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PHYSICS > Chapter 6 Kremkau > Flashcards

Chapter 6 Kremkau Flashcards

1
Q

the part of the instrument that accomplishes electronic beam scanning, apodization, steering, focusing, and aperture with arrays

A

beam former

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2
Q

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

A

image former

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3
Q

an electronic device that rapidly performs calculations to accelerate the creation of images

A

Graphics processing unit (GPU)

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4
Q

the beam

A

physical beam

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5
Q

ultrasound waves are produced in pulses, not continuously, because the same crystals are used to generate and receive sound waves, and they cannot do both at the same time

A

pulse-echo principle

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6
Q

a line produced on a display that represents ultrasonic echoes returning from the body

A

scan line

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7
Q

an imaginary reception beam that can be thought of as determining the echo produced at each pixel location in the image

A

virtual reception beam

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8
Q

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

A

virtual transmission beam

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9
Q

The underlying principle upon which conventional (Principle 1) sonography operates is:

A

the pulse-echo principle

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10
Q

The underlying principle upon which more recent, sophisticated (Principle 2) sonography operates is:

A

the virtual beam principle

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11
Q

Which is not needed with Principle 2 sonography?
a. transmitted beam
b. multiple-transmit focus
c. reception focus
d. TGC

A

multiple-transmit focus

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12
Q

Which is not a reason for improvement of detail resolution with Principle 2 sonography?
a. shorter transmit pulses
b. reception focus at each pixel location
c. massive postprocessing with GPUs
d. retrospective beam forming

A

shorter transmit pulses

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13
Q

Which is not a reason for improvement of temporal resolution with Principle 2 sonography?
a. shorter transmit pulses
b. fewer transmit pulses
c. no multiple focusing
d. speed of GPUs

A

a

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14
Q

Which is not significantly improved with Principle 2 sonography?
a. axial resolution
b. lateral resolution
c. temporal resolution
d. contrast resolution

A

a

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15
Q

Physical beam forming applies to ____ sonography

A

both principle 1 and principle 2

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16
Q

Virtual beam forming applies to:

A

principle 2

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17
Q

Multiple transmission focus control applies to:

A

principle 1

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18
Q

Retrospective beam forming applies to:

A

principle 2

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19
Q

Improving detail resolution sacrifices temporal resolution is true for:

A

principle 1

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20
Q

Simultaneous gray-scale, Color-doppler, and spectral-Doppler applies to:

A

principle 2

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21
Q

Principle 1 employs mostly:

A

focused ultrasound beams

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22
Q

Principle 1 yields higher frame rates than Principle 2.

A

false

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23
Q

Shear wave elastography operates on Principle 1

A

false

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24
Q

Principle 2 enables the entire image to be in focus

A

true

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25
Q

Principle 2 yields improved penetration

A

true

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26
Q

Principle 2 does not impact Doppler operations

A

false

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27
Q

Principle 2 produces laser-thin ultrasound beams

A

false

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28
Q

Multiple transmit focuses degrade temporal resolution with _____.

A

principle 1

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29
Q

Reception focus principle applies to:

A

both principle 1 nor principle 2

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30
Q

A doppler shift at 60 degrees is ____ what it would be at 0 degrees

A

one half

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31
Q

A change in doppler frequency caused by motion of a source or a reflector defines

A

Doppler effect

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32
Q

A nonsteady flow with acceleration and deceleration over the cardiac cycle is called _____

A

pulsatile flow

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33
Q

Continuous wave doppler shifts are detected within the _______

A

Overlapped region of the transmitting and receiving beams

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34
Q

Determining the direction of the doppler shift voltages is accomplished by the _______

A

Phase quadrature detector

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35
Q

Doppler measurements are not reliable at doppler angles greater than

A

60

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36
Q

Doppler shift does not depend on the

A

flow direction

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37
Q

Echoes arrive from the sample volume depth at a rate equal to

A

the pulse repetition frequency

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38
Q

for a given flow, the greater the doppler angle, the _____ the doppler shift

A

less

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39
Q

Gases, nutrients, and waste products are exchanged through the walls of

A

capillaries

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40
Q

if pressure differences in a straight vessel increase, the flow rate

A

increases

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41
Q

Motion toward the transducer demonstates

A

a positive Doppler shift

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42
Q

Poise is a unit given for ____

A

viscosity

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43
Q

Poiseuille’s equation states that, if the flow rate increases the

A

tube diameter has increased

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44
Q

Resistance to flow offered by a fluid in motion describes

A

viscosity

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45
Q

Sound reflects totally at the wall-blood boundary once the doppler angle is less than ____ degrees

A

30

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46
Q

Spectral broadening may be produced by

A

beam spreading in arrays

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47
Q

The doppler equation relates the doppler shift to the

A

flow speed and frequency

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48
Q

the amount of blood passing a point per unit of time defines

A

volumetric flow rate

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49
Q

The angle of incidence is not important with which doppler display>

A

power

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50
Q

The decreased pressure is regions of high flow speed is called

A

Bernoulli effect

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51
Q

The difference between the emitted frequency and the echo frequency returning from a moving scatter is called the

A

Doppler shift

52
Q

The fast fourier transform derives the Doppler

A

spectrum

53
Q

The horizontal presentation in the spectral display represents

A

time

54
Q

The resistance of the _____ accounts for about one half of the total resistance in the systemic circulation.

A

arterioles

55
Q

The volumetric flow rate is equal to _____

A

average flow rate across the vessel multiplied by the cross sectional area of the vessel

56
Q

The width of the sample volume is determined by the

A

beam width and sample volume depth

57
Q

Turbulent flow is a form of _____ flow

A

nonlaminar

58
Q

Variance color maps demonstate a change of hues from _____

A

left to right

59
Q

Vertical thickening of spectral tracing is called

A

spectral broadening

60
Q

What advantage does spectral analysis have when compared to other doppler techniques

A

spectral analysis displays peak systolic velocities

61
Q

what is required for flow to occur

A

pressure difference

62
Q

what is the driving force behind blood flow

A

pressure

63
Q

what type of blood flow demonstrates layers of fluid sliding over each other?

A

laminar

64
Q

Which flow type demonstrates a flow velocity that is essentially constant across the vessel

A

plug

65
Q

which matter is considered fluid

A

gases and liquids

66
Q

What Doppler display cannot determine flow direction?

A

power

67
Q

What doppler technique must be time shared

A

Duplex imaging

68
Q

What is an advantage of pulsed Doppler

A

depth of sample volume can be accurately selected

69
Q

What pulsed doppler technique is most likely to demonstrate slow flow velocities in deep vessels?

A

power doppler

70
Q

Which system control eliminates low-frequency doppler shifts

A

wall filter

71
Q

Which type of blood flow demonstrates a chaotic flow pattern?

A

turbulent

72
Q

Which type of blood flow would demonstrate the narrowest range of doppler shift frequencies?

A

plug

73
Q

With color doppler imaging, the priority control _____

A

selects which gray-scale echo strength will demonstrate color

74
Q

_____ describes the volumetric flow rate as a constant

A

Continuity rule

75
Q

An imaginary laser thin transmitted ultrasound beam that can be thought of as producing excellent detail resolution throughout the image describes a _____

A

virtual transmission beam

76
Q

The retrospective beam forming process occurs in the

A

image former

77
Q

What contributes to improved temporal resolution in Principle 2?

A

fewer pulses and broad physical beams

78
Q

What type of blood flow demonstrates layers of fluid sliding over each other

A

laminar

79
Q

resistance of the blood flow depends on the radius of the

A

tube to the fourth power

80
Q

if pressure difference in a straight vessel increase, the flow rate

A

increases

81
Q

Tiniest vessels in the human body

A

capillaries

82
Q

the state of the downstream arterioles is reflected in the

A

arterial diastolic flow

83
Q

For a given flow, the greater the doppler angle, the less the

A

doppler shift

84
Q

The maximum normal flow speed in the circulation is

A

100 cm/s

85
Q

Variance color maps demonstrate a change of hues from

A

left to right

86
Q

which system control eliminates low frequency doppler shifts

A

wall filter

87
Q

the width of the sample volume is determined by the

A

beam width and sample volume depth

88
Q

the horizontal presentation in the spectral display represents

A

time

89
Q

spectral broadening may be produced by

A

beam spreading arrays

90
Q

continuous wave doppler shifts are detected within the

A

overlapped region of the transmitting and receiving beams

91
Q

the normal adult circulatory system contains ____ of blood

A

5L

92
Q

In a stenosis, flow speed increases and pressure

A

decreases

93
Q

The doppler shift is proportional to the

A

blood flow speed

94
Q

volumetric flow rate is proportional to

A

flow resistance

95
Q

if the pressure difference between two point increases, the flow rate

A

also increases

96
Q

Blood flows from the left and right ventricles into the _____ and _____ respectively

A

aorta
pulmonary artery

97
Q

According to Poiseuille’s equation, if the radius of the tube increases, the flow rate

A

increases

98
Q

If the flow speed increases, the pressure

A

decreases

99
Q

Higher operating frequencies produce ____ doppler shifts

A

larger

100
Q

If viscosity increases, flow rate

A

decreases

101
Q

Increased flow speed through a stenosis can cause

A

distal turbulence

102
Q

Multiple transmission focuses are used in

A

Principle 1

103
Q

What contributes to improved temporal resolution in principle 2

A

fewer pulses
broad physical beams

104
Q

The retrospective beam forming process occurs in the

A

image former

105
Q

Physical ultrasound beam forming is required in

A

both principle 1 and principle 2

106
Q

Weakly focused or unfocused ultrasound beams are characteristic of

A

principle 2

107
Q

The characteristic of fluid that offers resistance to flow is called

A

viscosisty

108
Q

Flow is a response to pressure ______ or ______

A

difference
gradient

109
Q

If pressure difference is doubled, volumetric flow rate is _______

A

doubled

110
Q

If flow rate is doubled, volumetric flow rate is

A

halved

111
Q

Flow resistance in a vessel depends on

A

vessel length
vessel radius
blood viscosity

112
Q

if operating frequency is doubled, the doppler shift is

A

doubled

113
Q

if flow rate is doubled, the doppler shift is

A

doubled

114
Q

Color doppler instruments use an ______ technique to yield doppler information in real time

A

autocorrelation

115
Q

In practice, approximately _____ pulses are required to obtain one line of color-doppler information

A

10

116
Q

color map baselines are always represented by

A

black

117
Q

doubling the width of a color window produces a ____ frame rate

A

halved

118
Q

Color doppler frame rates are ______ gray scale rates

A

less than

119
Q

Doppler power imaging indicates (with color) the _____ of flow

A

presence

120
Q

Stenosis affects

A

spectral broadening

121
Q

Virtual beam forming applies to

A

Principle 2

122
Q

Multiple transmission focus control applies to

A

Principle 1

123
Q

Retrospective beam forming applies to

A

Principle 2

124
Q

Improving a detail resolution sacrifices temporal resolution is true for

A

principle 1

125
Q

Simultaneous gray scale, color doppler, and spectral doppler applies to

A

Principle 2

126
Q

Principle 1 employs mostly

A

focused ultrasound beams

127
Q

Reception focus principle applies to

A

both principle 1 and principle 2

PHYSICS (26 decks)

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