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Doppler physics 2 > Physics tests > Flashcards

Physics tests Flashcards

1
Q

supine means that you are

A

Laying flat on your back

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2
Q

True or False

Stenosis will have increased velocity within the stenosis

A

True

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3
Q

Tissue vibration associated with turbulence is called a

A

Thrill

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4
Q

Pressure energy is a form of _____________ energy

A

Potential

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5
Q

Turbulent flow profiles may be seen __________ from a significant stenosis in a vessel

A

Downstream

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6
Q

True or False

Plug flow is the velocity in the center of the lumen and gradually decreases to its minimum at the vessel wall

A

False

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7
Q

The three basic forms of blood flow are

A

Pulsatile, phasic and steady

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8
Q

If a patient is supine, what is the arterial pressure at the knee?

A

140 mmHg

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9
Q

During inspiration, the diaphragm moves

A

Down

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10
Q

What happens to venous flow in the legs during inspiration?

A

Decreases

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11
Q

The law of conservation of energy states that the pressure is lowest at

A

the stenosis

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12
Q

True or False

Viscosity describes the energy flow when heat is converted as one object rubs against another

A

False

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13
Q

as blood flows through the circulation, energy is lost in what 3 ways

A

viscous, frictional, inertial

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14
Q

True or False

The Reynolds number for turbulent flow is greater than 2,000

A

True

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15
Q

What is the hydrostatic pressure at the waist if the person is standing?

A

50 mmHg

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16
Q

What is the arterial pressure measured at this patients knee – the hydrostatic pressure is 140mmHg?

A

215mmHg

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17
Q

Blood moving from regions of higher energy to lower energy is called

A

Energy gradient

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18
Q

True or False

Phasic and steady flow are present in venous circulation

A

True

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19
Q

The Reynolds number for laminar flow is less than

A

1500

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20
Q

Flow increases when either

A

pressure gradient increases and resistance decreases

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21
Q

What are the hydrostatic pressures while standing upright in a patient with a blood pressure of 140mmHg

A 
ankle 100
knee 75
waist 50
Mid chest 0
top of head -30
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22
Q

When color gain is set to an inappropriately high level, color appears throughout the color box. A term that describes this is called?

A

Color confetti

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23
Q

Multiple ultrasound pulses that are used to accurately determine blood velocities are called

A

Ensemble

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24
Q

True or False

a wall filter is used to eliminate high frequency Doppler shifts from moving anatomy rather than from moving blood cells

A

False

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25
Q

Which technique is used to perform spectral analysis on color Doppler data?

A

Autocorrelation

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26
Q

True or False

velocity mode distinguishes laminar flow from turbulent flow

A

False

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27
Q

What re the 2 things that are correct about pulsed Doppler transducers?

A

at least 1 crystal and lower sensitivity

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28
Q

The _______ frequency is the highest Doppler frequency than can be measured without the appearance of aliasing

A

Nyquist limit

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29
Q

What is the most common error with Doppler ultrasound?

A

Aliasing

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30
Q

Simultaneous anatomic imaging and Doppler is called

A

Duplex imaging

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31
Q

True or False

Doppler shift is inversely related to the frequency of the transmitted sound

A

False

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32
Q

When the bloos cells are moving _____ to the sound beam, the entire velocity is measured

A

Parallel

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33
Q

assume that a Doppler study is performed and the Doppler shift is 6KHz when the blood’s velocity is 2m/s. If the blood velocity slows to 1m/s. What will the Doppler shift be?

A

3KHz

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34
Q

_____________ is defined by a magnitude and a direction

A

Velocity

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35
Q

This process extracts the low Doppler frequency from the transducer’s carrier frequency

A

Demodulation

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36
Q

True or false

The lumen of a horizontal vessel evaluated with a color Doppler, Sector shaped image contains a single color

A

False

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37
Q

Transducer frequencies of _________ Doppler shifts range are used since they are audible

A

20Hz-20000Hz

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38
Q

Cosine 0 degrees is 1 indicating flow __________ the transducer, whereas cosine 180 degrees is -1, indicating flow _______ from the transducer

A

Toward, away

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39
Q

all of the following occur during expiration except?

a. venous flow in the legs increases
b. the diaphragm rises into the thoracic cavity
c. venous return to the heart decreases
d. abdominal pressure increases

A

d. abdominal pressure increases

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40
Q

True or False
Velocity mode color Doppler and variance mode color Doppler will produce identical images when blood flow patterns are turbulent

A

False

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41
Q

True or False
Velocity mode color Doppler and variance mode color Doppler will produce identical images when blood flow patterns are laminar

A

True

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42
Q

True or False

Absence of color on a color Doppler image always indicates a region of no blood flow

A

False

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43
Q

During a pulsed Doppler exam, aliasing is observed. All of the following may eliminate aliasing except

a. selection of another imaging view with a shallower sample volume
b. selection of another transducer with a lower frequency
c. selection of another imaging view that provides a greater pulse repetition period
d. use of a continuous wave system

A

C. selection of another imaging view that provides a greater pulse repetition period

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44
Q

The highest Doppler frequency without the appearance of aliasing is called the ________ and is equal to ______

A

Nyquist limit, half the emitted PRF

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45
Q

True or False

The higher the pulse repetition frequency of a Doppler exam, the more likely aliasing is to occur

A

False

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46
Q

What happens to venous flow in the legs during inspiration?

A

Decreases

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47
Q

__________ in a fluid system is called voltage, similarly, _________ in a fluid system is called current

A

Pressure, flow

48
Q

What is the arterial pressure measured at the patients knee who is standing and the hydrostatic blood pressure is 14mmHg?

A

215 mmHg

49
Q

During expiration, the diaphragm moves

A

up

50
Q

Gravitational energy is a form of ______ energy

A

stored

51
Q

_______ energy loss in blood is determined by the hematocrit

A

Viscous

52
Q

True or False

Parabolic flow is the velocity in the center of the lumen and gradually decreases to its minimum at the vessel wall

A

True

53
Q

An advantage to power mode Doppler is

A

it is unaffected by Doppler angles

54
Q

True or False

Ghosting artifact show up only on spectral Doppler

A

False

55
Q

True or False

Color Doppler will have crosstalk as an artifact

A

False

56
Q

True or False

Wall filters are used to eliminate low frequency Doppler shifts from moving anatomy

A

True

57
Q

What is the current method of processing Doppler signals that can distinguish laminar and turbulent flow?

A

FFT

58
Q

Which of the following terms is synonymous with spectral broadening?

a. parabolic flow
b. laminar flow
c. turbulent flow
d. plug flow

A

C. turbulent flow

59
Q

when a vessel is colorless, what is the first thing to do?

A

Change the angle

60
Q

Shadows appear then attenuation is too

A

High

61
Q

Enhancement artifact appears as a

A

hyperechoic region

62
Q

Structures with equal echo brightness are described as

A

isoechoic

63
Q

Focal enhancement is a special form of enhancement in which a _________ region of an image appears brighter that tissues at other depths

A

Side to side

64
Q

What are the characteristics of a medium the produces comet tail artifact?

A

strong reflectors, closely spaced, high propagation speed

65
Q

When enhancement occurs, where does it appear on the image?

A

Deeper that a weak attenuator

66
Q

What is the noise resulting from the constructive and destructive interference of small sound wavelets

A

Acoustic speckle

67
Q

True or False

Spatial resolution is related to the overall detain in the image

A

True

68
Q

Portions of an image that are not as bright as surrounding tissues are

A

Hypoechoic

69
Q

Characteristics of reverberation are

A

appear in multiples

70
Q

Which artifact is created when closely spaced reverberations merge

A

comet tail

71
Q

on a mirror image artifact, does the artifact appear Deeper or shallower than the true reflector?

A

Deeper

72
Q

Focal banding has the same appearance as an?

A

incorrect TGC setting

73
Q

True or False

High pixel density declines spatial resolution

A

False

74
Q

If an Ultrasoun pulse travels through a large mass in the body at a speed of 1.2 mm/us, what happens to the position of all echoes produced from reflectors shallower than the mass?

A

They are likely to be placed at the correct depth

75
Q

What type of artifact causes a reflection to be placed at an incorrect depth?

A

Range ambiguity

76
Q

Grating lobes are most commor with which type of transducer technology?

A

Linear arrays

77
Q

Two small cysts, positioned perpendicular to the main axis of a sound beam, are 2.4 mm apart. What determines whether they appear as two distinct images of the system’s display?

A

Beam width

78
Q

True or False
Artifacts are likely to appear when the dimensions of the sound beam area are larger then the dimensions of the reflectors in the body

A

True

79
Q

True or False
all artifacts are errors in imaging that do not represent the true anatomy of the image organ, therefore, they are all undesirable and should be eliminated if possible

A

False

80
Q

What are the 6 assumptions incorporated into the design of every ultrasound system

A
  1. sound travels in a straight line
  2. sound travels directly to a reflector and back
  3. sound travels in soft tissue at exactly 1,540 m/s
  4. reflections arise only from structures positioned in the beam’s main axis
  5. the imaging plane is very thin
  6. the strength of a reflection is related to the characteristics of the tissue creating the reflection
81
Q

Who is responsible for implementing a quality assurance action plan?

A

Sonographer

82
Q

True or False

Flow phantoms are the devices of choice for evaluating soft tissue

A

False

83
Q

Two forms of sensitivity are

A

normal and maximum

84
Q

An acoustic standoff may be used to image

A

superficial structures

85
Q

axial resolution is evaluated by scanning

A

sets of successively closer spaced pins

86
Q

Quality assurance is the routine evaluation of an ultrasound system to guarantee optimal image quality. This should be performed

A

periodically

87
Q

There are 4 requirements for quality assurance program, One of the requirements are:

a. minimize downtime
b. Doppler phantom
c. reduce number of repeat scans
d. repairs

A

d. repairs

88
Q

a proper method for the quality assurance program is

A

image in an identical environment

89
Q

The tissue equivalent phantom will contain which structures?

A

nylon strings, structures that mimic hollow cysts

90
Q

True or False

normal sensitivity should vary from one routine evaluation to the next

A

False

91
Q

Which frequency transducers have a thinner dead zone?

A

Higher

92
Q

The accuracy of reflector depth positioning in A-mode, M-mode, B-mode, and 2-D imaging is called

A

Depth calibration

93
Q

The patient has the capacity to act intentionally, with understanding, and with free will is

A

Informed consent

94
Q

informed consent generally includes the

A

risks, benefits, and uncertainties related to each alternative

95
Q

When can a patient withdraw consent for the procedure?

A

at any time

96
Q

What should the sonographer do when first meeting the patient?

A

introduce yourself

97
Q

True or False
As a sonographer, you have the right to tell the patient what you think their exam findings are before the Dr. comes into the room

A

False

98
Q

True or False
it is best to continue scanning the same type of studies all day and to also add as many patients into the schedule for the best ergonomics on the sonographer

A

False

99
Q

True or False
Gloves should only be worn when you know that you will be handling blood from someone who has something like HIV. You will only need to wash your hands after you scan 5 patients or if you get them dirty

A

False

100
Q

True or False

Workers should nor engage in tasks or activities that will potentially put them at risk of exposure of being harmed

A

True

101
Q

Give 4 ways that a tissue equivalent phantom is similar to soft tissue

A

attenuation
same speed 1540 m/s
scattering characteristics
echogenicity

102
Q

True or False

In vivo is performed within the living body

A

True

103
Q

What is the primary mandate regarding clinical ultrasound?

A

benefits to the patient must outweigh the risks

104
Q

What does a calorimeter do?

A

Measures the total power in a sound beam through the process of absorption

105
Q

What is the science of identifying and measuring the characteristics of an ultrasound beam that are relevant to its potential for producing biological effects?

A

dosimetry

106
Q

Which approach searches for relationship between exposure and response, empirical or mechanistic

A

Empirical

107
Q

What degree in testicular temperature can cause infertility?

A

2-4 degrees

108
Q

True or False

Bone absorbs less acoustic energy than soft tissue

A

False

109
Q

Core temperature is regulated at what degree?

A

37 degree

110
Q

Bubble bursting is also known as

A

Transient cavitation

111
Q

2 forms of cavitation are

A

stable and transient

112
Q

What is a limitation of epidemiologic studies

A

Justification for the exam

113
Q

True or False

it is always fun to scan your friends for entertainment purposes when they are pregnant

A

False

114
Q

True or False

it is safe to scan with a cracked transducer housing

A

False

115
Q

Which intensity is related most closely to tissue heating?

A

SPTA

116
Q

True or False

the transducer exposes a patient to the greatest risk

A

True

Doppler physics 2 (5 decks)

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