Definitions Flashcards
1
Q
SOUND: All waves carry ______ from one location to another
A
Energy
2
Q
Acoustic propagation properties
the effects of the _____ upon the sound wave
A
MEDIUM
3
Q
Compressions: areas of _______ pressure/density
Rarefactions: areas of _______ pressure/density
A
Compressions= INCREASED
Rarefactions= DECREASED
4
Q
Sound= __________, longitudinal wave
A
MECHANICAL
5
Q
Sound travels in a _______ line
A
STRAIGHT
6
Q
List the 3 Acoustic variables
A
PRESSURE, DENSITY, DISTANCE
7
Q
Transverse wave= particles move in a ___________ direction
Longitudinal wave= Particles move ____and _______ in the ______ direction
A
Perpendicular= transverse
Back & forth, Same direction= longitudinal
8
Q
Acoustic parameters= describe the _______ of a particular sound wave
A
Features
9
Q
Period= the time required to complete a ______ cycle
A
Single
UNCHANGED
10
Q
Frequency= number of certain _____ that occur in a particular time duration
-UNCHANGED
A
Events
11
Q
Audible sound is between __ Hz to 20,000 Hz yes heard
Ultrasound= greater than
Infrasound = less than 20 Hz; frequency too low
A
20
12
Q
List the 3 bigness parameters (can be changed)
A
Power, Amplitude, Intensity
PAI
13
Q
Amplitude= the difference between the average value and the ________ value of the acoustic variable
DB
A
Maximum value
14
Q
Power= the _____ work is performed. Rate of energy transfer.
-Watts
-Sound source
-decreases as sound travels
-changed
Power is proportional to the waves amplitude squared
A
Rate
15
Q
When the amplitude is tripled, the power is increased by the factor of _____
3x3=
A
9
16
Q
When the amplitude is halved, power is decreased by a factor of _____
A
4 ; quartered !
17
Q
When the amplitude is doubled, power is increased by a factor of
A
4; quadrupled
2x2=4
18
Q
Intensity= the __________ of energy in a sound beam.
Beams power divided by area
INTENSITY= Power/Beam Area
Watts/cm2
Changed
Intensity is a key parameter for _____
Intensity is NOT UNIFORM across a sound beam
A
Concentration
Bioeffects
19
Q
Wavelength= _______ or distance of a single cycle.
-mm
-BOTH MEDIUM/SOURCE
-UNCHANGED
0.1-0.8
WAVELENGTH= SPEED/FREQUENCY
L=C/F
A
LENGTH
20
Q
Higher frequency= ________ wavelength
Lower frequency = ________ wavelength
A
Higher= Shorter
Lower= Longer
21
Q
Speed= rate that sound travels through medium
-mm/us
-MEDIUM ONLY
-UNCHANGED
1,540
Sound = slow medium= ____ wavelength
Sound = fast medium= ________ wavelength
A
Slow= short
Fast = long
22
Q
Gas is _______
Solid is ______
A
Gas = slower
Solid= faster
23
Q
Air 330 =
A
Slowest
24
Q
Bone= 2,000-40000
A
Fastest
25
Stiffness and speed = _____ direction
-bulk modulus
Density and speed= _____ direction
-compressibility/elasticity
Stiffness = same
Density = opposite
26
Interference= _____ waves overlap at the same location, and at the same time and combine into a single new wave
Two waves
27
Constructive interference (IN-PHASE) = amplitude of the new, combined wave is _________ then the original two waves.
Deconstructive interference(OUT-OF-PHASE) = amplitude of the new wave is _____than original wave
GREATER
Less than
28
In diagnostic imaging, short _____ acoustic energy are required to create an atomic images
CW CANNOT CREATE IMAGES!
A pulse= collection of cycles that travel together
Pulses
29
Pulse duration= start of one pulse to the end of that pulse
-“______” time/TALKING TIME
-time
-sound source
PD= PERIOD x # of cycles
-UNCHANGED
2-4 cycles
Actual time
30
SPL= spatial pulse length= distance or _____ from start to the end of one pulse
-PD& SPL= directly related
-BOTH MEDIUM/SOURCE
-UNCHANGED
-SPL affects _______ resolution
Shorter pulses= ______ quality images
SPL= WAVELENGTH X # OF CYCLES
Length
Axial resolution
Higher quality
31
PRP= time from the START of one pulse to the START of the NEXT pulse.
-listening time
-PRP & depth= directly related
-CHANGED
-PRP is determined by_____
Depth
32
PRF= number of _____ created by the system in one second
-Hz
-SOURCE
-CHANGED
-PRF& DF= directly related ++
PRF &PRP= INVERSELY R (-)(+)
-PRF determined by_____
-PRF IS NOT RELATED TO ______
Pulses
Depth
Not related to Frequency
33
Shallow image = _____ PRF
Deeper image= ______ PRF
Higher
Lower
34
Duty factor = ________ or fraction of time that the system transmits sound
-UNITLESS
-SOURCE
-CHANGED
-small value, less than ____%
CW= 100%
Little talking, lots of _______
Percentage
1%
Lots talking
35
Shallow image= ______ DF
DEEEPER IMAGE=_____ DF
Higher
Lower
36
Spatial: an ultrasound team does not have the same intensity at different ________ within the beam
-DISTANCE/SPACE
LOCATION
37
Temporal= pulsed ultrasound does not have same intensity at different ________
ALL TIME
TIMES
38
SPTP= ________ value
SATA= _____ value
SPTA= ______
Highest
Lowest
Bio effects
39
3dB= ____ bigger
-3dB= ______
One quarter=
2x
One half
-6dB
40
The relative change in a sound beams intensity is measured in
dB
41
Attenuation= DECREASE in ______ of sound wave
The further sound travels, the ____ attenuation
SPEED & ATTENUATION = ______!
STRENGTH
MORE
Unrelated
42
List the 3 components of Attenuation
1. Absorption-most important
2. Scattering
3. Reflection
43
Less attenuation =
_____ distance
_____ frequency
Less A= shorter D, lower F
44
More attenuation=
______ distance
______ frequency
Longer distance
Higher frequency
45
Air is much much ____ attenuation than in soft tissue
AIR=MORE
46
Lung & bone= _____ than soft tissue
More
47
Water is much much _____ than in soft tissue
Water= Less
48
In soft tissue, LOWER frequency = _____attenuation
-PENETRATE FURTHER
Less
49
T/F?
Air>>>Bone & lung>> soft tissue>> water
True
50
REFLECTION: occurs when propagating sound energy STRIKES a boundary between two media and _____ returns to the transducer
Some
51
SPECULAR reflection: reflections from a _______ reflector (MIRROR) & return in _____ direction
-wavelength is much smaller
Strikes boundary at 90 degrees
-VESSEL WALL
SPECULAR = SMOOTH mirror
52
Strongest reflections are produced ______ incidence -90 degrees
Strongest = NORMAL incidence
53
DIFFUSE/Backscatter= reflection of sound generally back towards the transducer, but in ______ directions
-disorganized
-ROUGH BOUNDARY
-Same size as wavelength
Multiple directions
54
Scattering: RANDOM
_____ frequency = more scatter
Higher frequency = more scatter
55
Rayleigh Scattering: ______
Scatter
56
Attenuation coefficient= ONE-HALF THE FREQUENCY
0.5db/cm/MHz
Remains the same no matter how far
Frequency & attenuation coefficient= _______ related
DIRECTLY RELATED
57
IMPEDANCE number associated with a _______
-RAYLS= Z
-CALCULATED/not measured
Impedance = DENSITY x SPEED
MEDIUM
58
Incident intensity= intensity of a sound wave, _____ to striking a boundary
Reflected intensity= ________ striking a boundary, changes direction, and returns back from where it came
Transmitted intensity= after striking a boundary, continues on in the same general direction that it was originally traveling
Incident intensity = reflected, intensity + transmit it, intensity
Before= incident
AFTER striking = reflected
59
Intensity, reflection, coefficient IRC= ________ the intensity that bounces ______ when the sound strikes a boundary
Intensity, transmission coefficient ITC= ________ of the incident intensity, that, ______ striking a boundary, continues on the same general direction
IRC + ITC= 100%
IRC= Percentage ; bounces back
ITC= percentage; after
60
Snell’s Law= describes the physics of _________
Refraction
61
REFRACTION= transmission with a ______ (like Beckham)
-________ in direction as sound transmits from one medium to another
Requires:
________ incidence
_________ speeds
BEND
Transmits
-oblique incidence
-Different speeds
62
Time-of-flight= time needed for a pulse to travel to, and from the transducer in the reflector
When time of flight is measured, we can determine reflector _____
Depth
63
13 microsecond rule = every 13 us of go-return time means reflector is __cm deeper in body
1 cm
64
Piezoelectric effect= property of certain materials to create a _______ when PRESSURE IS APPLIED or when material is mechanically _______.
-change shape
VOLTAGE
DEFORMED
65
Piezoelectric materials:
Synthetic = PTZ= lead ______ titanate
Natural= quartz, tourmaline
Zirconate
66
Curie temperature = PZT heated 360-680
-PZT is _________
DESTROYED
PZT IS DEPOLARIZED
67
Active element=
-CERAMIC, PZT, CRYSTAL
it is ____ wavelength THICK
Active element = 1/2 wavelength THICK
68
Case= protects the _______ components from damage and insulates the patient from electrical shock
Internal
69
Matching layer= IMPEDANCE between those of the SKIN and the ACTIVE ELEMENT _________ transmission between the active element and skin.
________ wavelength thick
INCREASE
Matching layer = ONE-Quarter wavelength thick
70
Damping/Backing material= REDUCES “________”
Material is bonded to active element
Short pulses create more accurate images
Made from :
Continuous wave transducers do not require damping material
Damping= reduce RINGING
Epoxy resin
71
Bandwidth = RANGE of _______
between the highest and lowest frequency emitted from the transducer
Imaging probes are _____ bandwidth or broadband
FREQUENCIES, WIDE
72
Quality factor= ______ number related to DAMPING
Low-Q= ______ & _____ bandwidth (imaging pulsed transducers)
High-Q= _______ & ______ bandwidth (CW & therapeutic transducers)
UNITLESS number
LOW Q= DAMPING/WIDE
HIGH Q= NO DAMPING/ NARROW
73
CW transducers:
sound frequency= ______ frequency
Electrical frequency
74
Pulsed transducers:
the main or ______ frequency of sound from a pulsed transducers, determined by two characteristics of the Crystal:
1.
2.
Higher frequency =
____ crystal
____ PZT
Lower Frequency =
____ crystal
____ PZT
Pulsed transducers
Center
1. THICKNESS
2. SPEED of PZT material
High F=
THIN crystal
FAST PZT
LOW frequency=
THICK
SLOW PZT
75
Beam width= as sound travels width of beam changes
-starts out SAME SIZE as transducer _____ or APERTURE
-gets ______ until it reaches smallest diameter then beam diverges
Diameter
Narrower
76
______ beams create better images 😊
NARROW BEAMS= 😊
77
Focus/focal point= location where the beam reaches its ________ diameter
Minimum
78
Focal depth/near zone length=
__________ from the transducer to the focus
DISTANCE
79
Near zone/FRESNEL = region in between the transducer and the _______.
-sound beams _______ in the near zone
Far zone/FRAUNHOFER=
region, deeper than the focus, ________ the Near field
-Sound beams
________ in far zone
FOCUS; CONVERGE
Beyond, DIVERGE
80
At transducer= ______ as transducer aperture
SAME
81
At END of Near zone= ____ of transducer aperture
1/2
82
At 2 near zone lengths = _____ as transducer aperture
SAME
83
Deeper than 2 near zones= ______ than transducer aperture
GREATER
84
PZT diameter = transducer _______
Aperture
85
Focal depth determined by two factors
1. Transducer diameter/aperture
2. Frequency.
86
Shallow focus= ________ diameter, ____ frequency
Deep focus= ______ diameter, _____ frequency
Small, low
Large, high
87
Sound beam divergence= _____ of the sound beam in the deep FAR ZONE
SPREAD
88
Less divergence=
_______ diameter active element
_______ frequency
_______ beam in far field
_______ Lateral resolution
Less Divergence =
Large d
High frequency
Narrow
Improved lateral
89
More divergence =
_______ diameter active element
_______ frequency
_______ beam in far field
_______ Lateral resolution
More divergence =
SMALL D
LOW FREQ
WIDE BEAM
DEGRADED LATERAL
90
Diffraction pattern= __-shaped also called ________ wavelet. When produced by a _____ source, with a size near the wave length of the sound, waves will diverge in the shape as they propagate.
Diffraction = V-SHAPED
HUYGENS WAVELET
91
Huygens’s Principle= _______ shape
-tiny sound source
Result of ________ & destructive interference
Hourglass shape
Constructive
92
Resolution = ability to image ________
Accurately
93
Axial resolution= ability to distinguish two structures that are close to each other, _____to _____, PARALLEL to, or ALONG the beams main axis
Better axial resolution = ______ pulses
-UNCHANGED
mm,cm
AXIAL R= SPL/2
Front to back, parallel
SHORTER PULSES
94
Less ringing means ______ cycles
Fewer cycles
95
Higher frequency means ______ wavelengths
Shorter
96
Axial resolution improves with
_____ ringing, fewer cycles
_______ frequency sound, shorter wavelengths
Axial resolution is best using transducers with the highest frequency and fewest numbers of cycle per pulse
Less ringing
Higher frequency
97
True or false
high frequency transducers create more accurate images.
As frequency increases, axial resolution decreases
True
98
Lateral resolution= the ________ distance that two structures are separated by _____-to_____ or PERPENDICULAR that produces two distinct echoes.
-distance
Lateral resolution ________ at deeper depth in the far zone
Better at near zone
Minimum
Side to side
Degrades
99
Lateral resolution= beam ______
Beam width variation
Point spread artifact
Diameter
100
T/F? LATERAL RESOLUTION is usually NOT AS GOOD as axial resolution because sound pulses are WIDER than they are short.
True
101
T/F? In the far field, HIGH FREQUENCY pulsed sound has NARROWER beams, compared to lower frequencies in the far Field.
True
102
______ frequency IMPROVES image detail
HIGH FREQUENCY
103
____ frequencies provide deeper penetration
LOW frequencies
104
Axial vs lateral
Yup
105
2D images may be referred to as “___-modes” since they are grey scale
2D=B-Mode
106
Mechanical scanning
-one disc shaped element (coin)
-moved by a ______
-oscillating crystal or mirror
-CONVENTIONAL/______ : curvature of PZT focuses beam at specific depth
-FAN SHAPED
-Scanline spread apart, creating ____ at greater depths
Motor
Fixed
Gaps
107
Transducer Arrays
collection of active elements in a ____transducer
Single
108
Linear switched
-Rectangular
-no steering
-_____ line dropout
Vertical
109
Phased arrays: adjustable focus or _____-focus
-_________ STEERED
-sector shaped
Phase delays
-steering can become erratic
Multi focus
Electronically steered
Poor steering
110
Contrast resolution= visualizing a ______ of gray shade in an image.
Few gray shades= _____ contrast resolution
many gray shades = ______ contrast resolution
VARIETY
Few gray= poor
Many gray = good
111
Spatial resolution= DETAIL
affected by _______ & __________ resolution, line ________
(3 things)
Fine detail= ______ spatial resolution
Limited detail= ______ spatial resolution
Axial, lateral, line density
Fine= good
Limited= bad
112
Real-time imaging= ______ 🎥
Series of frames displayed in rapid sequence to give the impression of constant motion
🎥
113
Temporal resolution= ability to accurately locate moving structures at any particular instant in time
Temporal resolution depends on _____ rate
20hz-100hz
Frame rate
114
Frame rate is determined by imaging ______ and # of _______ per image
Depth, pulses per image
115
Frame rate is limited to 2 factors:
1. ________ of sound
2. Imaging DEPTH
Speed
116
T/F: speed is a limitation of temporal resolution
True
117
4 settings to change temporal resolution:
1. # of pulses per scan line
2. _______ size
3. Maximum _____
4. Line ________
Sector size
Depth
Line Density
118
Temporal resolution improved=
-______ frames made each second
-_____ time to make image
-______ or fewer pulses
TP improved=
MORE FRAMES
LESS TIME
SHALLOWER
119
Temporal resolution degraded=
-______ frames made each second
-_____ time to make image
-______ or MORE pulses
LESS FRAMES
MORE TIME
DEEPER
120
T/F shallow depth makes frame faster
True
121
High temporal resolution =
________ frame rate
_________ imaging
_________ pulses per image
SINGLE focusing
________ sector
LOW LINE DENSITY
Better movie, lower quality image
High frame rate
Shallow imaging
Fewer pulses
Narrow sector
122
LOW temporal resolution =
________ frame rate
_________ imaging
_________ pulses per image
Multi-focusing
________ sector
HIGH LINE DENSITY
POOR movie, lower quality image
Low frame rate
DEEP imaging
More pulses
Wide sector
123
Tf and frame rate are _______
Tf x FR= 1
Reciprocals
124
Master synchronizer= communicates with ____ of the individual components of the ultrasound system.
Organizes, synchronizes and times their functions, so as to operate as a single integraded system
All
125
Pulser= controls the _______ signals sent to the act of elements for sound pulse generation
-determines the _____, PRF, pulse amplitude
-creates the _______ pattern for ______ array systems called the BEAM FORMER
Electrical signals
PRP
FIRING
PHASED ARRAY
126
Transducer converts electrical into _________ energy during transmission
Converts returning acoustic energy into ______ energy during reception
Acoustic energy
Electrical energy
127
Receiver:
128
Output, power
when output power is changed, the strength of every transmitted pulse to the ______ changes
-can be changed
-impacts brightness of entire image
Low output power= ______ image
High output power= BRIGHTER IMAGE
Body
Low = darker image
129
Signal-to-noise ratio
Signal= meaningful portion of the data = 😊👍
Noise= 😡 inaccurate
High signal to noise ratio= _____ quality image; stronger signal 😊
Low signal to noise ratio= _____ quality image; NOISE is stronger 😡
High quality
Low quality
130
T/F: increasing output, power is the primary way to improve signal to noise ratio
True
131
Receiver: boosts the ________ of these signals, processes them, and prepares them for display
TGC, gain, reject, dynamic range
Strength
132
Gain: _________ the strength of all electrical signals in the receiver BEFORE further processing.
-adjusted
-db
-changes brightness 🔅 of entire image! Uniform; identical
Preamplifier alters gain _____ gain is applied
Increases strength
Before
133
Compensation or TGC= used to create _______ BRIGHTNESS 🔆 from ____ to bottom!
Compensation treats echoes differently, depending upon the depth that which they arise
-Compensation makes an image ______ bright at ALL depths
Higher frequency = ____ compensation because it attenuates more
Low frequency = ______ compensation because it attenuated less
UNIFORM BRIGHTNESS 🔅
TOP TO BOTTOM
Equally
High frequency = more c
Low frequency = less c
134
Dynamic range= adjust the grayscale range within the image. Allows us to see _____ gray shades and different tissues.
-changes gray scale ______
-adjusted
All
Mapping
135
Reject= displays ____ level echoes
Eliminates ____level noise!
-only affects low level signals, but does not affect bright echoes
Reject =
Low level
Low level
136
Contrast agents= also called “ micro _______” of gas in trapped in a shell
-Have different acoustic finger print than blood or tissue. There is a large impedance difference between contrast agents and biologic tissues.
-Create strong reflections, that light up the chambers
Bubbles
137
T/f: output power affects patient exposure
True
138
T/F: when the image is too bright, due to HIGH output power, the lateral and longitudinal resolution degrade
True
139
T/F: gain affects the brightness by changing the amplification of the electronic signals after returning to the receiver.
GAIN does not affect patient exposure.
True
140
ALARA= As ____ as Reasonably Achievable
-MINIMIZE PATIENT EXPOSURE!
Reduce output power FIRST!
-better to use a ____ frequency transducer than increasing output power 🥰
Low
Low
141
Harmonics= multiples of the transducer frequency
Creates ultrasound, imaging by processing reflections, that are _____ the transmitted frequency
Harmonics are created in ______
Non linear behavior created harmonics
TWICE 2x
Tissues!
142
Pulse inversion, harmonic imaging= degrade, temporal resolution while improving _____ resolution (detail)
Spatial resolution
143
Bistable= black or _____
On or ____
high/low contrast?
Narrow/wide dynamic range?
Poor/good contrast resolution?
Bistable=
White
Off
High contrast
Narrow dynamic range
POOR contrast R 😔
144
Gray scale=
______ shades of gray
MULTIPLE LEVELS
low/high contrast?
Wide/narrow dynamic range?
Good/poor contrast resolution?
Gray scale=
Many shades
Low contrast
Wide
GOOD contrast resolution 👍
145
Brightness 🔆 = related to the ______ of the image 💛
BRILLIANCE
146
Contrast= determines the _____ of brilliance is that are displayed.
BISTABLE= high contrast
CONTRAST= RANGE
147
Analog= REAL WORLD 🌎
Continuum of values
-actual weight of an individual
Digital= COMPUTER 🖥️ WORLD= attains to ONLY _____ values
-measuring weight on a digital scale
DISCRETE
148
Scan converters= CHANGES the data _____ from spokes to horizontal lines of the display. Makes gray scale display possible
Format
149
Pixel= smallest/largest element of a digital picture?
PIXEL= smallest !
150
Pixel density=
the MORE pixels per inch, the MORE ____ in the image —-spatial resolution
Low pixel density= _____ detail
High pixel density= ____ detail
Detail
Low pixel density = poor detail
High pixel density= good detail
151
Spatial resolution is related to the number of lines per frame
Few lines= ____ detail
More lines= ____ detail
Few lines= poor
More lines= good
152
Bit = binary digit 🧡
Smallest amount of storage
A bit is ______
Group of bits assigned to each pixel to store gray scale color
More bits=____ shades of gray
= BETTER CONTRAST RESOLUTION 👍
Few bits= ___ gray shades
Poor contrast
Many shades
Less
153
Binary number= group of ____
Series of zeros and ones
Ex: 001001
Digital = binary
Binary numbers based on 2
Bits
154
Byte= group of __ bits!
2 bytes= 16 bits is a word
8
155
What number of shades can be represented by 10 bits?
10 bits=
Multiply by 2 , 10 times
2x2x2x2x2x2x2x2x2x2= 1024!
156
T/F 3 bits can display only 8 shades of gray
2x2x2= 8
True
157
4 bits can display ___ shades
16
158
How many bits are needed to represent 10 shades of gray?
4 bits
159
How many bits are needed to represent 11 shades of gray
4 bits
160
How many bits are needed to represent 15 Shades of Grey
4 bits
161
Preprocessing= manipulating data before storage in scan ______
-altered forever
Converter
162
Post processing= after= performed on a _____ image
FROZEN 🥶
163
T/F electrical signals, created by the PZT are analog
True
164
Analog to digital converter:
Analog-digital = analog signal display on tv
iPod is a D-A conversion
True
165
Ultrasound system
Correct
166
Read magnification = blurry image
-DOES NOT RESCAN, only reads ____ image data!
-__processing (after/frozen)
SAME LINE DENSITY
_____ pixels
Spatial resolution _____ improved
Temporal resolution UNCHANGED
Old images
Post processing
Larger pixels
Not improved
167
Write magnification =
RESCANS, acquires NEW data, gets rid of old data
-writes _____ data
-____processing (before)
-MORE PIXELS
-Improved spatial resolution
-temporal resolution changed
New data
Preprocessing
168
Speckle artifact = grainy
______appearance
Does not represent actual tissue anatomy
________ effects of scattered sound -constructive/destructive
Speckle reduces image contrast and detail (spatial resolution)
Granular
Interference effects
169
Clutter = DOPPLER artifact
Reflections from blood cells are weak or strong?
Reflections from anatomic structures, like muscular and vessel walls= weak or strong?
Strong reflections are called _____
Weak
Strong
Clutter
170
Fill-in interpolation=
___-processing
Improves image _____ by filling in MISSING DATA especially for Deeper parts of a sector-shaped image
Images with ____ line density are most improved with fill in interpolation
Pre
Detail
Low line
171
Spatial compounding =
-scan lines are steered in different angles
-_____array transducers only
-frames are _____, improves signal to noise ratio
Artifacts are ______
Detail is IMPROVED
Temporal resolution is REDUCED
Shadows/edge shadows = eliminated
Phased
Averaged
Reduced
172
Frequency compounding= divides the reflection into sub-bands of _______ frequency ranges. Images are created from each of sub bands.
Images are averaged, improving signal to noise ratio
-speckle artifact reduced
-detail improved
Smaller
173
Dynamic aperture=
Form of ________ receive focusing
-varying the number of elements used to receive the reflectors
-minimizes beam width variation
Electronic
174
Edge enhancement= _______ contrast at a boundary to make image appear sharper/blurry?
-distinguish interfaces
-most useful to emphasize different tissues
-light grays become whiter
-dark grays become darker
EDGE ENHANCEMENT = SHARPER IMAGE
175
Coded excitation:
creates LONG PULSES that contain complex patterns of frequencies & cycles, called a _______
Takes place in a _____
Improves: _______ resolution (most important) , penetration, _______ resolution, contrast resolution
Code
Pulsed
Axial resolution
Spatial
176
Elastography= deformation (change in ______) when FORCE APPLIED
-tissue stiffness
-identifies tissues of different _____________ properties, or different stiffness
Elastography is a form of ultrasonic _______
Shear wave Elastography measures speed _________
Shape
-mechanical
-sideways
177
Rendering= realism
3D/4D
Post processing
-think lion king
Correct
178
Dynamic range= RATIO
ELIMINATES _____level noise
Narrow, dynamic range =
FEW CHOICES
BISTABLE
_____ contrast
Wide dynamic range=
MANY CHOICES
GRAY SCALE
____ contrast
Low
High
Low
179
PACS= Picture Archiving and C___________ System
-computer network
-stores and distributes data
Communications
180
DICOM= Digital Imaging and Communications in M_______
Operating standards for imaging networks
Medicine
181
NAS= Network Attached Storage
Data storage devices
-high capacity
____drives
Hard drives
182
Flow= _____ of a fluid from one location to another
Movement
183
Pulsatile=
-ARTERIAL
-Cardiac _________
-_______ rate
-________ pressure
Contraction
High rate
Higher pressure
184
Phasic=
-VENOUS
-RESPIRATIONS
-_____ rate
-_______ pressure
Low
Lower
185
Flow= _______
How much?
______/time
Liters/min
Volume
Volume
186
Velocity= ________
How fast?
Distance/time
SPEED
187
Laminar flow= plug/parabolic flow
188
True or false: dynamic receive focusing improves lateral resolution at all depths on an image
True
189
As the transduc
