Physics Final Kremkau Vocabulary Flashcards
(273 cards)
1
Q
Mode of operation in which the display presents echo amplitude versus depth (used in opthamology)
A
A mode
2
Q
conversion of sound to heat
A
absorption
3
Q
having to do with sound
A
acoustic
4
Q
pressure, density, and particle vibration; sound wave quantities that vary in space and time
A
acoustic variables
5
Q
as low as reasonably achievable. The principle that is prudent to obtain diagnostic information with the least amount possible of energy exposure to the patient
A
ALARA
6
Q
Improper doppler-shift information from a pulsed spectral-Doppler or color-Doppler instrument when the true Doppler shift exceeds one-half the pulse repetition frequency
A
aliasing
7
Q
the process by which small voltages are increased to larger ones
A
amplification
8
Q
a device that accomplishes amplification
A
amplifier
9
Q
maximum variation of an acoustic variable or voltage
A
amplitude
10
Q
related to a procedure or system in which data are represented by proportional, continuously variable, physical quantities
A
analog
11
Q
a device that converts voltage amplitude to a number. Abbreviated ADC
A
analog to digital converter
12
Q
echo free
A
anechoic
13
Q
size of a transducer element (for a single element transducer) or group of elements (for an array)
A
aperture
14
Q
nonuniform driving of elements in an array to reduce grating lobes
A
apodization
15
Q
a transducer assembly containing several piezoelectric elements
A
array
16
Q
decrease in amplitude and intensity with distance as a wave travels through a medium
A
attenuation
17
Q
attenuation per centimeter of wave travel
A
attenuation coefficient
18
Q
A rapid technique, used in most Color-Doppler instruments, to obtain mean Doppler-shift frequency
A
autocorrelation
19
Q
in the direction of the transducer axis (sound travel direction)
A
axial
20
Q
the minimum reflector separation along the sound path that is required to produce separate echoes
A
axial resolution
21
Q
Mode of operation in which the display presents a spot of appropriate brightness for each echo received by the transducer
A
B mode
22
Q
a B-mode image that represents an anatomic cross section through the scanning plane
A
B scan
23
Q
sound scattered back in the direction from which it originally came
A
backscatter
24
Q
range of frequencies contained in an ultrasound pulse; range of frequencies within which a material, device, or system can operate
A
bandwidth
25
movement of the zero Doppler-shift frequency or zero flow speed line up or down on a spectral display
baseline shift
26
region containing continuous wave sound; region through which a sound pulse propagates
beam
27
the part of an instrument that accomplishes electronic beam scanning, apodization, steering, focusing, and aperture with arrays
beam former
28
pressure reduction in a region of high-flow speed
Bernoulli effect
29
indicating Doppler instruments capable of distinguishing between positive and negative Doppler shifts (approaching and receding flow)
bidirectional
30
having two possible states
bistable
31
binary digit; one or zero
bit
32
production and dynamics of bubbles in sound
cavitation
33
a single one- or two-way path for transmitting electric signals, in distinction from other parellel paths; an independent transmission delay line and transducer element path; an independent reception transducer element, amplifier, analong-to-digital converter, and delay line path
channel
34
sequential display of all the frames stored in memory at a controllable frame rate
cine loop
35
noise in the Doppler signal that generally is caused by high-amplitude, Doppler-shifted echoes from the heart or vessel walls
clutter
36
capacative micromachined ultrasonic transducer that contains miniature elements that are comprised of two electrically conducting layers facing each other; one of which is fixed and the other of which is a flexible membrane
CMUT
37
a sophisticated form of transmission in which the driving voltage pulses have intrapulse variations in amplitude, frequency, and/or phase.
coded excitation
38
the presentation of two-dimensional, real-time Doppler-shift information in color superimposed on a real-time, gray-scale, anatomic, cross-sectional image. Flow directions toward and away from the transducer are presented as different colors on the display
color-Doppler display
39
a series of closely spaced reverberation echoes
comet tail
40
equalization of received echo amplitude differences caused by different attenuations for different reflector depths; also called depth gain compensation or time gain compensation
compensation
41
distensibility; nonrigid stretchability of vessels
compliance
42
combination of a piezoelectric ceramic and a nonpiezoelectric polymer
composite
43
reduction in differences between small and large amplitudes. Region of high density and pressure in a compressional wave
compression
44
combination of positive or negative pressures
constructive interference
45
a wave in which cycles repeat indefinitely; not pulsed. Abbreviated CW
continuous wave
46
A Doppler device or procedure that uses continuous wave ultrasound
continuous wave doppler
47
a suspension of bubbles or particles introduced into circulation to enhance the contrast between anatomic structures, thereby improving their imaging
contrast agen
48
ability of a gray-scale display to distinguish between echoes of slightly different intensities
contrast resolution
49
curved linear array
convex array
50
the cosine of angle A is the length of side b divided by the length of side c. abbreviated cos
cosine
51
a gel used to provide a good sound path between a transducer and the skin by eliminating the air between the two
coupling medium
52
the Reynolds number above which turbulence occurs
critical Reynolds number
53
leakage of strong signals in one direction channel of a Doppler receiver into the other channel; can produce the spectral-Doppler mirror-image artifact
cross-talk
54
element
crystal
55
temperature at which an element material loses its piezoelectric properties
curie point
56
one complete variation of an acoustic variable
cycle
57
material attached to the rear face of a transducer element to reduce pulse duration; the process of pulse duration reduction
damping
58
unit of power or intensity ratio; the number of decibels is 10 times the logarithm (to the base of 10) of the power or intensity ratio. Abbreviated dB.
decibel
59
detection
demodulation
60
mass divided by volume
density
61
combination of positiver and negative pressures
destructive interference
62
the ability to image fine detail and to distinguish closely spaced reflectors
detail resolution
63
conversion of voltage pulses from radio frequency to video form
detection
64
related to a procedure or system in which data are represented by numeric digits
digital
65
a device that converts a number to a proportional voltage amplitude. Abbreviated DAC.
digital-to-analog converter
66
a thin, flat, circular object
disk
67
a device that presents a visual image derived from voltages received from an image processor
display
68
flow that cannot be described by straight, parallel streamlines
disturbed flow
69
the angle between the sound beam and the flow direction
Doppler angle
70
a change in frequency caused by reflector motion
Doppler effect
71
the mathematical description of the relationship between the Doppler shift, frequency, Doppler angle, propagation speed, and reflector speed
Doppler equation
72
color-doppler display in which colors are assigned according to the strength (amplitude, power, intensity, energy) of the Doppler-shifted echoes
Doppler-power display
73
reflected frequency minus incident frequency; the change in frequency caused by motion
Doppler shift
74
the range of frequencies present in Doppler-shifted echoes
Doppler spectrum
75
an ultrasound instrument that combines gray-scale sonography with pulsed Doppler and, possibly, continuous wave Doppler
duplex instrument
76
fraction of time that pulsed ultrasound is on
duty factor
77
aperture that increases with increasing focal length (to maintain constant focal width)
dynamic aperture
78
continuously variable reception focusing that follows the increasing depth of the transmitted pulse as it travels
dynamic focusing
79
ratio (in decibels) of largest to smallest power that a system can handle; ratio of the largest to smallest intensity of echoes encountered
dynamic range
80
reflection
echo
81
regions of circular flow patterns present in turbulence
eddies
82
imaging tissue stiffness by tracking movement under mechanical stress
elastography
83
the piezoelectric component of a transducer assembly
element
84
the detail resolution in the direction perpendicular to the scan plane. It is equal to the section thickness and is the source of section thickness artifact
elevational resolution
85
capability of doing work
energy
86
increase in echo amplitude from reflectors that lie behind a weakly attenuating structure
enhancement
87
number of pulses used to generate one color-Doppler image scan line
ensemble length
88
the region of a sound beam in which the beam diameter increases as the distance from the transducer increases
far zone
89
digital computer implementation of the Fourier transform
fast Fourier transform
90
an electric circuit that passes frequencies within a defined range
filter
91
a backlighted rectangular matrix of thousands of liquid-crystal display elements
flat-panel display
92
to move in a stream; volume flow rate
flow
93
a material that flows and conforms to the shape of its container;a gas or liquid
fluid
94
distance from a focused transducer to the center of a focal region or to the location of the spatial peak intensity
focal length
95
region of minimum beam diameter and area
focal region
96
length of the focal region
focal zone
97
the concentration of the sound beam into a smaller beam area than would exist otherwise
focus
98
a mathematical technique for obtaining a Doppler frequency spectrum
Fourier transform
99
bandwidth divided by operating frequency
fractional bandwidth
100
a single image produced by one complete scan of the sound bream
frame
101
number of frames of echo information stored each second
frame rate
102
far zone
Fraunhofer zone
103
constant display of one of the frames in memory
freeze
104
number of cycles per second
frequency
105
the range of Doppler-shift frequencies present in the returning echoes
frequency spectrum
106
near zone
fresnel zone
107
the primary frequency in a collection of frequencies that can include odd and even harmonics and subharmonics
fundamental frequency
108
ratio (in decibels) of amplifier output to input electric power
gain
109
a device that allows only echoes from a selected depth (arrival time) to pass
gate
110
an electronic device that rapidly performs calculations to accelerate the creation of images
graphics processing unit (GPU)
111
additional weaker beams of sound traveling out in directions different from the primary beam as a result of the multielement structure of transducer arrays
grating lobes
112
range of brightness (gray levels) between white and black
gray scale
113
frequencies that are even and odd multiples of another, commonly called fundamental or operating frequency
harmonics
114
unit of frequency, one cycle per second; unit of pulse repetition frequency, one pulse per second
hertz
115
the color perceived based on the frequency of light
hue
116
a small transducer element mounted on the end of a narrow tube; a piezoelectric membrane with small metallic electrodes
hydrophone
117
having relatively weak echoes. Opposite of hyperechoic (having relatively strong echoes)
hypoechoic
118
a reproduction, representation, or imitation of the physical form of a person or a thing
image
119
the portion of a system operating on Principle 2 that acquires the echo information from the signal processor, performs the retrospective, virtual-beam computations and sends the results to the display.
image former
120
the part of the image processor where echo information is stored in image format
image memory
121
an electronic device that manipulates and prepares images for visual presentation
image processor
122
density multiplied by the sound propagation speed
impedance
123
angle between incident sound direction and a line perpendicular to the boundary of a medium
incidence angle
124
resistance to acceleration
inertia
125
an electronic system that electrically drives a transducer, receives returning echoes, and presents them on a visual display as an anatomic image, Doppler spectrum, or color-Doppler presentation
instrument
126
power divided by area
intensity
127
reflected intensity divided by incident intensity; the fraction of incident intensity transmitted into the second medium
intensity reflection coefficient
128
transmitted intensity divided by incident intensity; the fraction of incident intensity transmitted into the second medium
intensity transmission coefficient
129
combinations of positive and/or negative pressures
interference
130
one thousand hertz
kilohertz
131
flow in which fluid layers slide over each other in a smooth, orderly manner, with no mixing between layers
laminar flow
132
perpendicular to the direction of sound travel
lateral
133
gain controls that enable different gain values to be applied laterally across an image to compensate for differing attenuation values in different anatomic regions
lateral gain control
134
minimum reflector separation perpendicular to the sound path that is required to produce separate echoes
lateral resolution
135
a ceramic piezoelectric material
lead zirconate titanate
136
a curved material that focuses a sound or light beam
lens
137
adjectival form of line
linear
138
array made of rectangular elements arranged in a straight line
linear array
139
an anatomic image presented in a rectangular format
linear image
140
linear array operated by applying voltage pulses to all elements, but with small time differences (phasing) to direct ultrasound pulses out in various directions
linear phased array
141
linear array operated by applying voltage pulses to groups of elements sequentially
linear sequenced array
142
wave in which the particle motion is parellel tot he direction of wave travel (compressional wave)
longitudinal wave
143
brightness of a presented hue and saturation
luminance
144
A B-mode presentation of changing reflector position (motion) versus time (used in echocardiography)
M mode
145
measure of the resistance of an object to acceleration
mass
146
material attached to the front face of a transducer element to reduce the reflections at the transducer surface
matching layer
147
an indicator of nonthermal mechanism activity; equal to the peak rarefactional pressure divided by the square root of the center frequency of the pulse bandwidth
mechanical index
148
material through which a wave travels
medium
149
one million hertz
megahertz
150
an artifactual gray-scale, color flow, or Doppler signal appearing on the opposite side of a strong reflector
mirror image
151
several reflections produced by a pulse encountering a pair of reflectors; reverberation
multiple reflection
152
the narrowing of a sound beam that occurs with an unfocused flat transducer element
natural focus
153
the region of a sound beam in which the beam diameter decreases as the distance from the transducer increases
near zone
154
sound propagation in which the propagation speed depends on pressure causing the wave shape to change and harmonics to be generated
nonlinear propagation
155
the Doppler-shift frequency above which aliasing occurs; one-half of the pulse repetition frequency
Nyquist limit
156
sound direction that is not perpendicular to media boundaries
oblique incidence
157
preferred frequency of operation of a transducer
operating frequency
158
in operating principle 1, positional information is determined by knowledge of the direction of the pulse when it enters the patient and by measurment of the time it takes for each echo to return to the transducer. The proper location to present the echo can then be determined from a starting point on the display (usually at the top). With knowledge of the sound speed, the instrument uses the echo arrival time to determine the depth of the structure that produced that echo
Operating Principle 1
159
Operating principle 2 sends several pulses of ultrasound through the cross section of anatomy to be imaged but does not produce a one-for-one correspondence of pulse and displayed scan line. Instead, all the echo information from throughout the anatomic cross section is collected, and then massive computational processes determine the location and strength of each echo produced at each location in the anatomy. This approach is used in recent, sophisticated instruments and produces improved quality compared with Principle 1.
Operating Principle 2
160
the extension of the field of view beyond the normal limits of a transducer scan plane
panoramic imaging
161
laminar flow with a profile in the shape of a parabola
parabolic flow
162
imaging depth
penetration
163
time per cycle
period
164
geometrically related by 90 degrees
perpendicular
165
sound direction that is perpendicular to the boundary between media
perpendicular incidence
166
averaging sequential frames together
persistence
167
tissue-equivalent device that has characteristics that are representative of tissues
phantom
168
a description of progress through a cycle; one full cycle is divided into 360 degrees of phase
phase
169
two signals differing by one-fourth of a cycle
phase quadrature
170
an array that steers and focuses the beam electronically (with short time delays)
phased array
171
linear sequenced array with phased focusing added; linear sequenced array with phased steering of pulses to produce a parallelogram-shaped display
phased linear array
172
the system provides means for electronically communicating images and associated information to workstations and devices external to the sonographic instrument, the examining room, and even the building in whcih the scanning in done
picture archiving and communications system
173
conversion of pressure to electric voltage
piezoelectricity
174
picture element; the unit into which imaging information is divided for storage and display in a digital instrument
pixel
175
flow with all fluid portions traveling with the same flow speed and direction
plug flow
176
unit of viscosity
poise
177
the mathematical description of the dependence of volume flow rate on pressure, vessel length and radius, and fluid viscosity
Poiseuille equation
178
imaging processing done after storage in the memory
postprocessing
179
rate at which work is done; rate at which energy is transferred
power
180
signal and image processing accomplished before storage in the memory
preprocessing
181
force divided by the area in a fluid
pressure
182
the gray-scale echo strength below which color-Doppler information is shown preferentially on a display
priority
183
transducer assembly
probe
184
progession or travel
propagation
185
speed at which a wave moves through a medium
propagation speed
186
flow that accelerates and decelerates with each cardiac cycle
pulsatile flow
187
a description of the relationship between peak systolic and end diastolic flow speeds of Doppler shifts
pulsatility index
188
a brief excursion of a quantity from its normal value; a few cycles
pulse
189
interval of time from beginning to the end of a pulse
pulse duration
190
number of pulses per second
pulse-repetition frequency
191
interval of time from the beginning of one pulse to the beginning of the next
pulse repetition period
192
a Doppler device or procedure that uses pulsed-wave ultrasound
pulsed Doppler
193
ultrasound produced in pulsed form by applying electric pulses or voltages of one or a few cycles to the transducer
pulsed ultrasound
194
ultrasound imaging in which pulses are reflected and used to produce a display
pulse-echo technique
195
the force exerted by a sound beam on an absorber or a reflector
radiation force
196
voltages representing echoes in cyclic form
radio frequency
197
an artifact produced when echoes are placed too close to the transducer because a second pulse was emitted before they were received from the first pulse
range ambiguity
198
relationship between round-trip pulse travel time, propagation speed, and distance to a reflector
range equation
199
selection of the depth from which echoes are accepted based on echo arrival time
range gating
200
region of low density and pressure in a compressional wave
rarefaction
201
unit of impedance
rayl
202
imaging with a rapid frame sequence display
real time
203
a display that, with a sufficient frame rate, appears to image moving structures or a changing scan plane continuously
real-time display
204
portion of sound returned from a media boundary; echo
reflection
205
angle between the reflected sound direction and a line perpendicular to the media boundary
reflection angle
206
media boundary that produced a reflection; reflecting surface
reflector
207
change of sound direction on passing from one medium to another
refraction
208
the number of times each second that information is sent from the image memory to the display. The number of times per second that a computer monitor redraws the information found in the memory
refresh rate
209
pressure difference divided by volume flow rate for steady flow
resistance
210
the ability to distinguish echoes in terms of space, time, or strength
resolution
211
the condition in which a driven mechanical vibration is of a frequency similar to a natural vibration frequency of the structure, yielding maximum response
resonance
212
operating frequency
resonance frequency
213
multiple reflection
reverberation
214
a number that depends on flow speed and viscosity to predict the onset of turbulence
Reynolds number
215
the anatomic region from which pulsed Doppler echoes are accepted
sample volume
216
the amount of hue present in a mix with white
saturation
217
a line produced on a display that represents ultrasonic echoes returning from the body. A sonographic image is composed of many such lines
scan line
218
transducer assembly
scanhead
219
the sweeping of a sound beam through the anatomy to produce an image
scanning
220
an object that scatters sound in many directions because of its small size or fits surface roughness
scatterer
221
diffusion or redirection of sound in several directions upon encountering a particle suspension or a rough surface
scattering
222
a geometric figure bounded by two radii and the arc of the circle included between them
sector
223
an anatomic image presented in a pie slice- shaped format
sector image
224
ability of an imaging system to detect weak echoes
sensitivity
225
reduction in echo amplitude from reflectors that lie behind a strongly reflecting or attenuating structure
shadowing
226
weaker beams of sound traveling out from a single element in directions different from those of the primary beam
side lobes
227
information-bearing voltages in an electric circuit; an acoustic, visual, electric, or other conveyance of information. The physical representation of a message or information
signal
228
an electronic device that manipulates electric signals in preparation for appropriate presentation of information contained in them
signal processor
229
thickness of the scanned tissue volume perpendicular to the scan plane
slice thickness
230
medical two-dimensional, cross-sectional, and three-dimensional anatomic and flow imaging using ultrasound
sonography
231
traveling wave of acoustic variables
sound
232
the region of a medium that contains virtually all of the sound produced by a transducer
sound beam
233
an emitter of ultrasound; transdcuer
source
234
averaging of frames that view the anatomy from different angles
spatial compounding
235
length of space over which a pulse occurs
spatial pulse length
236
the granular appearance of images and spectral displays that is caused by the interference of echoes from the distribution of scatterers in tissue
speckle
237
separation of frequencies in a Doppler signal for display as a Doppler spectrum; the application of the Fourier transform to determine the frequency components present in a Doppler signal
spectral analysis
238
the widening of the Doppler-shift spectrum; that is, the increase in the range of Doppler-shift frequencies present that occurs because of a broadened range flow velocities encountered by the sound beam. This occurs for disturbed and turbulent flow
spectral broadening
239
the presentation of Doppler-information in a quantitative form of Doppler shift versus time. Visual display of a Doppler spectrum
spectral-Doppler display
240
a device that derives a frequency spectrum from a complex signal
spectrum analyzer
241
reflection from a large, flat, smooth boundary
specular reflection
242
propagation speed that is different from the assumed value
speed error
243
narrowing of a vessel lumen
stenosis
244
property of a medium; applied pressure divided by the fractional volume change produced by the pressure
stiffness
245
the increase or decreaseof the length of a segment of a material, subjected to a stress, divided by its original length
strain
246
a line representing the path of a motion of a particle of fluid
streamline
247
nonspecific term referring hear to amplitude or intensity
strength
248
a force per unit area applied to a material that compresses or stretches it
stress
249
ability to distinguish closely spaced events in time; improves with increased frame rate
temporal resolution
250
a device without tissue-like properties that is designed to measure some characteristic of an imaging system
test object
251
an indicator of thermal mechanism activity (estimated temperature rise); a value equal to transducer acoustic output power divided by the estimated power required to raise tissue temperature by 1 degree celcius
thermal index
252
equalization of echo amplitude differences caused by different attenuations for different reflector depths
time gain compensation
253
a device that converts energy from one form to antoher
transducer
254
transducer element(s) with damping and matching materials assembled in a case
transducer assembly
255
angle between the transmitted sound direction and a line perpendicular to the media boundary
transmission angle
256
a sound wave in which the particle motion is perpedicular to the direction of wave travel, also called a shear wave
transverse wave
257
random, chaotic, multidirectional flow of a fluid with mixing between layers; flow that is not laminar
turbulence
258
sound having a frequency greater than what humans can hear, that is, greater than 20 kHz
ultrasound
259
a device that converts electric energy to ultrasound energy, and vice versa
ultrasound transducer
260
square of standard deviation; one of the outputs of the autocorrelation process; a measure of spectral broadening
variance
261
linear sequenced array that emits pulses from different starting points and (by phasing) in different directions
vector array
262
an imaginary beam that describes the result of retrospective, computed beam forming. The virtual beam can be imagined in transmission or reception form
virtual beam
263
an imaginary reception beam that can be thought of as determine the echo produced at each pixel location in the image
virtual reception beam
264
an imaginary laser-thin transmitted ultrasound beam that can be thought of as producing the excellent detail resolution throughout the image that is accomplished with retrospective, computed beam forming
virtual transmission beam
265
resistance of a fluid to flow
viscosity
266
three-dimensional imaging
volume imaging
267
volume of fluid passing a point per unit of time
volumetric flow rate
268
an electric filter that passes frequencies above a set level and eliminates strong, low-frequency Doppler shifts from pulsating heart or vessel walls or tissue motion
wall filter
269
traveling variation of one or more quantities
wave
270
length of space over which a cycle occurs
wavelength
271
an anechoic region appearing beneath echo frequencies presented on a Doppler spectral display
window
272
a measure of the hardness (stiffness) of a material. It is the ratio of the applied stress to the resulting strain in a material subjected to the stress
Young's modulus
273
an analog detector that yields mean Doppler shift as a function of time
zero-crossing detector
