Quiz 9 Flashcards
CH 5, 22, 23, 24 (155 cards)
1
Q
Acoustic intensity = _____ power divided by _____ area
A
acoustic power/beam area
2
Q
What are the 5 ways to report intensity?
A
Spatial
Peak
Average
Temporal
Pulsed
3
Q
Why do we care about intensity?
A
intensity effects bioeffects
4
Q
What is the peak intensity?
A
the maximum value.
5
Q
What is the average intensity?
A
the middle value.
6
Q
What is spatial intensity?
A
distance or space
7
Q
What is temporal intensity?
A
refers to TIME
(transmit and receive)
8
Q
What is a pulsed intensity?
A
only refers to transmit
9
Q
What is SPTP?
A
Spatial peak temporal peak
10
Q
What is SPTA?
A
Spatial peak temporal average
11
Q
What is SPPA?
A
Spatial peak pulse average
12
Q
What is SATA?
A
Spatial average temporal average
13
Q
Rank the intensities from largest to smallest.
A
SPTP, IM, SPPA, SPTA, SATA
14
Q
What is the beam uniformity coefficient?
A
spread of a beam in space.
15
Q
What is another name for beam uniformity coefficient?
A
SP/SA FACTOR
16
Q
What is the highest value intensity?
A
SPTP
17
Q
What is the lowest value intensity?
A
SATA
18
Q
What is the duty factor of SP/SA factor?
A
1 or greater
19
Q
In CW ultrasound, the beam is always ______. (on or off?)
A
ON
20
Q
in CW, SPTA is equal to?
A
SPPA
21
Q
In CW, SATA is equal to?
A
SAPA
22
Q
When PW and CW have the same SPTP, CW will have the higher ______?
A
SPTA
23
Q
When PW and CW have the same SATP, CW will have the higher ______?
A
SATA
24
Q
What are the temporal intensities from largest to smallest?
A
Itp, Im, Ipa, Ita
25
What does Isp stand for?
spatial peak intensity
26
What does Isa stand for?
spatial average intensity
27
What does Itp stand for?
temporal peak intensity
28
What does Im stand for?
I max
29
What does Ipa stand for?
pulse average intensity
30
What does Ita stand for?
temporal average intensity
31
Temporal peak intensity (Itp) determines what?
the max intensity in TIME
32
Im (I max) intensity determines what?
the average intensity over the most intense half cycle
33
Ipa (pulsed average intensity) determines what?
the average intensity during pulse duration (on time)
34
What does Temporal average intensity (Ita) determine?
the average intensity during the PRP (on and off time)
35
What is Spatial peak intensity (Isp) ?
the max in space
36
What is Spatial average intensity (Isa) ?
the average over the cross-sectional area of the beam.
37
What is Quality assurance?
evaluation of an US system that is performed ROUTINELY and PERIODICALLY
38
What are the 4 requirements in quality assurance?
Assess system parts
Repairs
Preventative maintenance
Records
39
What are the 5 goals of a QA program?
guarantee proper operation
detect changes
minimize downtime
reduce number of non-diagnostic exams
reduce number of repeat exams
40
What are 3 Devices used for QA?
Tissue equivalent phantom
Doppler phantom
Slice thickness phantom (beam profile)
41
What are 7 performance measurements?
Axial resolution
Lateral resolution
Depth calibration
Horizontal distance calibration
System sensitivity
Registration accuracy
Dead zone
42
What is normal sensitivity?
What is maximum sensitivity?
Accurately displays all structures at a normal sensitivity setting.
Maximum sensitivity is evaluated using max settings in the output power, amplification and TGC
43
What is dead zone?
Region closest to the transducer where images are inaccurate
44
High frequency transducers have a ______dead zone (thick or thin).
thin
45
Low frequency transducers have a _____ dead zone (thick or thin).
thick
46
What are the 2 types of sensitivities?
normal and maximum
47
The dead zone extends from the ______ to the _____depth.
transducer to shallowest depth
48
What type of performance measure uses an acoustic standoff or gel pad in between the pt and transducer for imaging superficial structures?
dead zone
49
What is registration accuracy?
the ability of the system to place reflections in proper positions while imaging from different positions.
50
What is range accuracy?
the ability of the system to place reflectors at the correct depths.
51
What is lateral resolution (PM)?
2 pins that are side by side to the sound beam and are displayed as 2 separate echoes.
52
What is axial resolution (PM)?
2 pins are parallel to the sound beam and are displayed at 2 separate echoes.
53
What are the devices that are used to evaluate equipment performance? (Phantoms)
Tissue equivalent phantom
Slice thickness phantom
Doppler phantoms and flow systems
Fetal ultrasound phantom
54
What is a tissue phatom?
Evaluates gray scale and tissue texture
Evaluates multi focus and adjustable focus phased arrays
Have same speed of sound
as soft tissue
Used to look at gray scale
55
What is a doppler phantom?
evaluates the doppler system by using a moving structure to mimic blood flow.
56
What can doppler phantoms be used for?
depth resolution
volume flow
velocity accuracy
doppler angle
57
What is slice thickness phantom?
evaluates the elevational plane (elevational resolution).
measures the beam perpendicular to the imaging plane.
58
_______slices diminish spatial resolution which reduce the ability to see small reflectors.
thicker
59
What preventative maintenance exams are done by the sonographer?
cleaning the transducers/machines
checking that electrical cords are intact
cleaning of vent
60
What is the gold standard?
What exams are considered the gold standard?
most accurate test
MRI/CT
61
Is ultrasound considered gold standard?
NO
62
What does a chi square compare?
the results of ultrasound to the gold standard tests
63
What is a true positive (TP)?
both test results were positive
64
What is a true negative (TN)?
both test results were negative
65
What is a false positive (FP)?
US test result was positive, and gold standard was negative
66
What is a false negative (FN)?
US test result was negative, and gold standard was positive
67
What does specificity mean in QA?
a test's ability in determine a normal exam
68
What is sensitivity in QA?
a test's ability to find positive exams when there is a problem.
69
What is Positive predictive value (PPV) in QA?
measures the probability that a positive non-invasive exam is correct when a disease is present.
70
What is Negative predictive value (NPV) in QA?
measures the probability that a negative non-invasive exam is correct when NO disease is present.
71
What is accuracy inQA?
determines how good a tests quality is and how effective it is in finding positive and negative results.
72
What is prevalence in QA?
% of a population affected by a disease
73
Sensitivity is determined by _____ and _____ on the chi square?
true positive and false negative
74
Specificity is determined by _____ and ____ on the chi square?
true negative and false positive
75
A positive predictive value is determined by _____ and _____ on a chi square.
true positive and false positive
76
A negative predictive value is determined by _____ and _____ on a chi square?
true negative and false negative
77
What is a hydrophone?
small transducer that measures the characteristics of a sound beam.
78
What type of pressure can hydrophones measure?
acoustic
79
What 4 things can a hydrophone measure on an US machine?
PERIOD
PRP
PRF
PD
80
What are the 2 types of hydrophones?
probes and membrane hydrophones
81
What is radiation force balance?
the force that is exerted when a wave hits a target that absorbs, scatters or reflects energy.
82
Measured radiation force relates to the _____ or ____ of the sound beam.
intensity or power
83
What is Acousto-optics?
interaction of sound and light
84
What is the name of the shadowing system that Acousto-optics uses?
Schlieren imaging
85
What does Schlieren imaging do?
to view the shape of an US beam in a medium.
86
What are the 3 devices that measure the conversion of sound energy to heat?
1. Calorimeter
2. Thermocouple
3. Liquid crystal
87
What is a calorimeter?
Measures TOTAL power in a sound beam through absorption
88
What is a thermocouple?
Measures the sound beams power at a PARTICULAR location
89
What is a liquid crystal?
Measures the change in temperature. (changes color to indicate different temps.)
90
What is acoustic exposure?
the amount of acoustic energy a pt is exposed to.
91
Acoustic exposure utilizes ________ principle.
ALARA
92
Use a _____ receiver gain and a _____ output power.
High RG
Low output
93
What are the 2 bioeffect mechanisms?
Thermal and Mechanical
94
What is thermal index (TI)?
predicts an increase in temperature which increases the chance of bioeffects.
95
Maximal heating is related to the beam's _____ intensity.
SPTA
96
SPTA should NOT exceed what?
1 W/cm2 (focused beam)
97
What is Mechanical Index (MI)?
cavitation
98
There is no confirmed bioeffects for temperatures up to _____ and less than_____ hours.
2 degrees Celsius
less than 50 hours
99
An exam can cause temperature elevation and harm a fetus is it exceeds ______.
41 degrees Celsius
100
What are the 3 thermal indices used for imaging applications?
TIS
TIB
TIC
101
What is TIS?
What is TIB?
What is TIC?
Soft tissue
Bone
Cranial bone
102
What type of modalities has a higher risk of thermal bioeffects?
non-scanned
103
Why do non-scanned modalities have a greater risk of thermal bioeffects than scanned modalities?
because the beam is transmitted in the same direction causing heat to build up.
104
What are the 2 non-scanned modalities?
B-mode and color doppler
105
Why are scanned modalities safer from bio effects?
because they scan information over a wide plane which gives time for the heat to dissipate.
106
What are the 4 scanned modalities?
CW doppler
PW doppler
M-mode
A-mode
107
What is mechanical bioeffects (non-thermal)?
damage that is caused by the oscillation of the sound wave on tissue.
108
What are the3 types of mechanical bioeffects?
Radiation force
Cavitation
Streaming
109
What does Radiation force,
Cavitation, and Streaming cause the formation of?
gas bubbles
110
Why is cavitation harmful?
the bubbles can get larger and rupture.
111
What is the 2 types of cavitation?
Stable
Transient (Inertial)
112
What is stable cavitation?
Bubbles that oscillate in a stable manner and do NOT rupture.
113
What is transient cavitation?
-causes the most bioeffects
-large bubbles rupture causing an increase in tissue temp.
-cell death in affect area
114
What is radiation force?
the force that is exerted by the sound beam on a tissue
115
Radiation force is a type of ______ index.
Mechanical index
116
When streaming of fluids distorts or disturbs biological structures is caused by what force?
Radiation force
117
What is microstreaming?
stress from fluids that surround the cells
118
Microstreaming is used in what type of ultrasound?
Therapeutic
119
What is Dosimetry?
identifying and measuring the characteristics of an US beam that are relevant to its potential bioeffects.
120
What is In-vivo?
performed within the body
121
What is In-vitro?
performed outside the body.
122
T/F Bioeffect research can be conducted using in-vivo or in-vitro.
True
123
What does in-vitro research tell us about ultrasound?
High intensities can cause genetic damage and cell death
124
What is epidemology?
population studies
125
What is empirical?
exposure response using clinical surveys
126
The best epidemiologic studies are _____ and _____.
Prospective and randomized
127
What are limitations of epidemiologic studies?
data can be inaccurate because of age, MI, TI, and the number of scans can be inconsistent between pts
128
What are prospective studies?
Provides accurate information from medical records.
129
What is retrospective?
Less desirable data that is collected from the past.
Inaccurate or incomplete
130
Randomized studies create 2 groups of pts. What do they consist of?
One group has been exposed to ultrasound, and one is unexposed
131
What does AIUM state?
Ultrasound is safe when properly used but can cause bioeffects with therapeutic US
Bioeffects depend on several factors (exposure conditions, cavitation, tissue type)
Monitoring techniques should be used
132
A lower MI = ____(more or less) cavitation, ____(more or less) pressure and ____(high or low) frequency.
less
less
higher
132
A high MI = ____(more or less) cavitation, ____(more or less) pressure, and ____(high or low) frequency.
more
more
lower
133
What are the 4 advancements in imaging?
Virtual beamforming
Big data
Enhanced digital signal processing (eDSP)
Bit by bit frame creation
134
With conventional beaming, _______ is traded for _______ for better images.
Frame rate is traded for spatial resolution
135
How does a conventional beamformer work?
Pulses fire separately and return separately
136
What does a virtual beamformer use?
Graphics processing unit (GPU)
137
What does a Graphics processing unit (GPU) do?
processes many pieces of data at the same time
useful for machine learning and video editing
138
What does virtual beamforming eliminate that a conventional beamformer cant?
Beam divergence/breakage
Slice thickness
Lobe artifacts
139
What does virtual beamforming improve?
improves contrast and temporal resolution
increases sensitivity and penetration
reduces artifacts
improves doppler operation (grayscale, color, spectral)
140
What is big data?
ability to acquire, transfer, process and store large amounts of digital data received through virtual beamforming.
141
How is big data utilized in ultrasound?
Provides new diagnostic possibilities using the interaction of acoustic energy and soft tissue.
142
What is enhanced digital signal processing (eDSP)?
Analyzes the acoustic data from the virtual beamforming
uses software to identify, separate information into digital "siloes".
Provides a thin ultrasound beam image
further processes big data
143
What are the benefits of eDSP?
improves temporal resolution
enhances B-mode
tissue transparency
attenuation imaging
automated sound speed compensation
automated B-mode measurements
144
What is bit-by-bit frame creation?
utilizes a line-by-line frame method.
data that is populated by the big data is processed into individual pixels using bit-by-bit frame creation.
after creation, additional digital software can be applied.
145
Big-by-bit frame creation allows for what?
Speckle tracking
Enhanced contrast
Vector flow imaging
Hemodynamic imaging
Temporal resolution exceeds 1000 frames/sec
146
What is synthetic spatial compounding?
Conventional imaging takes data from 3 different angles to produce a single frame
Uses data received from eDSP that reduces frame time
147
What does it mean to have respect for patient autonomy?
patient has free will to decide what is best for them
Informed Consent
148
What is Nonmaleficence?
avoid harm to the pt
149
What is Beneficence?
actions that should benefit the pt
150
What is justice?
all are treated equally
151
What is informed consent?
The patient makes an informed, educated, and voluntary decision whether they wish to proceed
152
What are the 4 major principles of medical ethics?
Respect for patient autonomy
Nonmaleficence
Beneficence
Justice
153
Lab policies must include:
Ergonomics
Sonographer health
Limit the number of studies
Educational programs
154
Standard Precautions include:
All patients should be treated as potentially infectious.
Routine hand washing
Protect yourself from contact of body fluids
