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True or False. Mechanical scanning produces pictures that are similar in shape to linear phased array images.
True
3 multiple choice options
True or False. Many active elements fire at almost the same time in a mechanical scanner.
False
3 multiple choice options
True or False. Many active elements fire at almost the same time in a phased array scanner.
True
3 multiple choice options
Which of the following transducers is best described as mechanically steered and fixed, single focused?
mechanical
3 multiple choice options
Which of the following is best described as mechanically steered and multi-focus?
annular phased array transducer
3 multiple choice options
Which of the following forms of resolution improves when frame rate increases?
temporal
3 multiple choice options
Which of the following is consistent with improved temporal resolution?
higher frame rate
3 multiple choice options
All of the following decrease temporal resolution except.
narrower sector
3 multiple choice options
A sonographer adjusts an ultrasound scan to double the depth of view from 5 cm to 10 cm. What happens to the frame rate?
it is halved
3 multiple choice options
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?
narrower sector
3 multiple choice options
A sonographer, using a phased array ultrasound system, turns off the multi-focus feature. What is the most likely consequence of this action?
temporal resolution improves
3 multiple choice options
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?
temporal resolution decreases
3 multiple choice options
Which of the following is most important in determining the frame rate of a system?
speed of sound in the medium
3 multiple choice options
Which of the following is most important in determining the frame rate for a system?
depth of view
3 multiple choice options
What is the frame rate if each image of the ultrasound system is created in 0.02 sec (1/50 sec)?
50 Hz
3 multiple choice options
Two digital scan converters are undergoing evaluation. System A has 1,000,000 pixels and the picture size is 100 square inches. System B has an image size of 10 square inches composed of 250,000 pixels. Which image is more likely to display very small details?
system b
3 multiple choice options
Two digital scan converters are undergoing evaluation. Both produce images of the same size. System A has 1,000,000 pixels, with 10 bits assigned to each. System B has 250,000 pixels, with 12 bits assigned to each. Which system is more likely to have the capability of displaying very small details in an image?
system A
3 multiple choice options
True or False? Postprocessing of image data occurs after the data has been stored in the scan converter.
true
3 multiple choice options
True or False? Preprocessing of image data occurs after the data has been stored in the scan converter.
false
3 multiple choice options
True or False? The greater the number of bits assigned to each pixel of digital image, the greater the number of shades of gray in the image is.
True
3 multiple choice options
True or False? The greater the number of bits assigned to each pixel of a digital image, the greater the spatial resolution of the image is.
False
3 multiple choice options
What is the smallest amount of digital storage called?
bit
3 multiple choice options
True or False? Both digital and analog scan converters use computer technology to process electronic data into images.
False
3 multiple choice options
Analog scale converters have all of the following limitations except:
low spatial resolution
3 multiple choice options
What is the smallest part of a digital picture called?
pixel
3 multiple choice options
True or False? A digital representation of a number can achieve only specific fixed values.
true
3 multiple choice options
Which of the following is best described as an analog number?
the weight of a person
3 multiple choice options
All of the following are advantages of PACS systems except.
images have higher resolution than what appears on the system's display
3 multiple choice options
What is the primary disadvantage of video tape and computer disc methods of image archiving?
the information is vulnerable to erasure when exposed to strong magnetic fields
3 multiple choice options
All of the following are characteristics of write magnification except.
identical regions stored in the scan converter before and after zooming
3 multiple choice options
True or False? All artifacts are errors in imaging that do not represent the true anatomy of the imaged organ. Therefore, they are all undesirable and should be eliminated if possible
False
3 multiple choice options
What is the most likely cause of ring down artifact?
Reflection
3 multiple choice options
While imaging a test object, an ultrasound system displays one image 1.8 cm deeper than another. Upon measuring the test object, it is found that it is actually 2.0 cm deeper. What conclusion can be drawn from this?
speed in soft tissue is less than that of the test object
3 multiple choice options
Acoustic focusing of an ultrasound beam may create which artifact?
Enhancement
3 multiple choice options
When enhancement occurs, where does it appear on the image?
deeper than a weak attenuator
3 multiple choice options
Unexpectedly low attenuation results in which of the artifacts listed below?
enhancement
3 multiple choice options
Which of these produces shadowing?
attenuation
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How is shadowing artifact expressed?
reflectors being absent on the image
3 multiple choice options
Where are shadowing artifacts commonly seen on an acoustic scan?
deeper than a structure with a high attenuation
3 multiple choice options
What causes enhancement artifact?
unexpectedly low acoustic attenuation
3 multiple choice options
What is a comet tail artifact's fundamental mechanism of formation?
reflection
3 multiple choice options
What are the characteristics of a medium that produces comet tail artifact?
strong reflectors, closely spaced, high propagation speed
3 multiple choice options
Where is a mirror image artifact located?
always deeper on the image than in the body
3 multiple choice options
Which process causes mirror image artifact?
reflection
3 multiple choice options
Which situation will commonly produce reverberation artifact?
two strong reflectors that lie along the main axis of the beam
3 multiple choice options
Two otherwise identical Doppler studies are performed, except that the angle between flow and the sound beam is 0 degrees in the first study and 60 degrees in the second. The velocity measured in the first study is 2 m/s. What velocity will be measured in the second study?
1 m/s
3 multiple choice options
When using a 4 MHz transducer, a Doppler shift of 3,000 Hz is recorded), what will the Doppler shift be when a 2 MHz transducer is used?
1,500 Hz
3 multiple choice options
Blood moving at a velocity of 2 m/s creates a Doppler frequency of 3,000 Hz. What will the Doppler shift be if the velocity increases to 4 m/s?
6,000 Hz
3 multiple choice options
Two ultrasound transducers are used to perform Doppler exams on the same patient. The exams are identical except that the transducer frequencies are 5 and 2.5 MHz. Which exam will measure the highest velocities?
neither
3 multiple choice options
The arterial blood pressure of a standing individual is 120 mmHg. What is the hydrostatic pressure at the subject's ankle?
100 mmHg
3 multiple choice options
The arterial blood pressure of a supine individual is 120 mmHg. What is the hydrostatic pressure at the subject's hips?
0 mmHg
3 multiple choice options
The arterial blood pressure of a supine individual is 120 mmHg. What is the hydrostatic pressure at the subject's ankle?
0 mmHg
3 multiple choice options
Which of the following causes the greatest amount of inertial energy loss?
flow through a stenosis
3 multiple choice options
All of the following decrease the flow energy of a fluid except:
frictional loss
viscous loss
velocity loss
inertial loss
velocity loss
3 multiple choice options
What is the primary reason why blood moves from one location to another?
energy gradient
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Which of the following is not associated with turbulent flow?
swirling
parabolic
eddy
vortex
parabolic
3 multiple choice options
Which of the following terms does not belong with the others?
phasic
spontaneous
pulsatile
venous
pulsatile
3 multiple choice options
Which of the following flow patterns is associated with cardiac contraction?
pulsatile
3 multiple choice options
True or False? On a color Doppler image, red always represents flow toward the transducer, whereas blue indicates flow away from the transducer.
false
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Which of the following is NOT associated with laminar flow?
layered
normal
aligned
smooth
chaotic
chaotic
3 multiple choice options
True or False? The appearance of negative velocities in a pulsed Doppler display always indicates that red blood cells are moving away from the transducer.
False
3 multiple choice options
