Physics Ii

Front 1

What is the hydrostatic pressure within the arterial circulation at heart level when the patient is standing?

Back 1

0 mmHg

Front 2

What is the hydrostatic pressure within the arterial circulation at head level when the patient is standing?

Back 2

- 30 mmHg

Front 3

What is the hydrostatic pressure within the arterial circulation at waist level when the patient is standing?

Back 3

50 mmHg

Front 4

What is the hydrostatic pressure within the arterial circulation at knee level when the patient is standing?

Back 4

75 mmHg

Front 5

What is the hydrostatic pressure within the arterial circulation at ankle level when the patient is standing?

Back 5

100 mmHg

Front 6

True/False:

When standing, hydrostatic pressure depends upon whether the measurement is made above or below the heart level.

Back 6

True

Front 7

What is the arterial pressure measured in the toe of an upright patient with an arterial blood pressure of 140 mmHg (circulatory pressure)?

Back 7

240 mmHg

circulatory + hydrostatic = measured pressure

*140 mmHg + 100 mmHg = 240 mmHg

Front 8

What is the arterial pressure measured at the knee of an upright patient with an arterial blood pressure of 140 mmHg (circulatory pressure)?

Back 8

215 mmHg

circulatory + hydrostatic = measured pressure

*140 mmHg + 75 mmHg = 215 mmHg

Front 9

What is the arterial pressure measured at the waist of an upright patient with an arterial blood pressure of 140 mmHg (circulatory pressure)?

Back 9

190 mmHg

circulatory + hydrostatic = measured pressure

*140 mmHg + 50 mmHg = 190 mmHg

Front 10

What is the arterial pressure measured at the upper arm of an upright patient with an arterial blood pressure of 140 mmHg (circulatory pressure)?

Back 10

140 mmHg

circulatory + hydrostatic = measured pressure

*140mmHg + 0 mmHg = 140 mmHg

Front 11

What is the arterial pressure measured at the head of an upright patient with an arterial blood pressure of 140 mmHg (circulatory pressure)?

Back 11

110 mmHg

circulatory + hydrostatic = measured pressure

*-30 mmHg + 140 mmHg = 110 mmHg

Front 12

Normally, what happens to venous flow in the legs during inspiration?

a) increase

b) decrease

c) no change

Back 12

b) decreases

Front 13

All of the following occur during expiration except?

a) venous return to the heart decreases

b) venous flow in the legs increases

c) abdominal pressure increases

d) the diaphragm rises into the thoracic cavity

Back 13

c) abdominal pressure increases

*during expiration, abdominal pressure decreases

Front 14

What is the hydrostatic pressure at all locations within the arterial circulation of a patient in supine position?

Back 14

0 mmHg

*all arteries are at the same level as the heart in supine position, therefore, the body is 0 mmHg

Front 15

What is the arterial pressure at the knee of a supine patient with an arterial blood pressure of 140 mmHg?

Back 15

140 mmHg

*since the knee is at heart level in supine position, the hydrostatic pressure is 0 mmHg

circulatory + hydrostatic = measured pressure

*140 mmHg + 0 mmHg = 140 mmHg

Front 16

What is the arterial pressure in the carotid artery of the neck of a supine patient with an arterial blood pressure of 140 mmHg?

Back 16

140 mmHg

*since the neck is at the same level as the heart in supine position, the hydrostatic pressure is 0 mmHg

circulatory + hydrostatic = measured pressure

*140 mmHg + 0 mmHg = 140 mmHg

Front 17

True/False:

Flow is also called volume flow rate.

Back 17

True

Front 18

__________ indicates the volume of blood moving during a particular time.

Back 18

Flow (L/min)

Front 19

__________ measurements answer the question: "how much?"

Back 19

Flow (L/min)

Front 20

_____________ indicates the speed or swiftness of a fluid moving from one location to another.

Back 20

Velocity (cm/s)

Front 21

______________ answers the question: "how fast?"

Back 21

Velocity (cm/s)

Front 22

_______________ flow occurs when blood moves with a variable velocity and blood accelerates and decelerates as a result of cardiac contraction.

Back 22

Pulsatile flow

*arterial contraction

Front 23

True/False:

Blood accelerates and decelerates as a result of cardiac contraction and respiration.

Back 23

True

Front 24

True/False:

Pulsatile flow commonly appears in the venous circulation.

Back 24

False

*arterial

Front 25

____________ flow occurs when blood moves with a variable velocity and blood accelerates and decelerates as a result of respiration.

Back 25

Phasic flow

*venous circulation

Front 26

True/False:

Blood accelerates and decelerates as a result of respiration and cardiac contraction.

Back 26

True

Front 27

True/False:

Phasic flow often appears in the venous circulation.

Back 27

True

Front 28

__________ flow occurs when a fluid moves at a constant speed or velocity.

Back 28

Steady flow

Front 29

___________ flow is present in the venous circulation when individuals stop breathing for a brief moment.

Back 29

Steady flow

Front 30

______________ flow is when the flow streamlines are aligned and parallel.

Back 30

Laminar flow

Front 31

______________ flow is characterized by layers of blood that travel at individual speeds.

Back 31

Laminar flow

Front 32

True/False:

Laminar flow patterns are commonly found in normal physiologic states.

Back 32

True

Front 33

True/False:

Laminar flow patterns are plug flow or parabolic flow.

Back 33

True

Front 34

______________ flow is characterized by chaotic flow patterns in many different directions and at many speeds.

Back 34

Turbulent flow

Front 35

In ______________ flow, the streamlines are often obliterated.

Back 35

Turbulent flow

Front 36

True/False:

Turbulent flow profiles are chaotic.

Back 36

True

Front 37

In a stenotic vessel, where is the highest pressure located?

a) before the stenotic area

b) in the stenotic area

c) after the stenotic area

Back 37

a) before the stenotic area

Front 38

In a stenotic vessel, where is the lowest pressure located?

a) before the stenotic area
b) in the stenotic area
c) after the stenotic area

Back 38

b) in the stenotic area

Front 39

In a stenotic vessel, where is the maximum velocity located?

a) before the stenotic area
b) in the stenotic area
c) after the stenotic area

Back 39

b) in the stenotic area

Front 40

In a stenotic vessel, where is the most turbulent flow located?

a) before the stenotic area
b) in the stenotic area
c) after the stenotic area

Back 40

c) after the stenotic area (downstream)

Front 41

True/False:

In the circulatory system, the resistance vessels are called arterioles.

Back 41

True

Front 42

Pressure related to the weight of blood pressing on a vessel measured at a height above or below heart level, is called?

Back 42

Hydrostatic pressure

Front 43

True/False:

When supine, hydrostatic pressure is zero everywhere since all vessels are at the same level as the heart.

Back 43

True

Front 44

During _______________, the diaphragm descends. Venous return to the heart increases. Venous flow in the legs decreases.

Back 44

inspiration

Front 45

During __________________, the diaphragm ascends. Venous return to the heart decreases. Venous flow in the legs increases.

Back 45

expiration

Front 46

During __________________, the diaphragm moves downward toward the abdomen.

Back 46

inspiration

Front 47

During _____________, thoracic pressure decreases and abdominal pressure increases.

Back 47

inspiration

Front 48

During _______________, venous return to the heart increases and venous flow to the legs decreases.

Back 48

inspiration

Front 49

During _______________, the diaphragm moves upward into the thorax.

Back 49

expiration

Front 50

During _______________, the thoracic pressure increases and the abdominal pressure decreases.

Back 50

expiration

Front 51

During _____________, venous return to the heart decreases and venous flow to the legs increases.

Back 51

expiration

Front 52

True/False:

Venous flow in the legs correlates with the movement of the diaphragm.

Back 52

True

Front 53

True/False:

Downward movement of the diaphragm (inspiration) decreases venous flow in the legs.

Back 53

True

Front 54

True/False:

Upward movement of the diaphragm (expiration) increases venous flow in the legs.

Back 54

True

Front 55

True/False:

When venous flow in the leg decreases, venous return to the heart decreases.

Back 55

False

*venous flow in legs decrease while venous return to the heart increases

Front 56

True/False:

When venous flow in the leg increases, venous return decreases.

Back 56

True

Front 57

True/False:

The Doppler principle is used to measure red blood cell velocities.

Back 57

True

Front 58

True/False:

Blood cells moving toward the transducer reflect sound with a higher frequency.

Back 58

True

Front 59

True/False:

Blood cells moving away from the transducer reflect sound with a higher frequency.

Back 59

False

*lower frequency

Front 60

What is the Doppler Equation?

Back 60

Doppler shift = 2(blood velocity)(transducer frequency)(cos theta)/propagation speed

Front 61

True/False:

The Doppler shift is directly related to velocity.

Back 61

True

*frequency

Front 62

True/False:

When the blood cell velocity doubles, the Doppler frequency doubles.

Back 62

True

Front 63

True/False:

The y-axis of a Doppler Spectrum represents Doppler shift (kHz) or velocity.

Back 63

True

Front 64

True/False:

The Doppler Shift is directly proportional to the transducer frequency.

Back 64

True

Front 65

True/False:

When the transmitted frequency doubles, the Doppler frequency doubles.

Back 65

True

Front 66

True/False:

Calculated velocities from measured Doppler Shifts will be identical, regardless of the transducer frequency.

Back 66

True

Front 67

True/False:

Doppler Shift is indirectly related to velocity and transducer frequency.

Back 67

False

*Doppler Shift is directly related to velocity and transducer frequency

Front 68

The ______________ _________ represents 100% of the true velocity when blood flow is parallel to the sound beam.

Back 68

Doppler Shift

Front 69

True/False:

When blood flow is not parallel to the sound beam, meaning there is an angle, Doppler will measure something less than the true velocity.

Back 69

True

Front 70

True/False:

Doppler Shift is directly related to cosine theta.

Back 70

True

Front 71

True/False:

When the cosine doubles, the Doppler frequency doubles.

Back 71

True

Front 72

True/False:

The cosine increases as angles approach zero degrees.

Back 72

True

Front 73

What is the cosine of zero degrees?

Back 73

1.0

Front 74

What is the cosine of 90 degrees?

Back 74

0

Front 75

What is the cosine of 180 degrees?

Back 75

- 1.0

Front 76

True/False:

At angles other than zero degrees and 180 degrees, only a portion of the true velocity is measured.

Back 76

True

Front 77

True/False:

Blood cells in adjacent arteries and veins typically flow in opposite directions.

Back 77

True

Front 78

True/False:

Continuous wave Doppler uses one transducer crystal.

Back 78

False

*CW uses two crystals. One that transmits. One that receives.

Front 79

True/False:

For Continuous Wave Doppler, all the velocities within the overlap region are measured.

Back 79

True

Front 80

With ______________ wave Doppler, velocities are measured along the entire sound beam.

Back 80

Continuous wave Doppler

Front 81

True/False:

A dedicated CW Doppler probe (pedoff) is small and has only two elements. Anatomic imaging cannot be performed.

Back 81

True

Front 82

True/False:

Dedicated CW transducers (pedoff) have increased sensitivity that can detect low amplitude reflections and small Doppler shifts.

Back 82

True

Front 83

______________ wave Doppler measures velocity in a small region, the sample volume.

Back 83

Pulsed wave Doppler

Front 84

For ____________ wave Doppler spectrum, velocities are measured from the sample volume.

Back 84

Pulsed wave Doppler

Front 85

True/False:

Aliasing artifact appears only with Continous wave Doppler.

Back 85

False

*aliasing only occurs with Pulsed wave Doppler

Front 86

The __________ __________ is the highest Doppler frequency or velocity that can be measured without the appearance of aliasing.

Back 86

Nyquist Limit

Front 87

Aliasing appears when the Doppler shift exceeds the ______________ _____________.

Back 87

Nyquist limit

Front 88

Aliasing appears when the _____________ __________ exceeds the Nyquist limit.

Back 88

Doppler shift

Front 89

Aliasing is eliminated by increasing or decreasing the Doppler shift or ________________ _____________.

Back 89

Nyquist limit

Front 90

When there is less aliasing, blood velocity is _____________, the transducer frequency is ____________, and there is a _______ PRF (shallow gate).

Back 90

slower blood velocity

lower frequency transducer

high PRF

Front 91

When there is more aliasing, blood velocity is ___________, the transducer frequency is ____________, and there is a ______ PRF (deep gate).

Back 91

faster blood velocity

higher frequency transducer

low PRF

Front 92

A Doppler spectrum with aliasing has a ________ Nyquist limit because the sample volume is __________.

Back 92

low Nyquist limit

deep sample volume

Front 93

A Doppler spectrum without aliasing has a ________ Nyquist limit because the sample volume is __________.

Back 93

high Nyquist limit

shallow sample volume

Front 94

True/False:

The Doppler shift is directly related to the transducer frequency.

Back 94

True

Front 95

True/False:

Lower frequency transducers create lower Doppler shifts that are less likely to exceed the Nyquist limit and alias.

Back 95

True

Front 96

True/False:

Eliminating aliasing improves the ability to measure the maximum velocity with Doppler.

Back 96

True

Front 97

True/False:

Pulsed wave Doppler exhibits aliasing with high-velocity flow.

Back 97

True

Front 98

True/False:

Pulsed wave Doppler never aliases.

Back 98

False

*CW Doppler never aliases

Front 99

True/False:

By adjusting the scale or creating a shallower view, the Nyquist limit will increase eliminating aliasing.

Back 99

True

Front 100

True/False:

Lowering the transducer frequency will decrease the Doppler shift eliminating aliasing.

Back 100

True

Front 101

True/False:

By zeroing the baseline shift, aliasing remains but display becomes more appealing.

Back 101

True

Front 102

______________ wave Doppler never aliases, but has range ambiguity.

Back 102

Continuous wave Doppler

Front 103

The _______ _________ of a Doppler spectrum is related to the number of blood cells.

Back 103

gray scale

Front 104

______________ wave Doppler has region overlap and unlimited maximum velocity.

Back 104

Continuous wave Doppler

Front 105

_______________ wave Doppler has range resolution and aliasing.

Back 105

Pulsed wave Doppler

Front 106

_______________ wave Doppler uses a sample volume and has a limited maximum velocity (nyquist limit).

Back 106

Pulsed wave Doppler

Front 107

A _____________ Doppler transducer has at least one crystal and lower sensitivity.

Back 107

Pulsed Doppler transducer

Front 108

A _____________ Doppler transducer has a dampened PZT, low Q-factor, and a wide bandwidth.

Back 108

Pulsed Doppler transducer

Front 109

A ______________ wave Doppler transducer has at least two crystals and higher sensitivity.

Back 109

Continuous wave Doppler transducer

Front 110

A _______________ wave Doppler transducer has an undampened PZT, high Q-factor, and a narrow bandwidth.

Back 110

Continuous wave Doppler transducer

Front 111

______________ wave Doppler has a normal incidence (90 degrees) and higher frequency which improves resolution.

Back 111

Pulsed wave Doppler

Front 112

_______________ wave Doppler is either 0 degrees or 180 degrees and has lower frequency which avoids aliasing.

Back 112

Continuous wave Doppler

Front 113

______________ Doppler measures mean velocity.

Back 113

Color Doppler

Front 114

_______________ Doppler measures peak velocity.

Back 114

Spectral Doppler (PW + CW)

Front 115

True/False:

In regards to the Color Map, the color on the top of the scale is towards the transducer, and the color on the bottom is away from the transducer.

Back 115

True

*normally red is towards, blue is away

Front 116

True/False:

With variance mode of a Color Map scale, the colors change side to side, as well as, up and down.

Back 116

True

*hint (side to side): L is for left side, left is for laminar flow. Right is turbulent flow.

Front 117

What does the black area in the center of the Color Map represent?

Back 117

zero Doppler shift

Front 118

Refer to images on pages:

Back 118

330 + 331 regarding Color Map

Front 119

True/False:

Color power Doppler is non-directional.

Back 119

True

Front 120

________ ___________ eliminates low frequency Doppler signals near the spectral baseline.

Back 120

Wall filter

Front 121

True/False:

Color 'bleeds' into moving anatomy with a high wall filter setting.

Back 121

False

*low wall filter setting

Front 122

True/False:

With high wall filters, low-velocity reflectors, such as tissue, are without color.

Back 122

True

Front 123

________________ is a special form of 'mirror image' artifact that appears on a spectral display.

Back 123

Crosstalk

Front 124

______________ flow has a well defined, clear window in spectral Doppler.

Back 124

Laminar flow

Front 125

In spectral broadening, the fill-in of the windows, is associated with ______________ flow.

Back 125

turbulent flow

Front 126

_______________ wave Doppler identifies the highest velocity jets anywhere along the length of the ultrasound beam.

Back 126

Continuous wave Doppler

Front 127

_______________ wave Doppler has range ambiguuity, higher sensitivity, and has good temporal resolution.

Back 127

Continuous wave Doppler

Front 128

_______________ wave Doppler accurately identifies the location of flow, has range resolution, and is subject to aliasing.

Back 128

Pulsed wave Doppler

Front 129

Which Doppler mode(s) measure peak velocity?

Back 129

PW and CW Doppler

Front 130

Which Doppler mode provides two-dimensional flow information directly on anatomic images?

Back 130

Color-flow Doppler

Front 131

Which Doppler mode is used with low velocity or small volume blood flow?

Back 131

Power mode Doppler

Front 132

__________-_________ Doppler has reduced temporal resolution due to multiple packets, is based on pulsed ultrasound, and is subject to aliasing.

Back 132

Color-flow Doppler

Front 133

Which Doppler mode measures mean velocity measurements?

Back 133

Color Doppler

Front 134

True/False:

Power Mode Doppler has greater sensitivity than Color-flow Doppler and the lowest temporal resolution.

Back 134

True

Front 135

__________-__________ Doppler is subject to flash artifact, not to aliasing.

Back 135

Power-mode Doppler

Front 136

True/False:

Power-mode Doppler does not acquire velocity measurements .

Back 136

True

Front 137

The Doppler effect is presented as a ____________ shift when the source and the receiver are in _______________.

Back 137

frequency shift

in motion relative to each other

Front 138

Starting from the same point, the sound source is moving toward the east at 12 mph and the receiver is moving toward the west at 10 mph. The Doppler shift is _________________. (+/-)

Back 138

negative

*because the source and receiver are moving farther apart

Front 139

Starting from the same point, the receiver is moving toward the west at 12 mph and the source is moving toward the west at 10 mph. The Doppler shift is _______________. (+/-)

Back 139

negative

*because the source and receiver are moving farther apart

Front 140

Doppler shift produces information about _______________.

Back 140

velocity

Front 141

At what angle between the sound beam and the direction of motion will the Doppler shift be the highest?

Back 141

0 degrees or 180 degrees

*beam and direction should be parallel

Front 142

At what angle between the sound beam and the direction of motion will the Doppler shift be closest to zero?

Back 142

90 degrees

*no Doppler frequency exists because the Cosine of 90 degrees is zero

Front 143

What is the difference between speed and velocity?

Back 143

direction

*speed has a magnitude. velocity has a magnitude and direction

Front 144

What is the current method of processing Doppler signals?

Back 144

Fast Fourier Transform FFT

*method of spectral analysis used for PW and CW

Front 145

_____________________ is the method of spectral analysis for Color-flow Doppler.

Back 145

Autocorrelation

Front 146

What is the typical range of Doppler shift found in diagnostic imaging examinations?

Back 146

between 20 Hz and 20 kHz (in audible range)

Front 147

The phenomenon where high velocities appear in the opposite direction is called?

Back 147

aliasing

Front 148

The frequency at which aliasing occurs is called?

Back 148

Nyquist limit

Front 149

The area of interrogation in a pulsed Doppler exam is called?

Back 149

sample volume

Front 150

True/False:

The higher the emitted frequency, the more likely a pulsed wave signal is to alias.

Back 150

True

Front 151

True/False:

Shallower sample volumes result in more aliasing.

Back 151

False

Front 152

True/False:

Only pulsed wave Doppler exams have a sample volume.

Back 152

True

Front 153

An 8 MHz transducer with a pulse repetition frequency of 5,000 Hz is imaging to a depth of 7 cm. What is the Nyquist frequency?

a) 4 MHz

b) 2.2 kHz

c) 2.5 dB

d) 3.5 Hz

Back 153

b) 2.2 kHz

*Nyquist limit is one-half of the PRF, 2.5 kHz or 2,500 Hz

Front 154

An 8 MHz transducer with a PRF of 5,000 Hz measures a Doppler shift of 7 kHz. The study is repeated with a 4 MHz transducer. What Doppler shift will be measured?

a) 4 Mhz

b) 3,500 Hz

c) 4 kHz

d) 3.5 dB

Back 154

b) 3,500 Hz

*measured Doppler shift is directly related to the transducer frequency

*if the transducer frequency is halved, the Doppler shift will be halved

Front 155

True/False:

Doppler shift is directly related to the transducer frequency.

Back 155

True

Front 156

True/False:

A successful Doppler exam cannot be performed on a severely anemic patient.

Back 156

False

*variations in RBC concentration will not affect the ability to successfully perform a Doppler exam

Front 157

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

Back 157

autocorrelation

Front 158

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

Back 158

Fast Fourier Transform FFT

Front 159

Which of the following terms is synonymous with spectral broadening?

Back 159

turbulent flow

Front 160

Which of the following is an advantage of a large packet size?

a) less aliasing

b) increased frame rate

c) improved lateral resolution

d) increased Doppler accuracy

Back 160

d) increased Doppler accuracy

*Doppler is more accurate with larger packets

Front 161

Why are dedicated CW Doppler transducers so sensitive?

a) absence of the matching layer

b) increased electrical conductance

c) absence of backing material

d) inclusion of demodulator

Back 161

c) absence of backing material

Front 162

True/False:

Continuous wave Doppler does not contain backing material.

Back 162

True

Front 163

True/False:

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

Back 163

False

*the vessel will have both the toward and away colors. The center of the lumen will be black.

Front 164

Color cannot appear when the angle between the direction of flow and sound is _________ degrees to the vessel.

Back 164

90 degrees

Front 165

The amount of color present on a Color-flow Doppler image can be controlled with the ___________-___________ gain setting.

Back 165

Color-flow gain

Front 166

______________ wave Doppler gain settings alter the gray scale content of a spectral display.

Back 166

Pulsed wave Doppler

Front 167

True/False:

Increasing the scale of a color Doppler image can eliminate aliasing.

Back 167

True

Front 168

True/False:

The wall filter removes the color from slowly moving reflectors such as blood cells and vibrating tissues.

Back 168

True

Front 169

___________ ___________ eliminate low velocity flows near the baseline of a Doppler spectrum.

Back 169

Wall filters

Front 170

True/False:

Increasing the velocity scale eliminates aliasing and removes color from low velocities on the image.

Back 170

True

Front 171

Portions of an image that are brighter than surrounding tissues, or tissues that appear brighter than normal, are called?

Back 171

Hyperechoic

Front 172

Portions of an image that are not as bright as surrounding tissues, or tissues that appear less bright than normal, are called?

Back 172

Hypoechoic

Front 173

An extreme form of hypoechoic, meaning entirely without echoes (echo-free), is called?

Back 173

Anechoic

Front 174

_______________ describes structures with equal echo brightness.

Back 174

Isoechoic

Front 175

A portion of tissue or an image that has similar echo characteristics throughout, is called?

Back 175

Homogeneous

Front 176

A portion of tissue or an image that has differing echo characteristics throughout, is called?

Back 176

Heterogeneous

Front 177

Describe the Six Assumptions of the imaging system.

Back 177

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

Front 178

True/False:

Reverberations resemble a ladder or Venetian blind.

Back 178

True

Front 179

_________________ are created when a sound wave bounces back and forth between two strong reflectors.

Back 179

Reverberations (artifact)

* The first two reflections are real, the others are artifacts

Front 180

True/False:

Reverberations are multiple, equally spaced reflections.

Back 180

True

Front 181

True/False:

Comet tail artifact appears when a sound wave bounces back and forth between two very closely spaced objects.

Back 181

True

*form of reverberation artifact

Front 182

True/False:

Shadows may provide valuable diagnostic information that helps to characterize tissue.

Back 182

True

Front 183

True/False:

Shadowing is entirely unrelated to the speed of sound in a medium.

Back 183

True

Front 184

True/False:

Shadows are hypoechoic regions that extend beneath structures with abnormally high attenuation.

Back 184

True

Front 185

True/False:

Edge shadows are created as sound beams refract and diverge along the edge of a curved structure.

Back 185

True

Front 186

True/False:

Enhancement is a hyperechoic region that extends beneath structures with abnormally low attenuation.

Back 186

True

Front 187

True/False:

Enhancement artifact is the opposite of shadowing.

Back 187

True

Front 188

True/False:

Enhancement artifact is related to the speed at which sound travels in a medium.

Back 188

False

*unrelated

Front 189

True/False:

Focal banding is a hyperechoic horizontal region at the depth of the focus.

Back 189

True

Front 190

True/False:

The Mirror artifact is always deeper than the true anatomy.

Back 190

True

Front 191

____________ image artifact appears as a replica of a true reflector.

Back 191

Mirror image artifact

Front 192

True/False:

Lobe artifact and refraction artifact degrades lateral resolution.

Back 192

True

Front 193

What are the two methods to eliminate lobes?

Back 193

subdicing

apodization

Front 194

True/False:

Side lobes and grating lobes diminish lateral resolution.

Back 194

True

Front 195

____________ resolution artifact creates one reflection on the image from two closely spaced reflectors.

Back 195

Axial Resolution

Front 196

True/False:

Curved or oblique reflectors redirect sound waves in directions other than back toward the transducer.

Back 196

True

Front 197

True/False:

High line density results in better Axial Resolution.

Back 197

False

*better Spatial Resolution

Front 198

True/False:

Low line density degrades Spatial Resolution.

Back 198

True

Front 199

True/False:

More lines on a monitor provide better Spatial Resolution.

Back 199

True

Front 200

True/False:

Fewer lines result in poor Axial Resolution.

Back 200

False

*poor Spatial Resolution

Front 201

True/False:

Higher pixel density results in better Axial Resolution.

Back 201

False

*better Spatial Resolution

Front 202

True/False:

Lower pixel density degrades Spatial Resolution.

Back 202

True

Front 203

When creating an ultrasound image, all of the following assumptions are made except?

a) sound travels in a straight line

b) sound travels at 1.54 km/s

c) the sound beam is extremely thin

d) all structures create reflections of equal magnitude

Back 203

d) all structures create reflections of equal magnitude

Front 204

True/False:

Reflections from bone are usually strong, whereas reflections from soft tissue are normally weak.

Back 204

True

Front 205

Which statement regarding Axial Resolution is incorrect?

a) axial resolution artifact is related to beam diameter

b) higher quality images are associated with smaller numbers

c) axial resolution may be reported in units of meters

d) numerically, axial resolution equals one-half the pulse length

e) too few reflectors appear on the image

Back 205

a) axial resolution artifact is related to beam diameter

*Axial Resolution is related to the length of the pulse NOT beam diameter

Front 206

True/False:

Axial Resolution is related to the length of the pulse.

Back 206

True

Front 207

An ultrasound pulse has a width of 4 mm, a length of 2 mm, and is produced by a transducer 3,000 times per second. What is the best estimate of the systems Axial Resolution?

a) 4 mm

b) 2 mm

c) 1 mm

d) 1,500 Hz

Back 207

c) 1 mm

* axial resolution is equal to approximately one-half of the pulse length.

Front 208

Which of the following statements is true about lateral resolution?

a) it is also called angular, transverse, and depth resolution

b) it is reported in units of time

c) it is the same at all depths

d) it can be improved by focusing

Back 208

d) it can be improved by focusing

*lateral resolution (mm) depends upon the width of the ultrasound pulse

Front 209

True/False:

Lateral Resolution depends upon the width of the ultrasound pulse.

Back 209

True

Front 210

True/False:

Focusing narrows the beam width, improving Lateral Resolution.

Back 210

True

Front 211

All of the following artifacts result in the placement of too many echoes on the image except?

a) shadowing

b) reverberation

c) mirror image

d) grating lobes

Back 211

a) shadowing

Front 212

Which of the following determines the spatial resolution of a display?

a) number of pixels

b) number of lines on display

c) number of bits per pixel

d) spatial pulse length

Back 212

b) number of lines on display

*spatial resolution is determined by the number of horizontal lines on the display

Front 213

True/False:

Spatial Resolution is determined by the number of horizontal lines on the display.

Back 213

True

Front 214

Which of the following determines the spatial resolution of a digital display?

a) number of pixels

b) number of lines on display

c) number of bits per pixel

d) spatial pulse length

Back 214

a) number of pixels

*with digital display, spatial resolution is determined by the pixel density

Front 215

Which artifact produces an image with an incorrect number of reflectors?

a) propagation speed error

b) multipath

c) enhancement

d) side lobes

Back 215

d) side lobes

*side lobe artifact places a second echo on an image from a single structure

Front 216

True/False:

Mirror image artifacts always appear deeper than the true anatomy.

Back 216

True

Front 217

Which artifact is unrelated to the dimensions of an ultrasound pulse?

a) lateral resolution

b) depth resolution

c) slice thickness

d) refraction

Back 217

d) refraction

*refraction is not related to the shape of a sound pulse

Front 218

True/False:

Refraction artifact depends upon a sound wave striking a boundary with oblique incidence when the tissue on either side of the boundary are dissimilar.

Back 218

True

Front 219

True/False:

It is common to visualize artifacts when the dimension of the sound beam is larger than the reflector's dimension.

Back 219

True

*artifacts are likely to occur when the beam is larger than the reflector in the body

Front 220

Two reflections, one true and one artifact, are displayed on an ultrasound image. In the body, only one anatomic structure is present. The correct reflection and the artifact are found side by side. What is the most likely cause of this artifact?

a) mirror image

b) grating lobe

c) enhancement

d) multipath

Back 220

b) grating lobe

Front 221

Two distinct reflections are observed on an image, but they actually arise from a single anatomic structure. The artifact is positioned deeper than the correct reflection. What is the most likely cause of this artifact?

a) grating lobe

b) side lobe

c) refraction

d) mirror image

Back 221

d) mirror image

Front 222

Which one of these artifacts does not result from multiple reflections?

a) comet tail

b) reverberations

c) ring down

d) enhancement

Back 222

d) enhancement