Chapter 13 Flashcards
Which of the following forms of resolution improve when frame rate increases? Lateral Longitudinal Temporal Spatial resolution
Temporal
Which of the following is consistent with improved temporal resolution? Color doppler More gray shades More detail Higher frame rate
Higher frame rate
All of the following decrease temporal resolution except: Lower frame rate Deeper imaging Multi-focus Narrower sector
Narrower sector
A sonographer adjusts an ultrasound scan to double to double the depth of view from 5 cm to 10 cm. What happens to the frame rate?
It is halved
A sonographer adjusts an ultrasound scan to double the depth of view from 5 cm to 10 cm. If the frame rate remains the same, which one of the following also occurs?
Narrow 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
A sonographer adjusts an ultrasound machine to change the sector size from 90 to 45 degrees. The frame rate was unchanged. What else must have happened?
Line density was doubled
A sonographer, using a phased array ultrasound system, turns off the multi-focus feature. What is the most likely consequence of this action? Frame rate decreases Temporal resolution degrades Imaging depth increases Temporal resolution improved
Temporal resolution improves
A sonographer increases the line density from 1 line per degree of sector to 3 lines per degree of sector. What is the most likely consequence of this action? Frame rate increases Temporal resolution decreases Imaging quality decreases Temporal resolution increases
Temporal resolution decreases
A sonographer reduces the sector angle from 90 degrees to 30 degrees. At the same time, the ultrasound system automatically increases the line density from 1 line per degree to 2 lines per degree. No other changes are made. What will happen to the frame rate?
Increases
A sonographer reduces the sector angle from 90 degrees to 30 degrees. At the same time, the ultrasound system automatically increases the line density from 1 line per degree to 3 lines per degree. No other changes are made. What will happen to the temporal resolution?
Remains unchanged
Which of the following is most important in determining the frame rate of a system? Speed of sound in the medium Dynamic range of the receiver Transducer frequency Transmitter output
Speed of sound in the medium
Which of the following is most important in determining the frame rate of a system? Depth of view Dynamic range of the receiver Transducer frequency Transmitter output
Depth of view
What is the frame rate if each image of the ultrasound system is created in 0.02 sec (1/50 sec)?
50 Hz
What is the time needed to make a single image if the frame rate of an ultrasound system is 20 Hz?
0.05 s
T or F. The critical factor in determining frame rate, line density, and imaging depth is the transducer style.
False
T or F. The number of liner per frame and the frame rate determine the frequency.
False
T or F. The number of liner per frame and the frame rate determine the PRF?
True
T or F. If the imaging depth of a scan is 15 cm and there are 100 lines in the image, then the number of pulses making up the scan is 1500.
false
T or F. If the imaging depth of a scan is 15 cm and there are 100 lines in the image, then the number of pulses making up the scan is 100.
True
T or F. If 100 scan lines make up an image and the frame rate is 30 per second, then the transducer’s frequency is 3,000 Hz.
False
T or F. If 100scan lines make up an image and the frame rate is 30 per second, then the system’s pulse repetition frequency is 3,000 Hz.
True
When the frame rate is 30 Hz, how long does it take to create a frame?
1/3 seconds
Under certain conditions, an ultrasound creates each image in 0.01 seconds. What is the frame rate?
200 Hz
What is the fundamental limitation of temporal resolution?
Speed of sound in the medium
