral blood vessels

A

accessory vessels that connect portions of the same blood vessel together

204
Q

color Doppler imaging

A

Doppler shift information presented as a color hue superimposed over the grayscale image

205
Q

color priority

A

the setting for color Doppler that allows the operator to select frequency shift threshold; it determines whether color pixels should be displayed preferentially over grayscale pixels

206
Q

continuity equation

A

the equation that describes the change in velocity as the area changes in order to maintain the volume of blood flow

207
Q

continuous wave Doppler

A

Doppler device that uses continuous wave U/S transmission; a device that consists of two elements, one element is used by the system to constantly transmit sound and the other is used to constantly receive sound

208
Q

critical stenosis

A

the point at which a stenosis is hemodynamically significant within a pressure drop distal to the stenosis

209
Q

depth ambiguity

A

the inability to determine the depth of the reflector if the pulses are sent out too fast for them to be timed

210
Q

diastole

A

the relaxation of the heart following contraction

211
Q

Doppler effect

A

the change in the frequency of the received signal related to motion of reflector

212
Q

Doppler equation

A

the equation that explains the relationship of the Doppler frequency shift to the frequency of the transducer; the velocity of the blood, the angle to blood flow and the propagation speed

213
Q

duplex

A

real-time 2D imaging combined with the spectral Doppler display

214
Q

effective resistance

A

the sum of the individual resistances when multiple vessels are connected in series

215
Q

energy gradient

A

the difference in energy between 2 points

216
Q

ensemble length / packet size

A

the number of pulses per scan line in color Doppler

217
Q

extrinsic pressure

A

pressure applied to the outside of an object

218
Q

fast Fourier transform

A

a mathematical process used for analyzing and processing the Doppler signal to produce the spectral waveform

219
Q

flash artifact

A

a motion artifact caused by the movement of tissue when using power doppler

220
Q

flow

A

the volume of blood per unit time; typically measured in liter per minute or mililiter per second; represented by the symbol Q

221
Q

frequency shift

A

the difference between the transmitted and received frequencies

222
Q

friction

A

a form of resistance caused by 2 materials rubbing against each other; thereby converting energy to heat

223
Q

hemodynamics

A

the study of blood flow through the blood vessels of the body

224
Q

hue

A

a term used to describe displayed colors

225
Q

hydrostatic pressure

A

describes the relationship between gravity, density of the blood, and distance between an artery’s reference point

226
Q

aliasing

A

the wraparound of the spectral or color Doppler display that occurs when the frequency shift exceeds the Nyquist limit; occurs only with pulsed-wave Doppler

227
Q

angle correction

A

the tool used to inform the machine what the flow angle is so that velocities can be accurately calculated

228
Q

autocorrelation

A

the color Doppler processing technique that assesses pixels as stationary or in motion

229
Q

BART

A

the acronym used to describe color Doppler scale

230
Q

baseline

A

the operator-adjustable dividing line between positive frequency shifts and negative frequency shifts on spectral and color Doppler

231
Q

Bernouilli’s principle

A

the principle that describes the inverse relationship between velocity and pressure

232
Q

bidirectional Doppler

A

the Doppler device that can detect positive and negative Doppler shifts

233
Q

boundary layer

A

the stationary layer of blood cells immediately adjacent to the vessel wall

234
Q

brightness

A

the term describing the intensity or luminance of the color Doppler display

235
Q

calf muscle pump

A

the muscles in the calf that, upon contraction, propel venous blood toward the heart

236
Q

capacitance

A

the ability of veins to store blood

237
Q

clutter

A

acoustic noise in the color and/or spectral Doppler signal

238
Q

collateral blood vessels

A

accessory vessels that connect portions of the same blood vessel together

239
Q

color Doppler imaging

A

Doppler shift information presented as a color hue superimposed over the grayscale image

240
Q

color priority

A

the setting for color Doppler that allows the operator to select frequency shift threshold; it determines whether color pixels should be displayed preferentially over grayscale pixels

241
Q

continuity equation

A

the equation that describes the change in velocity as the area changes in order to maintain the volume of blood flow

242
Q

continuous wave Doppler

A

Doppler device that uses continuous wave U/S transmission; a device that consists of 2 elements, one element is used by the system to constantly transmit sound and the other is used to constantly receive sound

243
Q

critical stenosis

A

the point at which a stenosis is hemodynamically significant with a pressure drop distal to the stenosis

244
Q

depth ambiguity

A

the inability to determine the depth of the reflector if the pulses are sent out too fast for them to be timed

245
Q

diastole

A

the relaxation of the heart following contraction

246
Q

Doppler effect

A

the change in the frequency of the received signal related to motion of reflector

247
Q

Doppler equation

A

the equation that explains the relationship of the Doppler frequency shift to the frequency of the transducer, and the propagation speed

248
Q

duplex

A

real-time 2D imaging combined with the spectral Doppler display

249
Q

effective resistance

A

the sum of the individual resistances when multiple vessels are connected in series

250
Q

energy gradient

A

the difference in energy between 2 points

251
Q

ensemble length / packet size

A

the number of pulses per scan line in color Doppler

252
Q

extrinsic pressure

A

pressure applied to the outside of an object

253
Q

fast Fourier transform

A

a mathematical process used for analyzing and processing the Doppler signal to produce the spectral waveform

254
Q

flash artifact

A

a motion artifact caused by the movement of tissue when using power Doppler

255
Q

flow

A

the volume of blood per unit time; typically measured in liter per minute or mililiter per second (represented by Q)

256
Q

frequency shift

A

the difference between the transmitted and received frequencies

257
Q

friction

A

a form of resistance; caused by 2 materials rubbing against each other, converting energy to heat

258
Q

hydrostatic pressure

A

describes the relationship between gravity, density of the blood, and distance between an arbitrary reference point

259
Q

inertia

A

Newton’s principle that states that an object at rest stays at rest and an object in motion stays in motion, unless acted on by an outside force

260
Q

innervated

A

supplied with nerves

261
Q

kinetic energy

A

the energy form of flowing blood

262
Q

laminar flow

A

the flow profile represented by blood that travels in nonmixing layers of different velocities, with the fastest flow in the center and the slowest flow near the vessel walls

263
Q

law of conservation of energy

A

the total amount of energy in a system never changes, although it might be in a different form from which it started

264
Q

luminance

A

the brightness of the color Doppler image

265
Q

mm Hg

A

milimeters of mercury

266
Q

noise

A

low-level echoes on the display that do not contribute useful diagnostic information

267
Q

nondirectional Doppler

A

Doppler device that cannot differentiate between positive and negative frequency shifts

268
Q

nonhemodynamically significant stenosis

A

a stenosis that does not necessarily compromise blood flow to organs or structures

269
Q

Nyquist limit

A

the maximum frequency shift sampled without aliasing; equal to one half the PRF

270
Q

Ohm’s Law

A

a law used in electronics in which flow is equal to the pressure differential divided by resistance

271
Q

oscillator

A

the component of a continuous - wave Doppler device that produces the voltage that drives the transducer

272
Q

persistence

A

the averaging of color frames in order to display blood flow with a low signal-to-noise ratio

273
Q

phase quadrature

A

the component of the Doppler device that determines positive opposed to negative frequency shifts and direction of blood flow

274
Q

phasic flow

A

the characteristic waveform of peripheral veins; flow is determined by respiratory variations as a result of intrathoracic pressure changes

275
Q

phasicity

A

in arteries, the phasicity describes the shape of the waveform based on the resistiveness of the distal bed (multiphasic/monophasic) in veins, phasicity describes the flow pattern that results from respiratory variation (respiratory phasicity)

276
Q

plug flow

A

the flow profile represented by blood typically flowing at the same velocity

277
Q

Poiseuille’s Law

A

the law that describes the relationship of resistance, pressure, and flow

278
Q

potential energy

A

pressure energy created by the beating heart

279
Q

power Doppler / amplitude Doppler

A

Doppler mode in which the signal is determined by the amplitude (strength) of the shift, not the shift itself, amplitude is directly proportional to the number of red blood cells

280
Q

pressure gradient

A

the difference between pressures at two points of a blood vessel

281
Q

pulsatility

A

blood that flows in a pattern representative of the beating heart, with increases and decreases in pressure and blood flow velocity

282
Q

pulsatility index

A

Doppler measurement used to determine how pulsatile a vessel is over time

283
Q

pulse repetition frequency

A

the number of pulses of sound produced in 1 second

284
Q

pulsed-wave Doppler

A

the Doppler technique that uses pulses of sound to obtain Doppler signals from a user-specified depth

285
Q

range gate

A

the gate placed by the operator in the region where Doppler sampling is desired; used with pulsed-wave Doppler

286
Q

range resolution

A

the ability to determine the depth of echoes by timing how long it takes for the echoes to go from the transducer to the reflector and back; utilized by pulsed wave devices

287
Q

rayleigh scatterers

A

very small reflectors (RBC’s)

288
Q

resistance

A

the downstream impedence to flow; determined by vessel length, vessel radius, and viscosity of blood

289
Q

resistive index

A

Doppler measurement used to quantitate the resistiveness of the distal bed

290
Q

Reynolds number

A

the formula used to quantitate the presence of turbulence; Reynolds numbers greater than 2000 typically indicate turbulence

291
Q

sample volume

A

the area within the range gate where the Doppler signals are obtained

292
Q

saturation

A

the amount of white added to a hue; the more white there is, the less saturated the color

293
Q

scale / PRF (in spectral / color Doppler)

A

the spectral Doppler / color Doppler tool that controls the number of pulses transmitted per second to obtain the Doppler information;

294
Q

speckle tracking

A

the method used to obtain the strain information

295
Q

spectral broadening

A

the filling of the spectral window

296
Q

spectral window

A

the area underneath the envelope on the spectral display

297
Q

stenosis

A

pathologic narrowing of a blood vessel

298
Q

strain

A

the changing of the shape of the muscle as it lengthens and contracts

299
Q

sweep speed

A

the operator-adjustable spectral Doppler control that increases or decreases the number of heartbeats visualized on spectral display

300
Q

systole

A

the time period of the cardiac cycle when the heart is contracting

301
Q

tardus parvus

A

an arterial waveform shape with a delayed peak systolic upstroke that indicates proximal obstruction

302
Q

thrombus

A

combination of platelets, red blood cells, and fibrin that make up a blood clot

303
Q

tissue Doppler imaging

A

color DOppler imaging technique used to document wall motion

304
Q

transmural pressure

A

the difference in pressure inside a vessel compared to the pressure outside of the vessel

305
Q

triplex

A

the ability to visualize real time grayscale, color Doppler, and spectral Doppler simultaneously

306
Q

tunica adventitia

A

the outer layer of a blood vessel

307
Q

tunica intima

A

the inner layer of a blood vessel which is closest to the flowing flood

308
Q

tunia media

A

the middle, muscular layer of blood vessel

309
Q

turbulent flow

A

chaotic, disorderly flow of blood

310
Q

variance mode

A

the color Doppler scale with mean velocities displayed vertically on the scale and turbulence displayed horizontally

311
Q

vasa vasorum

A

a network of small blood vessels that supply blood to the walls of arteries and veins

312
Q

vasoconstriction

A

the narrowing of a blood vessel caused by the contraction of the vessel wall

313
Q

vasodilatation

A

the widening of a blood vessel caused by the relaxation of the vessel wall

314
Q

velocity mode

A

the color Doppler scale with mean velocities displayed vertically

315
Q

viscous energy

A

the energy loss caused by friction

316
Q

wall filter / high - pass filter

A

the operator control that eliminates low frequency, high amplitude signals caused by wall or valve motion

317
Q

Z axis

A

the brightness/amplitude of the dots on a B-mode display; the brighter the dots of the spectral waveform, the more red blood cells that make up the signal

318
Q

axial resolution

A

the ability to accurately identify reflectors that are arranged parallel to the U/S beam

319
Q

contrast resolution

A

the ability to differentiate one shade of gray from another

320
Q

Doppler phantom

A

the test object used to evaluate the flow direction, the depth capability or penetration of the DOppler beam, and the accuracy of the sample volume location and measured velocity

321
Q

elevational plane / slice -thickness plane

A

the resolution in the 3rd dimension of the beam

322
Q

horizontal calibration

A

the ability to place echoes in the proper location horizontally and perpendicular to the sound beam

323
Q

lab accreditation

A

a voluntary process that acknowledges an organization’s competency and credibility according to standards and essentials set forth by a reliable source

324
Q

lateral resolution

A

the ability to accurately identify reflectors that are arranged perpendicular to the U/S beam

325
Q

preventative maintenance

A

a methodical way of evaluating equipment’s performance on a routine basis to ensure proper and accurate equipment function

326
Q

quality assurance program

A

a planned program consisting of scheduled equipment testing activities that confirm the correct performance of equipment

327
Q

registration

A

the ability to place echoes in the correct location

328
Q

sample volume

A

the area within the range gate where the Doppler signals are obtained

329
Q

sensitivity

A

the ability of a system to display low-level or weak echoes

330
Q

slice thickness phantom

A

the test object that evaluates the elevational resolution, or the thickness portion, of the sound beam perpendicular to the imaging plane

331
Q

tissue equivalent phantom

A

the test object that mimics the acoustic properties of human tissue and is used to ensure proper equipment performance

332
Q

vertical depth

A

the distance from the transducer

333
Q

acoustic cavitation

A

the production of bubbles in a liquid medium

334
Q

acoustic radiation force impulse imaging

A

uses acoustic radiation force to compress the soft tissue and provides a qualitative measurement of stiffness without requiring pressure input from the sonographer

335
Q

ALARA

A

As Low As Reasonably Achievable / keep patient exposure minimal

336
Q

automatic external defibrillator

A

a portable device that is used to detect and treat abnormal heart rhythms with electrical defibrillation

337
Q

contrast enhanced U/S (CEUS)

A

type of imaging in which an U/S contrast agent containing microscopic gas bubbles is used to improve visualization of structures or blood flow

338
Q

diabetes mellitus

A

a group of metabolic diseases that result from a chronic disorder of carbohydrates metabolism

339
Q

diabetic ketoacidosis

A

a complication of diabetes that results from the severe lack of insulin

340
Q

elastography

A

a sonographic technique used to evaluate the stiffness of a mass or tissue

341
Q

ergonomics

A

the scientific study of creating tools and using equipment effectively in order to help the human body adjust to the work environment

342
Q

fusion imaging / hybrid imaging

A

technology that provides the ability to view alternate imaging modality (CT / MRI) during real time sonography

343
Q

Health Insurance Portability and Accountability Act

A

US law which upholds patient confidentiality and requires the use of electronic medical records

344
Q

hyperglycemic hypersmolar nonketotic syndrome

A

a diabetic syndrome characteristics by excessive urination and dehydration

345
Q

intravascular U/S

A

the technique that employs a miniature U/S transducer placed on a catheter and inserted into the circulatory system

346
Q

mechanical index

A

the calculation used to identify the likelihood into the circulatory system

347
Q

nonsocomial infection

A

a hospital - acquired infection

348
Q

radiation forces

A

forces exerted by a sound beam on an absorber or reflector that can alter structures

349
Q

shear wave elastography

A

elastography technique that uses shear wave information to analyze the stiffness of tissue

350
Q

shock

A

the body’s pathologic response to illness, trauma, or severe physiologic or emotional stress

351
Q

strain elastrography

A

operator dependent type of elastography that measure the change in tissue as a result of compression

352
Q

streaming

A

when acoustic fields cause motion of fluids

353
Q

thermal index

A

the calculation used to predict the maximum temperature elevation in tissues as a result of the attenuation of sound

AN SPI VOCAB (7 decks)

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