Final Flag Questions Flashcards
1
Q
what does affect power Doppler signal?
A
the density/concentration of RBCs determines the amplitude
more RBCs = increased amplitude = brighter the image
2
Q
what does FFT do?
A
a mathematical process to display various velocities of RBCs traveling through vessels as a graph of velocities over time.
3
Q
what is wrong with this image?
A
improper color box steering
4
Q
Doppler Artifacts
Mirror image occurs with spectral and color Doppler and can be caused by _______ or _______
A
too-high Doppler gain
angle too close to 90 degree
5
Q
Doppler Artifacts
what kind of artifact is this?
A
color bruit
a stenosis, AV fistula, or pseudoaneurysm can cause a “thrill” or tissue vibration due to high velocity - this tissue motion is picked up by color Doppler
6
Q
Fix this image
A
3: increase scale
*notice: aliasing
when you see aliasing, increase the scale!
7
Q
what type of artifact is this?
A
reverberation
appears as multiple, equally spaced reflections on an image
caused by sound bouncing back and forth between two strong reflectors and then returning to the TDR
comet-tail & ring-down artifacts are the forms of reverberation artifacts
8
Q
What type of artifact is this?
A
comet tail
called “twinkle artifact” in color
9
Q
what type of artifact is this?
A
ring-down
10
Q
What type of artifact is this?
A
refraction artifact/ghost image
*image above: refraction from rectus muscles cause duplication of aorta
*image below: the aorta on the right is ghost image
11
Q
Grating lobes can be reduced by…..
A
subdicing: slicing an element into small sub-elements, wired so they act together as a single element apodization: elements receive different voltages when excited (higher voltage in the middle, lower voltage at outermost element) tissue harmonics:
12
Q
what type of artifact is this?
A
slice thickness/section-thickness artifact
*note: the image below is the transverse plane of the same image above. notice that echo within the vessel is gone, which means the echoes in the image above is artifact caused by the elevation
13
Q
what type of artifact is this?
A
enhancement
14
Q
what type of artifact is this?
A
focal banding
15
Q
what type of artifact is this?
A
electronic noise
*there’s nothing you can do about it
16
Q
what type of artifact is this?
A
speckle
17
Q
what type of artifact is this?
A
comet tail
18
Q
what type of artifact is this?
A
multiartifact
19
Q
what type of artifact is this?
A
refraction/ghost image artifact
20
Q
what type of artifact is this?
A
reverberation artifact
21
Q
what type of artifact is this?
A
mirror image
22
Q
what type of artifact is this?
A
reverberation
*apparent pedunculated mass in the apex of the ventricle caused by reverberation artifact
*if there’s motion with reverberation artifact, the motion of the artifact will be in the same direction as the motion of the actual structure
23
Q
what type of artifact is this?
A
clutter artifact
*in PSAX view of the PV and PA
24
Q
what type of artifact is this?
A
ring down artifact
*caused by air in the biliary system
25
what type of artifact is this?
ring down artifact caused by air at the boundary of the diaphragm and lung
26
what type of artifact is this?
TEE image of comet tail artifact (asterisks) created by the two discs from a bileaflet St Jude mechanical prosthetic MV
27
what type of artifact is this?
reverberation (**comet tail**) artifact emanating from the catheter
28
what type of artifact is this?
spurious second aortic valve root caused by **grating lobe artifact**
29
what type of artifact is this?
speed error artifact
30
what type of artifact is this?
mirror of a calcification in liver from the diaphragm
31
what type of artifact is this?
mirror artifact (arrow) of the IVC across the diaphragm
32
what type of artifact is this?
large mirror artifact reflected across the trachea
33
what type of artifact is this?
mirror artifact with lines indicating u/s path which creates the mirror of the anterior MV leaflet
34
what type of artifact is this?
gallbladder with acoustic shadowing from a gallstone
35
what type of artifact is this?
mage of the liver and right kidney with acoustic shadowing caused by the ribs
36
what type of artifact is this?
shadowing and enhancement of the femoral artery
37
_Doppler Waveform Classification_
reduced biphaisc
38
_Doppler Waveform Classification_
triphasic
39
Venous pressure and flow are affected by:
* calf muscle pump
* venous valve
* respiration
40
The term applied when only the information from the selected gate will be processed is:
range resolution
41
Noise in the Doppler signal that is generally caused by high amplitude, Doppler shifted echoes is called:
clutter
42
Signal processing of the Doppler signal is accomplished by the:
Fast Fourier Transform
43
The attribute of colors that permits classification into a color is termed:
hue
44
the artifact that interferes with the ability to detect a low-contrast object is known as:
acoustic speckle
\*acoustic speckle often considered to be an artifact because one-to-one correspondence between image brightness and scanned objects does not exist
45
acoustic energy emitted in a direction different than from the main axis of the sound beam is called:
side lobes
46
Harmonics can be used to eliminate:
reverberation
47
when the Doppler gain is too high, which one of the following artifacts can appear on the image?
1. aliasing
2. cross talk
3. comet tail
4. shadowing
cross talk
\***mirror image** or **crosstalk**: spectral Doppler shows waveform above and below the baseline. It occurs when _the Doppler gain is set to high_ or the _Doppler angle is close to 90 degree_
48
What will improve acoustic speckle
Use of frame rate
Use of compound imaging
49
If you want to improve boarder definition, what imaging enhancement should you use
Spatial compound imaging
50
What can you do to improve visualization of distal acoustic shadowing from calcification
tissue harmonic imaging
51
What artifact is the result of reverberation
comet tail
52
When you select harmonic imaging which artifact is less likely to be observed
grating lobe
53
When you select compound imaging, which artifact is less likely to be observed
Refraction
Shadowing
Enhancement
Acoustic speckle
54
Science of identifying and measuring sound beam potential for biological effects
Dosimetry
\*parameter: intensity, pressure, power
55
unit for pressure
Pascal
\*force per unit area
56
unit for intensity
W/cm2 or mW/cm2
\*power per unit area
57
Acoustic Exposure is determined by:
* sound beam intensity
* exposure time
58
Current FDA regulatory limit SPTA =
**720 mW/cm2**
## Footnote
\*SPTA: The Spatial Peak Temporal Average (***SPTA***) is the average intensity over a time and area
\*SPTA: most common measurement for u/s bioeffects
59
What are the mechanical effects?
examples of MI
Radiation forces
streaming
acoustic **cavitation**
60
What is mechanical index (MI)?
* Used to describe output in terms of possible cavitation
* Relates to likelihood of harmful bioeffects from cavitation
61
If MI is \> 1
risk of cavitation must be weighed against benefits of exam
\*Related to **Temporal Peak**; thus, longer exposure time at high intensities will produce mechanical index \> 1 and possible cavitation
\*If MI is \< 1 = low risk
62
Intensities ______ mW/cm2 will induce cavitation.
\> 3300
63
AIUM accepted **SPTA** intensities range from \_\_\_\_mW/cm2 depending on application (grayscale, color Doppler, M-mode, pulsed Doppler)
1-290
64
\_\_\_\_\_\_\_\_ frequencies increase risk of cavitation
Lower
65
To minimize non-thermal bioeffects…
Decrease output power
Decrease dwell time
66
No adverse non-thermal bioeffects have been reported below ______ (MI) in tissues with existing gas bodies & contrast
0.4 MPa (≈ MI \< 0.4)
67
In tissues without existing gas bodies, **no** adverse non-thermal bioeffects have been reported with MI \_\_\_\_\_
MI \< 1.9
68
MI is proportional to _____ and related to \_\_\_\_\_\_
peak rarefactional pressure
Temporal Peak (TP)
69
**FDA max MI =**
1.9
70
Thermal index should be kept at what number?
Less than 1.0 during all examination
71
What is TI?
Thermal Index
## Footnote
•Used to describe **ratio** between output power and the amount of power it takes _to raise tissue temperature by 1o C_.
72
No confirmed bioeffects under _____ SPTA (unfocused beam)
100 mW/cm2
73
Doppler at high power levels has been shown to cause bioeffects
T or F ?
T
74
HID equation
6/f
75
BUR
**Beam uniformity ratio** (How uniform is the beam?)
## Footnote
* Also called SP/SA factor
* BUR = SP/SA
76
_There are Six different intensities are used to describe the sound beam:_
**• SATA**
**• SPTA**
**• SAPA**
**• SPPA**
**• SATP**
**• SPTP**
Which one of them is the most relevant with thermal bioeffect?
SPTA
\*SP: spatial peak
\*TA: temporal average (measures 100% of time)
77
Which of the following intensity measurement is made during the PRP?
1. SPPA
2. SPTP
3. SATP
4. SPTA
4 (?)
78
What is defined as the action of an acoustic field within a fluid to generate bubbles?
cavitation
79
sensitivity equation & its definition
The ability of a test to detect disease
(How many times the test correctly said there was disease divided by the total number of times there was disease.)
80
specificity equation & its definition
The ability of a test to detect the absence of disease
(How many times the test correctly said there was no disease divided by the total number of times there was no disease.)
81
Accuracy equation & its definition
The percentage of times the test is correct.
82
\_\_\_\_\_\_\_\_ probes have smaller dead zones
Higher frequency
83
If I wanted to evaluate the contrast resolution of a transducer or US system, I would buy a:
1. Doppler phantom
2. AIUM 100mm phantom
3. Tissue equivalent phantom
4. Beam profile phantom
**3.**
## Footnote
The tissue equivalent phantom has taken cysts/masses in it and useful for evaluating contrast resolution
84
The middle rod group of the AIUM phantom scanned from the top measures the:
1. axial resolution
2. depth calibration accuracy
3. lateral resolution
4. sensitivity
1
85
vertical and horizontal accuracy of the electronic calipers. calibration accuracy is performed by scanning the vertical and horizontal equidistant rods from the top.
range accuracy
86
The testing device composed of a series of 0.75mm diameter stainless steel rods arranged in groups suspended in fluid is the:
1. AIUM 100 mm test object
2. string phantom
3. tissue phantom
4. Doppler tissue phantom
1
87
Statistical analysis is used to:
1. find out if the result of the phantom testing is accurate
2. find out if the results of the test object is accurate
3. find out if the results of their clinical testing is accurate
4. find out if the results of their academic testing is accurate
2
88
The following information is needed to find the positive predictive value:
1. all of the positive
2. all of the negatives
3. both the positives and negatives
4. only the true positives and true negatives
1
\*Negative/Positive Predictive value: prevalence of disease
PPV (Positive Predictive Value) - measures how often the test is correct when positive for disease (only includes the positive parameters)
**PPV = TP/(TP+FP)**
89
\_\_\_\_\_\_\_ measures the percentage of examinations that correlated or matched with the gold standard
accuracy
\*Accuracy = (TP)+(TN)/(TP)+(FN)+(TN)+(FP)
\*accuracy falls between the sensitivity and specificity values and PPV and NPV
90
Which adjustment would result in a decrease in MI ?
increase TDR frequency
\*higher frequency = higher amplitude = higher pressure = less risk of MI
91
Briefly describe the relationship between frequency and MI
inverse relationship
\*note: MI is the highest during rarefaction (the lowest pressure)
using higher frequency TDR increases TI and patient's exposure due to attenuation
92
What is HITU?
**high intensity therapeutic ultrasound (HITU**) has re-emerged as a minimally-invasive and non-ionizing therapeutic modality for the treatment of a variety of diseased tissues, including uterine fibroid, prostate, breast, and brain
93
What sonography application has the lowest FDA approved SPTA values
Ophthalmic
94
Which has the highest SPTA value
PW
95
Which intensity parameter is not applicable for continuous wave ultrasound
SPPA and SAPA
96
Which intensity descriptor has the lowest numerical value for the characterization of a pulsed wave ultrasonic field
SATA
97
In an ultrasound phantom, the targets typically used for measuring axial resolution are:
A: Multiple round fluid-filled structures
B: Multiple round Hyperechoic simulated lesions
C: Multiple equidistant rods
D: Closely spaced targets of varying distances
E: Long fluid-filled tubes
Closely spaced targets of varying distances
98
What can you test with a doppler flow patttern
Range gate accuracy
Spectral doppler velocity accuracy
Color doppler penetration
99
String objects are used to evaluate
Doppler accuracy
100
Which of the following is not a clinical for elastography?
1. atherosclerotic plaque
2. dermatology
3. transplant evaluation
4. focal drug delivery
4
101
*Which of the following is NOT an advantage to using harmonics during imaging?*
1. *decreases the amount of noise artifact*
2. *improves lateral resolution*
3. *improves axial resolution*
4. *decreases the amount of grating lobes*
3
Poor axial resolution but can be improved by pulse inversion
102
*By approximately how many decibels does a contrast agent increase the signal of blood?*
1. *10 dB*
2. *30 dB*
3. *5 dB*
4. *20 dB*
2
103
*If the microbubbles in a contrast enhanced ultrasound burst during an exam, what effect is shown on the image display?*
1. Mid level grayscale representing blood flow
2. Very bright echoes representing blood flow
3. Grayscale tissue will display without blood flow
4. Shadowing from increased reflectivity due to large acoustic impedance mismatch
4
104
*Which statement is true of grayscale elastography?*
1. cancers are usually soft and appear as white structures
2. cancers are usually stiff and appear as dark structures
3. cancers cannot be characterized using grayscale
4. cancers usually have the same stiffness as surrounding tissue
2
105
*Which statement is true of the Schlieren Device used to test ultrasound equipment?*
1. It produces image artifacts
2. visualize ultrasound beam as it interacts in a medium
3. It detects rates of absorption
4. It charts detected output power
2
106
***Which is not currently an approved clinical application for focused ultrasound?***
1. *liver carcinoma*
2. fibroid tumors
3. prostate cancer
4. breast cancer
4
107
*A quality assurance device that is used to check for clusters of sound waves located outside the main ultrasound beam axis is a good description of which type of equipment?*
Schlieren Device
108
_Dynamic Elastography_
* Vibration is applied by external vibrator
* Several vibration waves are tracked as they travel in tissue
109
Transient Elastography
Singe vibration is sent and tracked as it travels.
