Ultrasound Display Modes (A-mode and B-mode)
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1
What is the Y-axis of an A-mode display?
Amplitude
2
What is the X-axis of an A-mode display?
Depth
3
A-mode depth is derived from what?
Time of flight
4
In A-mode, a strong echo makes what kind of spike?
Tall
5
Which specialty still uses A-mode for accurate depth measurements?
Ophthalmology
6
On A-mode, what appears between the walls of a cystic mass?
Flat line
7
On A-mode, where does a solid (echogenic) mass show spikes?
Throughout
8
What is the single beam path sampled in A-mode called?
Scan line
9
Display mode where echo amplitude is shown as the brightness of a dot
B-mode
10
What is on the Z-axis of a B-mode display?
Amplitude
11
What is on the Y-axis of a B-mode display?
None
12
What is on the X-axis of a B-mode display?
Depth
13
B-mode was the first form of what imaging?
Grayscale
14
In B-mode, a strong echo is mapped to what shade?
Bright white
15
In B-mode, a weak echo is mapped to what shade?
Dark gray
16
In B-mode, the absence of signal is mapped to what shade?
Almost black
17
What is the main advantage of early B-mode scanning?
Large field of view
18
Early B-mode static scanning had poor what resolution?
Temporal
19
Early B-mode image quality depended heavily on what?
Sonographer skill
20
Display mode showing reflector position versus time
M-mode
21
What is on the X-axis of an M-mode display?
Time
22
What is on the Y-axis of an M-mode display?
Depth
23
M-mode is mainly used in which specialty?
Echocardiography
24
What does TM-mode stand for?
Time-motion
25
What does PM-mode stand for?
Position-motion
26
On M-mode, a straight horizontal line means the reflector is what?
Stationary
27
Only display mode that shows reflectors changing location over time
M-mode
28
How many crystals does a mechanical transducer have?
One
29
What shape is the crystal in a mechanical transducer?
Disc
30
How is a mechanical transducer steered?
Mechanically
31
How is a mechanical transducer focused?
Fixed
32
External device used for fixed focusing
Acoustic lens
33
What physically moves the crystal in a mechanical transducer?
Motor
34
What image shape does a mechanical transducer make?
Sector
35
A defective crystal in a single-crystal mechanical transducer causes what?
Entire image lost
36
Moving parts in mechanical transducers cause what artifact?
Motion
37
Mechanical transducers have limited what resolution?
Temporal
38
Mechanical transducers produce excessive what lobes?
Grating
39
Group of closely spaced elements, each with its own electrical connection
Array
40
Annular array elements are arranged as concentric what?
Rings
41
How is an annular array steered?
Mechanically
42
How is an annular array focused?
Electronically
43
Can an annular array be steered electronically?
No
44
What is the primary advantage of an annular array?
Multiple focal zones
45
Which annular rings are used for shallow focus?
Inner
46
Which annular rings are used for deep focus?
Outer
47
What image shape does an annular array make?
Sector
48
A defective ring in an annular array causes what dropout?
Horizontal band
49
Which transducer is steered mechanically with a fixed focus?
Mechanical
50
Which transducer is steered mechanically and focused electronically?
Annular array
51
Exciting groups of elements in a specific pattern to scan a region
Sequencing
52
Does a linear sequential array fire all elements or groups?
Groups
53
What image shape does a linear sequential array make?
Rectangular
54
A linear sequential image is no wider than what?
Transducer
55
Beams from a linear sequential array travel in what direction relative to each other?
Parallel
56
How is a modern linear sequential array focused?
Electronically
57
A defective element in a linear sequential array causes what dropout?
Vertical band
58
The rate at which the full firing sequence repeats determines what?
Frame rate
59
A linear sequenced array is mainly used for what?
Vascular
60
A curved sequenced array is mainly used for what?
Abdominal
61
For transmit focusing, which elements fire first?
Outer
62
What firing pattern focuses the beam?
Curved
63
What firing pattern steers the beam?
Sloped
64
Firing all elements at the same time produces what kind of beam?
Unfocused
65
What shape is a steered color Doppler box on a linear array?
Parallelogram
66
How do arrays steer the beam?
Electronically
67
How do arrays focus the beam?
Electronically
68
The amount of time shift needed to make two waves align
Phase difference
69
Arrays steer and focus using time delays measured in what unit?
Nanoseconds
70
Time delays between the excitation pulses applied to array elements
Phase delays
71
Phase delays for steering are separated by about how many nanoseconds?
10
72
On an array, who selects the transmit focus depth?
Sonographer
73
Changing the delay sequence moves what?
Focal depth
74
What is the advantage of multiple focal zones?
Better lateral resolution
75
What is the disadvantage of multiple focal zones?
Decreased temporal resolution
76
What do multiple focal zones do to frame rate?
Decrease it
77
3 focal zones require how many times as many pulses?
3
78
Which focusing technique decreases frame rate?
Multiple transmit focal zones
79
Automatic focusing during reception with time delays that change continuously with depth
Dynamic receive focusing
80
Is dynamic receive focusing controlled by the operator?
No
81
At what depths is dynamic receive focusing applied?
All
82
Does dynamic receive focusing slow the frame rate?
No
83
What is another name for dynamic receive focusing?
Dynamic aperture
84
Combination of active element, wire, and system electronics
Channel
85
Dynamic aperture uses more elements for which echoes?
Deep
86
Dynamic aperture uses fewer elements for which echoes?
Shallow
87
Dynamic aperture keeps the beam what?
Narrow
88
Dynamic aperture improves which resolution?
Lateral
89
Dynamic aperture helps reduce which lobes?
Side lobes
90
System component that creates the electronic delay patterns for transmit and receive
Beam former
91
During transmission, the beam former coordinates the signals sent to what?
Each active element
92
During reception, the beam former sets the time delays for what?
Dynamic receive focusing
93
The beam former accepts a wide range of frequencies, meaning it is what?
Broadband
94
Beam former advantages are stability, broadband, and what?
Programmability
95
Beam former component that protects the receiver from powerful transmit signals
Transmit-receive switch
96
What does the transmit-receive switch protect?
Receiver
97
What is a phased array mainly used for?
Cardiac
98
A phased array's small footprint lets it image between what?
Ribs
99
What is the frequency range of a phased array?
2–8 MHz
100
A phased array goes up to what frequency for pediatric cardiac?
12 MHz
101
How is a phased array steered and focused?
Electronically
102
What image shape does a phased array make?
Sector
103
How many elements fire for each scan line in a phased array?
All
104
A phased array is also called what kind of probe?
Sector probe
105
A defective crystal in a phased or convex array causes what dropout?
Vertical band
106
Convex array elements are arranged in what shape?
Arc
107
Are convex array beam lines parallel?
No
108
Does a convex array fire all elements or groups?
Groups
109
What is the frequency range of a convex array?
2–10 MHz
110
What image shape does a convex array make?
Blunted sector
111
How is a convex array steered and focused?
Electronically
112
A convex array is mainly used for what scans?
Abdominal
113
A linear phased array is designed for what applications?
Vascular
114
What is the frequency range of a linear phased array?
5–18 MHz
115
What image shape does a linear phased array make?
Rectangular
116
How is a linear phased array steered and focused?
Electronically
117
A linear phased array steered for Doppler makes what shape?
Parallelogram
118
What is the frequency range of a hockey stick probe?
5–9 MHz
119
What is the footprint of a hockey stick probe?
25 mm
120
A hockey stick probe is used for vascular and what?
Small parts
121
Linear probe frequency ranges start at what MHz?
5
122
A vector array combines linear sequential with what array?
Linear phased
123
What is the frequency range of a vector array?
2.5–4.0 MHz
124
What image shape does a vector array make?
Trapezoidal
125
How is a vector array steered and focused?
Electronically
126
A vector array is useful for scanning what organ?
Kidney
127
Which transducer makes a trapezoidal image?
Vector
128
Which transducer makes a blunted sector image?
Convex
129
Which transducer makes a pie-shaped image for cardiac?
Phased array
130
What is the frequency range of endocavity probes?
3.5–11.5 MHz
131
What is the frequency range of a TEE probe?
3–10 MHz
132
A CW non-imaging Doppler probe is also called what?
Pedoff
133
Does a Pedoff probe produce an image?
No
134
How is a Pedoff probe steered?
Manually
135
How is a Pedoff probe focused?
Fixed
136
What is the frequency range of a Pedoff probe?
2–8 MHz
137
A Pedoff probe is used to measure what?
Blood flow
138
What is the frequency range of transluminal probes?
20–40 MHz
139
Transluminal probes fit on the tip of what?
Catheter
140
Which probe is 3–10 MHz?
TEE
141
Which probe is 2.5–4.0 MHz?
Vector
142
Which probe is 5–18 MHz?
Linear phased
143
Which probe is 5–9 MHz?
Hockey stick
144
Which probe is 2–10 MHz?
Convex
145
Which probe is 3.5–11.5 MHz?
Endocavity
146
Which probe is 20–40 MHz?
Transluminal
147
Secondary lobes cause image clutter and degrade which resolution?
Lateral
148
Low-intensity secondary lobes produced by all transducers, directly alongside the main beam
Side lobes
149
Secondary lobes found only in arrays, at a large angle from the main beam
Grating lobes
150
Which transducers produce side lobes?
All
151
Grating lobes occur only in what?
Arrays
152
Where are side lobes located?
Alongside the main beam
153
Where are grating lobes located?
Large angle from main beam
154
Grating lobes occur because the transducer is what?
Diced
155
Grating lobes can create what kind of images?
Ghost images
156
Higher frequency reduces which lobes?
Side lobes
157
Which array type has the biggest grating lobe problem?
Linear phased
158
Using very thin, closely spaced elements to eliminate grating lobes
Subdicing
159
With subdicing, elements are no more than how far apart?
½ wavelength
160
Subdicing eliminates what between crystals?
Cross talk
161
Subdicing reduces which lobes?
Grating
162
Varying the strength of the voltage spikes applied to the crystals to reduce lobes
Apodization
163
Apodization reduces which lobes?
Both
164
Which component performs apodization?
Beam former
165
Combination of axial and lateral resolution
Detail resolution
166
Detail resolution is also called what?
Spatial resolution
167
Detail resolution depends primarily on what?
Transducer
168
Ability to distinguish structures based on differences in brightness or echogenicity
Contrast resolution
169
Contrast resolution is limited by what?
Bit depth
170
Ability to distinguish changes over time
Temporal resolution
171
What is the major limit of temporal resolution?
Frame rate
172
Every factor that lowers frame rate does what to temporal resolution?
Lowers it
173
What does deeper imaging do to temporal resolution?
Lowers it
174
What does a wider sector do to temporal resolution?
Lowers it
175
What do more focal zones do to temporal resolution?
Lowers it
176
What does higher line density do to temporal resolution?
Lowers it
177
In color Doppler, what else lowers temporal resolution?
Packet size
178
Frame rate is determined by depth, lines of sight, and what?
Speed of sound
179
Frame rate is determined by speed of sound, lines of sight, and what?
Depth
180
Frame rate is determined by speed of sound, depth, and what?
Lines of sight
181
Number of images produced per second
Frame rate
182
What are the units of frame rate?
Hertz
183
For a higher frame rate, image shallow or deep?
Shallow
184
For a higher frame rate, use single or multiple focus?
Single
185
For a higher frame rate, use a narrow or wide sector?
Narrow
186
For a higher frame rate, use low or high line density?
Low
187
How many pulses does each scan line require?
One
188
Maximum frame rate is ultimately limited by what?
Speed of sound
189
What is the speed of sound in soft tissue?
1540 m/s
190
Faster-moving structures require a higher what?
Frame rate
191
What is the relationship between pulses per frame and frame rate?
Inverse
192
What is the frame rate equation?
\$FR=\frac{c}{2dN}\$
193
In the frame rate equation, what is c?
Speed of sound
194
In the frame rate equation, what is d?
Depth
195
In the frame rate equation, what is N?
Lines of sight per frame
196
Which two frame rate variables can the sonographer control?
Depth and lines per frame
197
Increasing depth does what to frame rate?
Decreases it
198
Increasing lines of sight does what to frame rate?
Decreases it
199
Halving the depth does what to frame rate?
Doubles it
200
Doubling the depth does what to frame rate?
Halves it
201
What is the relationship between depth and frame rate?
Inverse
202
Spacing between scan lines in an image
Line density
203
Line spacing is usually set by whom?
Manufacturer
204
High line density means more or fewer pulses per frame?
More
205
High line density gives a higher or lower frame rate?
Lower
206
High line density gives superior what resolution?
Spatial
207
Low line density gives superior what resolution?
Temporal
208
What is the advantage of high line density?
Better spatial resolution
209
A wider sector requires more or fewer pulses per frame?
More
210
A 30° sector with 1 line per degree needs how many pulses?
30
211
Time for sound to travel 1 cm and back in soft tissue
13 μs
212
Shallow imaging has a short or long go-return time?
Short
213
Deep imaging gives a higher or lower frame rate?
Lower
214
Excellent temporal resolution is compared to a good what?
Movie
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