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WorksheetsTemporal resolution and Frame rate
Total questions: 111
Worksheet time: 1hrs 28mins
Image is created with multiple __ __ automatically
(a)
Image is created with multiple SCAN LINES automatically .
This process is repeated several times per second
(a)
Once the entire array of elements have been fired, the system creates an image of the cross-section of interest, called a (a)
The production of a motion picture (movie type). (a) displayed in a rapid fashion to give the impression of constant motion
The ___ ___ per second determines TEMPORAL RESOLUTION
(a)
The FRAME RATE per second determines __ __
(a)
The images are continuously repeated and updated at a certain __ __.
(a)
Images displayed one frame at a time in a process called __ __
(a)
The systems ability to create numerous frames each second
(a)
Frame rate is determined by two factors:
Sound speed in the medium
The period
The frequency
The depth of imaging
Frame rate is expressed in (a)
(a) pertains to "accuracy in time", describes the ability to precisely position moving structures from instant to instant
When is temporal resolution excellent?
When frame rate is low
When frame is medium
When frame rate is high
All of the above
Temporal resolution is determined by the (a)
Displaying a (a) number of images improves temporal resolution
Displaying (a) images reduces the frame rate
Temporal resolution is expressed in (a)
A (a) is a single image created after all the elements in the array have been fired
it is the time it takes to create a single image OR the time to create a single frame.
(a)
it is the number of frames (single images) created per second
(a)
Frame rate is (a) related to the frame time
Which of the following is NOT a correct equation for the relation between frame rate and frame time?
Frame rate = 1/frame time
Frame time=1/frame rate
Time frame X frame time = 1
Frame rate = time frame x 1
(a) pulse represents one scan line
Each scan line represents a (a) element or a group of elements in a particular position in the array
__ __ require additional pulses per line
(a)
The (a) pulses needed, the lower the frame rate
The (a) pulses needed, the higher the frame rate.
What determines the number of pulses that can be sent per second?
(a)
PRF depends on the (a)
When depth is changed, or number of focal zones is increased, (a) will adjust automatically.
When an ultrasound system creates an image in 1/10 of a second, the frame rate is:
100 Hz
10 Hz
1 Hz
1000 Hz
Which of the following are the two sonographer controlled settings that affect frame rate?
Speed of sound in the medium
Imaging depth
Number of pulses per frame
Period
Which of the following is NOT a factor affecting the frame rate?
PRF
Imaging depth
Number of lines
PRP
Number of focal zones
Depth has a major influence in the frame rate, as well as the width of the scanning area.
True
False
(a) = # of focuses x lines per frame x frame rate
IF the number of focuses is 1, and the number of lines is 100, and the frame rate is 30, what is the PRF?
300
2000
500
3000
If focal zones are doubled, then the PRF will (a)
Depth, width of scan area, number of focal zones, number of Lines, PRF, and frequency are all factors affecting the (a)
What is time for the factors affected by the frame rate limited to?
Frequency
Period
Wavelength
Speed of sound in the medium
Standard speed of sound is 1.54 mm/us
In order to obtain a frame rate (per second) all the elements MUST be played (a) this time period
That means, the depth, the number of focal zones, the number of lines and the frame rate must occur considering the speed of sound as a (a)
Depth of scan area (cm) x # of focuses x lines per frame x frame rate must NOT be greater than (a)
Whenever the number resulting of multiplying the variables
is larger than (a) (see example in your Handout), the system will automatically adjust the Frame Rate first, and then any other variable
Is the ability to locate the position of moving targets from instant to instant, like in a movie
(a)
What are the two main factors from the system that influence temporal resolution:
Imaging depth
Number of pulses per frame
Speed of sound in that medium
Frequency
More images per second = (a) frames per second, which leads to better temporal resolution
Shallower image depth = (a) frame rate and better temporal resolution
Fewer pulses = (a) frame rate and better temporal resolution
Which two factors limit frame rate?
Period
PRF
Speed of sound in the medium
Depth of view
Which of the following best describes an instance when temporal resolution is high?
Field of view is increased
High line density
Frame rate is high
Number of focal zones is increased
Which of the following best describes an instance when temporal resolution is high?
Low line density
Frame rate is low
Field of view is increased
Number of focal zones is increased
Which of the following best describes an instance when temporal resolution is high?
Frame rate is low
High line density
Depth of scan area is reduced or shallow
Field of view is increased
Which of the following best describes an instance when temporal resolution is high?
Depth of scan area is increased or deep
Field of view is reduced
Number of focal zones is increased
Frame rate is high
Which of the following best describes an instance when temporal resolution is high?
Number of focal zones is reduced
Field of view is increased
High line density
Frame rate is low
With regard to maximum imaging depth, was will create a frame in less time?
Deeper depth of view
Shallower depth of view
Medium depth of view
None of the above
If imaging depth of view is doubled, the frame rate will be (a)
With regard to pulses per scan line, what will create a frame with fewer pulses?
Single focus
Multi focus
Triple focus
Quadruple focus
With regard to sector size, what will create a frame with fewer pulses?
Similar sector angle
Varying sector angle
90 degree sector angle
30 degree sector angle
Narrower sector = (a)
Wide sector = (a)
With regard to line density, what will create a frame with fewer pulses?
High line density
Low line density
4 line density
Medium line density
(a) line density images use fewer pulses and have better temporal resolution, but degrades spatial resolution
(a) density in a sector image is the number of scan lines per degree of sector
High frame rate
(a)
Shallower depth
(a)
Fewer pulsed per image
(a)
Single focus, narrow sector, low line density
(a)
Better movie clip: but lower quality image
(a)
Low frame rate, deep depth
(a)
More pulses per image
(a)
Multi focus, wide sector, high line density
(a)
Poor quality video clip: but higher quality image
(a)
Imaging depth and frame rate are (a) related
Assume that an ultrasound system creates each image with 100 distinct sound pulses. Each pulse travels a maximum depth that requires a PRP of 1/1000 second. What is the time needed to make a single frame?
100 Hz
10 Hz
1 Hz
1000 Hz
The pulses time of flight is 0.5/1000 sec, if the image still requires 100 pulses, the time to make a frame is now:
20Hz
200 Hz
2000 Hz
2 Hz
How does the number of pulses in each image affect temporal resolution?
Higher frame rate is possible when each image is made with fewer pulses
Higher frame rate is possible when each image is made with more pulses
Higher frame rate is possible when each image is made with equal pulses
None of these
Pulses per frame and frame rate are (a) related
What factors affect the number of pulses needed to create an image?
Number of pulses per scan line (Focus)
Line density
Period
Sector size
One pulse per scan line
Short T frame
Higher frame rate
Better temporal resolution
Poorer lateral resolution
(a)
Many pulses per scan line
Longer T frame
Lower frame rate
Diminished temporal resolution
Improved lateral resolution
(a)
What is the main advantage of multiple focal zones?
Poorer temporal resolution
Improved temporal resolution
Poorer lateral resolution
Improved lateral resolution
Fewer pulses per frame
Shorter T frame
Higher frame rate
Superior temporal resolution
(a)
More pulses per frame
Longer T frame
Lower frame rate
Inferior temporal resolution
(a)
With sector will have better temporal resolution? (30 or 90)
30
90
Assume that a system creates a 90 degree sector image with a line every 2 degrees, in this case the image comprises of how many distinct pulses?
30
45
60
90
widely spaced lines
fewer pulses per frame
shorter t frame
higher frame rate
high temporal resolution
poor spatial resolution
(a)
tightly packed lines
more pulses per frame
longer t frame
lower frame rate
low temporal resolution
excellent spatial resolution
(a)
Lateral resolution improves with (a)
Spatial resolution improves with (a)
Which of the following forms of resolution improve when frame rate increases?
Lateral
Longitudinal
Temporal
Spatial
Which of the following is consistent with improved temporal resolution?
color doppler
more gray shades
more detail
higher frame rate
All of the following decrease temporal resolution EXCEPT:
lower frame rate
deeper imaging
multi focus
narrower sector
A sonographer adjusts an ultrasound scan to double the depth of view from 5cm to 10cm. What happens to the frame rate?
It is halved
It doubles
It increases from 5 to 10 MHz
It is unchanged
A sonographer adjusts an ultrasound scan to double the depth of view from 5cm to 10cm. if the frame rate remains the same, which of the following also occurs?
Increased line density
Wider sector
Multi focus imaging turned on
Narrower sector
A sonographer adjusts an ultrasound machine to change the sector size from 90 to 45 degrees. Nothing else changes. What happens to the frame rate?
it is doubled
It remains unchanged
It is Halved
it is tripled
A sonographer adjusts an ultrasound system to change the sector from 90 to 45 degrees. The frame rate was unchanged. What else must happen?
Temporal resolution was doubled
Sector size was doubled
Line density was doubled
Imaging depth was doubled
A sonographer, using a phased array ultrasound system, turns off multi focus feature. What is the most likely consequence of this action?
Frame rate decreases
Temporal resolution degrades
Imaging depth increases
Temporal resolution improves
A sonographer increases the line density from 1 per degree of sector to 3 lines per degree of sector. What I the most likely consequence of this action?
Frame rate increases
Temporal resolution decreases
Imaging quality decreases
Temporal resolution increases
A sonographer reduces the sector angle from 90 degrees to 30 degrees. At the same time, the ultrasound system automatically increases the line per degree from 1 to 2 lines per degree. No other changes are made. What will happen to the frame rate?
Increases
Decreases
Remains unchanged
A sonographer reduces the sector angle from 90 degrees to 30 degrees. At the same time, the ultrasound system automatically increases line density from 1 to 3 lines per degree. No other changes are made. What will happen to the temporal resolution?
Increases
Decreases
Remains unchanged
Which of the following is the most important in determining the frame rate of a system?
Depth of view
Dynamic range
Transducer frequency
Transmitter output
What is the frame rate if each image of the ultrasound system is created in 0.02 sec (1/50 sec)
20 Hz
100 Hz
50 Hz
15 Hz
What is the time needed to make a single image if the frame rate of an ultrasound is 20 Hz?
1s
0.02 s
0.05 s
15 Hz
True or false: the critical factor in determining frame rate, line density, and imaging depth is the transducer style
true
false
True or false: the number of lines per frame and the frame rate determine the frequency
True
False
True or false: the number of lines per frame and the frame rate determine the PRF
True
False
True or false: if the imaging depth of a scan is 15cm and there is 100 lines in the image, then the number of pulses making up the scan is 1500
true
false
True or false: if the imaging depth of a scan is 15cm and there are 100 lines in the image, then the number of pulses making up the scan is 100
True
False
When the frame rate is 30 Hz. How long does it take to create a frame?
30 s
3s
0.3s
1/30 s
Under certain conditions, an ultrasound system creates an image in 0.01 seconds. What is the frame rate?
1 Hz
10 sec
100 Hz
0.02 Hz
What is the fundamental limitation of temporal resolution?
Imaging depth
Speed of sound in the medium
Line density
sector size
