Post on 15-May-2018
Accompanying text for
the slides in this lesson
can be found on pages 33
through 42 in the
textbook:
Lesson 07:
Ultrasound Transducers
This lesson contains 62 slides
plus 16 multiple-choice
questions.
Ultrasound Transducers
THE NUMBER OF ACOUSTIC LINES
IN A REAL TIME IMAGE:
PULSE REPETITION FREQUENCY
FRAME RATE
Ultrasound Transducers
PRF ÷ FRAME RATE = ACOUSTIC LINES
1000 Hz 10 Hz 100
1000 Hz 20 Hz 50
1500 Hz 10 Hz 150
1500 Hz 20 Hz 75
2000 Hz 10 Hz 200
2000 Hz 20 Hz 100
ACOUSTIC LINES = PRF ÷ FRAME RATE
Ultrasound Transducers
ACOUSTIC LINES = PRF ÷ FRAME RATE
DISPLAY
DEPTH
PRF CHANCE OF
DEPTH
AMBIGUITY
FRAME RATE ACOUSTIC
LINES
Increase Decrease Decrease ——–—-—- Decrease
Decrease Increase Increase —————- Increase
—————— —————— —————— Increase Decrease
—————— —————— —————— Decrease Increase
Question 1
For a real time image to be flicker-free, the minimum
image frame rate should be
15 Hz
1000 Hz
1 Hz
100 Hz
1 MHz
Page 34
Question 1
For a real time image to be flicker-free, the minimum
image frame rate should be
15 Hz
1000 Hz
1 Hz
100 Hz
1 MHz
Page 34
If the real time frame rate is 20 Hz, the
pulse repetition period is 1/20 second
image is updated every 1/1000 second
number of acoustic lines is 1000
number of acoustic lines is 20
image is updated every 1/20 second
Question 2
Page 34
If the real time frame rate is 20 Hz, the
pulse repetition period is 1/20 second
image is updated every 1/1000 second
number of acoustic lines is 1000
number of acoustic lines is 20
image is updated every 1/20 second
Question 2
Page 34
If the real time frame rate is increased but the lines
per frame are unchanged, what else must happen?
speed of sound increases
imaging depth increases
transducer frequency increases
the pulse repetition frequency decreases
imaging depth decreases
Question 3
Page 34
If the real time frame rate is increased but the lines
per frame are unchanged, what else must happen?
speed of sound increases
imaging depth increases
transducer frequency increases
the pulse repetition frequency decreases
imaging depth decreases
Question 3
Page 34
If the lines per frame changed but the imaging depth
remained the same, what else must have changed?
frame rate
pulse repetition period
pulse repetition frequency
duty factor
resolution
Question 4
Page 34
If the lines per frame changed but the imaging depth
remained the same, what else must have changed?
frame rate
pulse repetition period
pulse repetition frequency
duty factor
resolution
Question 4
Page 34
If the imaging depth is increased and the sector
angle and line density remain the same, what must
have taken place?
PRF increases
transducer frequency increases
frame rate decreases
PRP decreases
frame rate increases
Question 5
Page 34
If the imaging depth is increased and the sector
angle and line density remain the same, what must
have taken place?
PRF increases
transducer frequency increases
frame rate decreases
PRP decreases
frame rate increases
Question 5
Page 34
A real time transducer with a frame rate of 10 Hz produces
100 acoustic lines. If the PRF is NOT changed,
a higher frame rate will increase the line density
a frame rate of 20 Hz will produce 200 acoustic lines
a lower frame rate results in more updated images
per second
the pulse repetition period is 100 milliseconds
a frame rate of 20 Hz will produce 50 acoustic lines
Question 6
Page 34
A real time transducer with a frame rate of 10 Hz produces
100 acoustic lines. If the PRF is NOT changed,
a higher frame rate will increase the line density
a frame rate of 20 Hz will produce 200 acoustic lines
a lower frame rate results in more updated images
per second
the pulse repetition period is 100 milliseconds
a frame rate of 20 Hz will produce 50 acoustic lines
Question 6
Page 34
Which transducer configuration produced the image?
flat linear array
curved linear array
convex array
phased array
vector array
Question 7
Pages 35 and 36
Which transducer configuration produced the image?
flat linear array
curved linear array
convex array
phased array
vector array
Question 7
Pages 35 and 36
Which transducer configuration produced the image?
flat linear array
curved linear array
convex array
phased array
vector array
Question 8
Pages 39 and 40
Which transducer configuration produced the image?
flat linear array
curved linear array
convex array
phased array
vector array
Question 8
Pages 39 and 40
Which transducer configuration produced the image?
flat linear array
curved linear array
non-curved linear array
phased array
vector array
Question 9
Pages 37 and 38
Which transducer configuration produced the image?
flat linear array
curved linear array
non-curved linear array
phased array
vector array
Question 9
Pages 37 and 38
Which transducer configuration produced the image?
flat linear array
curved linear array
non-curved linear array
phased array
vector array
Question 10
Pages 39 and 40
Which transducer configuration produced the image?
flat linear array
curved linear array
non-curved linear array
phased array
vector array
Question 10
Pages 39 and 40
Dynamic focusing is possible
only with transducers with frequencies above 5 MHz
when the dynamic range is maximum
only with transducer arrays
with two-element CW Doppler probes
with single piezoelectric elements
Question 11
Page 41
Dynamic focusing is possible
only with transducers with frequencies above 5 MHz
when the dynamic range is maximum
only with transducer arrays
with two-element CW Doppler probes
with single piezoelectric elements
Question 11
Page 41
With phased array transducers, the transmitted sound
beam is swept by
mechanically sweeping the piezoelectric elements
mechanically rotating the piezoelectric elements
varying the timing of pulses to the individual
piezoelectric elements
varying the voltage of pulses to the individual
piezoelectric elements
varying the frequency of pulses to the individual
piezoelectric elements
Question 12
Page 39
With phased array transducers, the transmitted sound
beam is swept by
mechanically sweeping the piezoelectric elements
mechanically rotating the piezoelectric elements
varying the timing of pulses to the individual
piezoelectric elements
varying the voltage of pulses to the individual
piezoelectric elements
varying the frequency of pulses to the individual
piezoelectric elements
Question 12
Page 39
The use of a water path permits
the use of increased output power from the transducer
higher frequencies to be used
higher duty factors
higher pulse repetition frequencies to be used
better visualization of superficial structures
Question 14
Page 42
The use of a water path permits
the use of increased output power from the transducer
higher frequencies to be used
higher duty factors
higher pulse repetition frequencies to be used
better visualization of superficial structures
Question 14
Page 42
Which element arrangement would only be used in
mechanically steered transducers?
phased linear array
convex array
non-curved sequenced array
sequenced array
annular array
Question 15
Page 41
Which element arrangement would only be used in
mechanically steered transducers?
phased linear array
convex array
non-curved sequenced array
sequenced array
annular array
Question 15
Page 41
The advantage of an annular array over a single
element transducer is
reduced output power from the transducer
higher frequencies are possible
improved axial resolution
greater depth of focus
lower cost
Question 16
Page 41
The advantage of an annular array over a single
element transducer is
reduced output power from the transducer
higher frequencies are possible
improved axial resolution
greater depth of focus
lower cost
Question 16
Page 41