Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DSM PHY > SPI > Flashcards

SPI Flashcards

1
Q

Bioeffects

A

Effect of US waves on living organisms, including their composition, function, growth, origin, development, and distribution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Acoustic exposure

A

The amount of acoustic energy the patient receives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

ALARA

A

As low as reasonably achievable. Used to reduce bio effects in humans and the fetus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Cavitation

A

Interaction of the sound wave with microscopic has bubbles found in tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Epidemiology

A

Studies of various factors determining the frequency and distribution of diseases in the human community

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Ergonomic

A

Study of the human body at work.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In vitro

A

Outside living organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In vivo

A

In or on living tissue (animal testing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mechanical Index (MI)

A

Describes the likelihood of cavitation occurring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

OSHA

A

An act passed by congress to assure safe and healthful working conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Pulse Average (PA)

A

Average intensity throughout the pulse duration.

For continuous wave, pulse average is equal to temporal peak

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Spatial Average (SA)

A

Average intensity across entire sound beam.

Equal to total power across the beam/ beam area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Spatial Peak (SP)

A

Peak intensity found across the sound beam

Center

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Temporal Average (TA)

A

Average intensity during pulse repetition period.

Equal to (PA)x duty factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Temporal Peak (TP)

A

Greatest intensity during the pulse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Thermal index (TI)

A

Relates to the heating of tissue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

FDA regulates

A

Ultrasound instruments according to the application, output intensities, and thermal and mechanical indexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

AIUM recommends

A

Prudent use of Ultrasound in the clinical environment by minimizing exposure time and output power

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

ALARA principle uses

A

High receiver gain and low output power

Power should be decreased in OB and Pediatric exams

Exposure should be kept to a minimum and benefits must outweigh risks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Intensity

A

Power/area

W/cm^2

Varies across sound beam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Intensity is highest

A

In the center of the sound beam and falls off near the periphery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Intensity starts

A

High and decreases near the end of the pulse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Intensity with pulsed wave Doppler

A

Is greater than with continuous wave Doppler.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

SATA

A

Spatial Average-Temporal Average

Lowest intensity for a given sound beam

Heat is most dependent to this intensity

Measured during both pulse and receiving time (prp)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

SPTA

A

Spatial Peak-Temporal Average

Used to describe pulse Ultrasound intensities and determine bio effects

Measured during PRP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

SAPA

A

Spatial Average- Pulse Average

Measured during pulse duration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

SPPA

A

Spatial Peak- Pulse Average

Measured during pulse duration

Intensity that occurs during pulse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

SATP

A

Spatial Average- Temporal Peak

Used to describe pulse Ultrasound intensities

The average intensity within the beam at the highest intensity in time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

SPTP

A

Spatial Peak - Temporal Peak

Highest intensity value for a given sound beam

Peak intensity of sound beam in both time and space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Instrument Output

A

Imaging instruments have lowest output intensity

PW Doppler has highest output intensity

Determined by a hydrophone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Stable cavitation

A

Involves microbubbles already present in tissue

When pressure is applied microbubbles will expand and collapse

Bubbles can intercept and absorb a large amount of acoustic energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Transient cavitation

A

Dependent of the pressure of the ultrasound pulse

May occur with short pulses

Bubbles expand and collapse violently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Aliasing

A

A misrepresentation of the Doppler shift in a negative direction occurring when the pulse repetition frequency is set too low

Exceeds nyquist limit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Bernoulli effect

A

Pressure reduction in a region of high flow speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Bruit

A

Auscultatory sound within an artery produced by turbulent blood flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Clutter

A

Noise in the Doppler signal caused by high-amplitude Doppler shifts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Doppler effect

A

Observed frequency change of the reflected sound resulting from movement relative to the sound source or observer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Doppler shift

A

Frequency shift created between the transmitted frequency and received frequency by an interface moving with velocity at an angle to the sound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Energy gradient

A

Energy difference between two points.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Flow

A

To move in a stream, continually changing position and direction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Gate

A

Electronic device controlling the transmission or reception of a Doppler signal; size of the gate is determined by the beam diameter, receiver gate length, and length of the ultrasound pulse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Hemodynamics

A

Science or physical principles concerned with the study of blood circulation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Hue color map

A

The perceived color; any one or a combination of primary colors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Hydrostatic pressure

A

The pressure created in a fluid system, such as the circulatory system.

The hydrostatic pressure is zero in supine

When upright the pressure is negative above the heart and positive below the heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Nyquist limit

A

The highest frequency in a sampled signal represented unambiguously; equal to one half the pulse repetition frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Doppler packet

A

Positioning of multiple pulsed Doppler gates over the area of interest.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Peak velocity

A

Maximum velocity at any given time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Plug flow

A

Speed is constant across the vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Pressure gradient

A

Difference in pressure required for flow to occur.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Pulsatility index

A

A parameter used to convey the pulsatility of a time-varying waveform.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Reynolds number

A

Predicts the onset of turbulent flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Resistant index

A

Difference between the maximum and minimum Doppler frequency shifts divided by the maximum Doppler frequency shift.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Sample volume

A

Electronic device that controls the region of Doppler flow detection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Saturation color map

A

Degree to which the original color is diluted with white; the paler the color (or less saturated it is) the faster the flow velocity; the purer the color, the slower the flow velocity.

55
Q

Spectral broadening

A

Increase in the range of Doppler shift frequencies displayed resulting in a loss of the spectral window; usually seen with stenosis.

56
Q

Stroke volume

A

Amount of blood moving in a forward direction; blood being ejected.

57
Q

Variance mode

A

The average velocity is calculated, with the colors placed side by side

58
Q

Velocity

A

Rate of motion with respect to time.

59
Q

Velocity mode

A

All measured velocities for each gate are averaged, then the colors are arranged up and down.

60
Q

Volume flow rate

A

The quantity of blood moving through the vessel per unit of time.

61
Q

Blood flows from

A

Higher pressure to lower pressure

62
Q

Types of blood flow

A

Low-resistive

High-resistive

63
Q

Low resistive flow

A

Slow upstroke in systole and large amount of diastolic flow

ICA

64
Q

High resistive flow

A

Sharp upstroke in systole
Very little diastolic flow

ECA

65
Q

Laminar flow

A

Flow where layers of fluid slide over each other

Max flow velocity located in center of the artery

Min flow velocity located near arterial wall

Found in smaller arteries

66
Q

Parabolic flow

A

Type of laminar flow

Average flow velocity is equal to 1/2 the max flow speed at center

67
Q

Plug flow

A

Constant velocity across the vessel

Found in large arteries (aorta)

68
Q

Pulsatile flow

A

Steady flow with acceleration and deceleration over the cardiac cycle.

Includes added forward flow and or flow reversal throughout cardiac system

69
Q

Turbulent flow

A

Chaotic flow
Characterized by eddies and multiple flow velocities

Onset predicted by a Reynolds number greater than 2000

Caused by a curve in a vessel’s course or decrease in vessel diameter

70
Q

Venous flow

A

Little resistance to flow
Low-pressure, non pulsatile flow

Lowest when patient is laying flat

71
Q

Phasic flow

A

Flow variation during respiration

72
Q

Inspiration

A

Increases abdominal pressure,

Decreases venous flow from lower extremities, decreases thoracic pressure, increases flow from upper extremities

73
Q

Expiration

A

Increases thoracic pressure, decreases venous flow to upper extremities, decreases abdominal pressure, increases venous flow to lower extremities

74
Q

Doppler Shift

A

The change in frequency caused by motion. Difference between the emitted frequency and the echo frequency returning from moving scatters.

75
Q

Doppler shift is proportional to

A

The flow speed and source frequency

76
Q

Doppler shift is dependent on

A

Doppler angle

77
Q

Cosine values are

A

Inversely related to Doppler angle

78
Q

Doppler shift equation

A

Doppler shift= 2 x frequency x velocity x cosine Doppler angle / propagation speed

79
Q

Doppler effect

A

Units- Hz
Result from motion of blood
Observed frequency or wavelength change of the reflected sound is a result of reflector movement relative to the source or observer

80
Q

Doppler effect is used to

A

Determine flow velocity and direction of moving reflectors

81
Q

Doppler shift occurs in

A

Audible range

82
Q

Rayleigh scattering results from?

A

RBC’s being smaller than the wavelength of the sound beam

83
Q

There is no doppler shift if

A

The received and transmitted frequencies are the same

84
Q

Positive Doppler shift

A

Occurs when the received frequency is greater than the transmitted frequency

85
Q

Negative Doppler shift

A

Occurs when the received frequency is is lower than the transmitted frequency

86
Q

Doppler shift is inversely related to

A

The angle and source of reflector

87
Q

What may directly affect the intensity of the Doppler shift?

A

Concentration of red blood cells

88
Q

Doppler shift is directly related to

A

Operating frequency

89
Q

What may be necessary to achieve Doppler shifts at deeper depths?

A

A lower frequency transducer

90
Q

Continuous Wave Doppler

A

2 crystals- on transmitting, one receiving

Displays only waveforms

Large sample volume in region where transmitting and receiving sound beams converge

Sound is transmitted 100% of the time

91
Q

Advantages of Continuous Wave Doppler

A

Ability to measure high velocities (no aliasing)

Use high frequencies

Sensitive to low flow velocities

Small probe size

Simplest form of Doppler

92
Q

Disadvantages of Continuous Wave Doppler

A

Lack of imaging ability

Interrogates all vessels in the sampling area (range ambiguity)

93
Q

Pulse Wave Doppler

A

Single crystal to transmit and receive Doppler info

Displays image of the vessel and Doppler info

Sample volume (gate) is placed within a specific vessel

Minimum of 5 cycles per pulse and up to 30 cycles per pulse

94
Q

Advantages of Pulse Wave Doppler

A

Operator- adjusted placement of the sample volume (range resolution)

Allows smaller sample volume

Duplex imaging capabilities

95
Q

Disadvantages of Pulse Wave Doppler

A

Maximum detectable Doppler shift determined by aliasing

96
Q

Duplex imaging

A

Combination of 2-D gray scale and Doppler information

Electronic scanning permits switching between imaging and doppler functions several times per seconds, giving the impression of simultaneous imaging

Imaging frame rates are decreased to allow for interlaced acquisition of Doppler info.

97
Q

Advantage of Duplex Image

A

Ability to place sample volume in a specific vessel

98
Q

Disadvantage of Duplex Imaging

A

Decrease in gray-scale imaging frame rate

99
Q

Spectral analysis

A

Allows visualization of the Doppler signal

Provides quantitative data used for evaluating the Doppler shift

High and low impedance conditions downstream give rise to different spectral displays

100
Q

Spectral analysis axis

A

Vertical- frequency shift (velocity)

Horizontal- time

101
Q

Spectral analysis uses

A

Fast Fourier Transform to convert Doppler shift information into a visual spectral analysis

102
Q

Fast Fourier Transform

A

Breaks down the complex signals of the Doppler shift into individual frequencies

103
Q

Advantages of Spectral Analysis

A

Allows measurement of peak, mean, and minimum flow velocities, flow direction and characteristics of blood flow

Presents Doppler shift frequencies in frequency order

104
Q

Disadvantage of Spectral Analysis

A

Cannot accurately measure high velocities without aliasing

105
Q

Color Flow Doppler

A

Presents 2-D color coded info of motion imposed over a gray scale image

Displays color coded flow velocity and direction

106
Q

Color maps

A

Velocity and Variance modes

107
Q

Doppler packets

A

*

108
Q

Color info is obtained in?

A

Packets

Positioning of multiple sample gates over the area of interest

109
Q

Increasing the length of the color box does what?

A

Decreases frame rate

110
Q

Changing the Doppler angle in an image does what?

A

Produces various colors in different locations

111
Q

Autocorrelation is necessary for?

A

Rapid obtainment of Doppler shift frequencies

112
Q

Advantages of Color Flow Doppler

A

Detect flow quickly

Aids in distinguishing low flow velocities

Determines blood flow direction

Non vascular motion (urethral jets)

113
Q

Increasing Doppler packet size will do what?

A

Increase sensitivity and accuracy

Decrease temporal resolution and frame rate

114
Q

Disadvantages of Color Flow Doppler

A

Displays mean velocity

Over-gaining of gray scale image decreases color sensitivity

Less accurate that spectral analysis

115
Q

Color Flow Doppler and aliasing

A

Occurs at lower velocities compared to pulse and continuous wave Doppler.

116
Q

Power Doppler

A

Real time image of the amplitude of the signal.

Displays 2-D color image representing blood flow imposed over a gray scale image

117
Q

Advantages of Color Doppler

A

Increases sensitivity to Doppler shifts in slow low flow within deep vessels

Insensitive to Doppler angle effects and aliasing

Better wall definition

118
Q

Disadvantages of Power Doppler

A

Does not demonstrate flow direction, speed, or character information.

119
Q

Doppler artifacts

A

Aliasing

Flash

Mirror imaging

Range ambiguity

120
Q

Causes of Aliasing

A

Doppler shift exceeds one half PRF

Undersampling of the Doppler shift

121
Q

What does aliasing look like?

A

Improper representation of the information sampled

Wrap around of the pulse wave or color Doppler display

Incorrect flow direction

122
Q

How to fix aliasing

A 
Increase PRF (scale)
Increase Doppler angle
Adjust baseline to zero
Decrease operating frequency 
Decrease depth of the sample volume 
Change to continuous wave
123
Q

Flash artifact

A

Sudden burst of Color Doppler extending beyond the region of blood flow.

124
Q

Flash artifact is caused by

A

Tissue or transducer motion

125
Q

How to fix flash artifact

A

Increase PRF
Decrease color gain
Increase filtering of low flow velocities

126
Q

Mirror imaging artifact

A

Duplication of a vessel or Doppler shift in the opposite side of a strong reflector

127
Q

What causes mirror artifact

A

Doppler gain too high

128
Q

How to fix mirror imaging

A

Decrease color gain

Use a different acoustic window

129
Q

Range ambiguity

A

Doppler shift received are not all from the same vessel

130
Q

What causes range ambiguity?

A

Improper placement of the sample volume

131
Q

How to fix range ambiguity

A

Readjust placement of a sample volume

132
Q

Pulsatility index

A

Most sensitive ratio

Used to convey the pulsatility of a time varying waveform

Equal to peak systole - end diastole / mean velocity

ABD and OB imaging

133
Q

Resistive index (Pourcelot index)

A

Index of pulsatility and opposition to flow

DSM PHY (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions