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WorksheetsChapter 21 2/3
Total questions: 65
Worksheet time: 33mins
What is a misconception sonographers may have about the 2-D imaging plane?
It is thick and variable
It is always 3-D
It is thin and uniform, like a slice of cheese
It is bell-shaped like a trumpet
What is the actual shape and dimension of the imaging plane?
Flat and uniform
Three-dimensional and non-uniform
Cylindrical and constant
Two-dimensional and thin
What causes slice thickness artifact in ultrasound imaging?
Reflections from structures above or below the assumed imaging plane
Poor axial resolution
Shadowing from bone
Misalignment of the transducer
What does the ultrasound beam resemble in shape as it extends from the transducer?
A bell of a trumpet
A pencil
A laser beam
A thin wire
What aspect of resolution is determined by the thickness of the imaging plane?
Lateral resolution
Axial resolution
Temporal resolution
Elevation resolution
When does slice thickness artifact typically appear?
When the beam dimension is greater than the reflector size
When the beam is focused
Only during Doppler imaging
At shallow depths only
What is another name for slice thickness artifact?
Axial resolution artifact
Lateral resolution artifact
Section thickness artifact
Time gain artifact
What is a key characteristic of the imaging plane in slice thickness artifact?
It is always the same thickness
It is thicker at the edges
The thickness varies
It is thinnest at the center
Thicker portions of the imaging slice have:
Inferior elevation resolution
Superior lateral resolution
No impact on resolution
Improved image contrast
What does slice thickness artifact typically result in on an ultrasound image?
A clearer visualization of solid organs
Filling in of hollow structures such as cysts
Increased acoustic shadowing
Reverberation echoes
Where is the true reflector located in the case of slice thickness artifact?
Directly in the imaging plane
Above or below the assumed imaging plane
Next to the imaging plane laterally
In the focal zone of the transducer
Which type of transducer helps reduce slice thickness artifact?
Mechanical sector transducer
Linear array transducer
1.5-dimensional array transducer
Continuous wave Doppler probe
Which invalid assumption is associated with slice thickness artifact?
Sound travels at exactly 1,540 m/s
The imaging plane is extremely thin
Sound travels in a straight line
Echoes originate only from structures in the beam's main axis
What is another name for lateral resolution artifact?
Reverberation artifact
Mirror artifact
Comet tail artifact
Point spread artifact
When does lateral resolution artifact occur?
When a beam is narrower than the distance between two reflectors
When a beam is wider than the distance between two reflectors that are side to side
When two reflectors are positioned in a vertical line
When the transducer angle is too steep
How does lateral resolution artifact affect the appearance of two reflectors?
They appear brighter than they are
They appear as one object
They appear at different depths
They appear with higher contrast
How does lateral resolution artifact affect the display of a small reflector?
It appears deeper than it actually is
It appears as a wide line
It appears twice
It disappears from the image
What can improve lateral resolution?
Increased gain
Lower frequency
Focusing
Larger beam width
What causes axial resolution artifact in ultrasound imaging?
When a wide beam strikes two side-by-side structures
When a long pulse strikes two closely spaced structures, one in front of the other
When Doppler shift is incorrectly calculated
When the transducer fails to emit pulses
Under what condition will only one reflector appear on the image in axial resolution artifact?
When structures are farther apart than one spatial pulse length
When structures are closer together than the beam width
When structures are closer together than one-half spatial pulse length
When structures are moving rapidly
Which type of transducer provides better axial resolution?
Lower frequency transducers
Higher frequency transducers
Broadband transducers
Phased array transducers
What causes multipath artifacts in ultrasound imaging?
Sound pulses traveling in a perfectly straight line
Sound pulses glancing off a second structure on the way to or from the primary reflector
Sound pulses bouncing off the skin surface only
Echoes generated from the transducer cable
What is the result of a multipath artifact in ultrasound imaging?
Complete absence of the primary reflector
Subtle, nonspecific changes in the image
An obvious bright spot on the image
A perfectly symmetrical image artifact
Which assumption is violated by multipath artifacts?
That all echoes return at the same speed
That a pulse travels directly to a structure and back
That the transducer is always perpendicular
That reflectors always appear brighter than they are
What happens when a sound beam strikes a curved or oblique reflector?
Some of the sound may be directed away from the transducer
The sound is always reflected back fully
The reflector becomes enhanced on the image
The reflector completely disappears from view
How do curved and oblique reflectors typically appear on an ultrasound image?
Absent, weak, or different from similar reflectors
Stronger and brighter than expected
Unchanged in any way
What does temporal resolution in ultrasound refer to?
Ability to measure blood velocity
Ability to precisely position a moving structure
Ability to enhance image contrast
Ability to determine tissue density
What determines temporal resolution in ultrasound imaging?
Transducer frequency
Image depth
Frame rate
Gain settings
What happens when temporal resolution is poor due to low frame rates?
Less accurate positioning of reflectors in motion
Increased image brightness
Better image resolution
Improved Doppler measurements
What is spatial resolution in ultrasound imaging related to?
Depth of the image
Size of the transducer
Overall detail in an image
Speed of sound in tissue
What determines the spatial resolution of an ultrasound image?
Type of tissue being scanned
Sound beam’s spacing or line density
Frequency of the probe
Time gain compensation settings
Which of the following provides superior spatial resolution?
Higher line density (closely packed pulses)
Lower line density (widely spaced pulses)
Longer pulse duration
Wider beam width
Lower line density on an image indicates:
Less detail and inferior spatial resolution
More contrast and better resolution
Higher frequency and improved penetration
Increased signal-to-noise ratio
What is spatial resolution in a digital display related to?
Frame rate
Pixel density
Beam width
Transducer frequency
How does a high pixel density affect spatial resolution?
Decreases spatial resolution
Has no effect on image detail
Improves spatial resolution by providing more detail
Increases the size of each pixel
What happens when pixel size is greater than the size of the reflector?
A spatial resolution artifact occurs
Image quality improves
The image becomes brighter
Temporal resolution improves
What is a characteristic of low pixel density in a digital display?
Each pixel is large
Image detail increases
Each pixel is small
Improves spatial resolution
What causes the Range Ambiguity Artifact in ultrasound imaging?
All reflections are received before the next pulse is transmitted
Reflections from shallow structures arriving late
Reflections from deep structures received after the next pulse is transmitted
Increased frequency of the transmitted pulse
How does the Range Ambiguity Artifact appear on an ultrasound image?
As a duplicate reflector at the correct depth
As a reflector appearing deeper than its actual location
As a reflector appearing shallower than its actual location
As a highly echogenic mass
What adjustment can eliminate the Range Ambiguity Artifact?
Increasing the PRF
Increasing the frequency
Increasing the PRP
Decreasing the gain
Why does increasing the PRP help in eliminating range ambiguity?
It decreases the resolution of the image
It reduces the number of transmitted pulses
It allows more time for deep reflections to return before the next pulse
It enhances the axial resolution
What is noise in ultrasound imaging?
High amplitude echoes from bone
Artifacts caused by mirror reflectors
Small amplitude echoes from various sources
An enhancement artifact from fluid
Which of the following is NOT a typical source of noise in ultrasound imaging?
Tissue harmonic generation
Electrical interference
Signal processing
Spurious reflections
In ultrasound, noise is more likely to affect which type of region?
Low-level hypoechoic regions
Bright echogenic areas
Highly vascular regions
Bone surfaces
Which of the following is considered a form of noise in ultrasound imaging?
Speckle
Gain
Axial resolution
Lobe artifact
What type of artifact is referred to as clutter in ultrasound imaging?
An enhancement artifact
A type of reverberation
A form of noise
A reflection from deep tissue
What is speckle artifact in ultrasound imaging?
A reflection of deep tissue structures
A motion artifact from patient movement
Noise from interference of sound wavelets
A defect caused by equipment malfunction
Which of the following best describes the appearance of speckle artifact?
Bright horizontal lines in the image
Grainy tissue-like texture not related to actual anatomy
Dark shadowing behind structures
Mirror image duplication of vessels
What causes speckle artifact?
Only destructive interference of sound waves
Artifacts from bone reflection
Constructive and destructive interference of small wavelets
Reverberation echoes only
Which of the following can help reduce speckle artifact?
Increased transducer pressure
Spatial compounding
Using a lower frequency transducer
Reducing frame rate
In which region of the ultrasound image is speckle most commonly observed?
Shallow regions
Deep abdominal organs
Pelvic region
Near bones only
What is clutter in ultrasound imaging?
A type of aliasing artifact
The presence of false echo signals from outside the main sound beam
An artifact caused by low-frequency sound waves
A form of attenuation error
Which of the following are sources of clutter?
Color Doppler and pulse inversion
Side lobes, grating lobes, and thickness artifacts
High-frequency attenuation and reverberation
Refraction and acoustic shadowing
How does clutter affect Doppler imaging?
It causes color flash artifacts
It contaminates valid Doppler signals with high amplitude reflections
It increases spectral resolution
It reduces the overall power output of the transducer
What causes high amplitude reflections in Doppler that lead to clutter?
Only moving blood cells
Vessel walls or heart muscle
Attenuation layers in tissue
Temperature variations in the medium
What is one of the primary benefits of using harmonic imaging in ultrasound?
It increases the speed of the ultrasound waves.
It decreases the resolution of the image.
It reduces the image’s noise content.
It eliminates the need for Doppler imaging.
What is the goal of harmonic imaging?
To create multiple reflections from one sound wave.
To selectively distinguish meaningful reflections from noise.
To improve the color Doppler effect.
To reduce the frame rate of imaging.
What is the outcome of using harmonic imaging in terms of signal clarity?
Reduced image clarity.
Increased signal-to-noise ratio.
Increased noise-to-signal ratio.
Lower dynamic range.
Which of the following can cause anatomic reflectors to be absent on an ultrasound image?
Enhancement
Shadowing
Speed errors
Multipath
Which artifact causes an anatomic reflector to appear multiple times on the image, positioned deeper than the true anatomy?
Refraction
Comet tail
Slice thickness
Speed error
Which artifact causes reflectors to appear multiple times, displaced to the side of the true anatomy?
Mirror image
Comet tail
Side lobe
Acoustic speckle
Which artifact can cause anatomic reflectors to appear with abnormal brightness?
Refraction
Shadowing
Acoustic speckle
Speed errors
Which artifacts cause anatomic structures to appear at incorrect depths?
Refraction and shadowing
Speed errors and range ambiguity
Side lobe and grating lobe
Slice thickness and speckle
Which artifact causes anatomic structures to appear in the incorrect imaging plane?
Refraction
Slice thickness
Grating lobe
Comet tail
Which artifacts result in anatomic structures that do not correspond to echoes on the image?
Acoustic speckle and multipath
Mirror image and shadowing
Range ambiguity and side lobe
