Question #1
What causes color flash artifact?
- A . Aliasing
- B . Tissue motion
- C . High velocity blood flow
- D . Strong reflector
Correct Answer: B
B
Explanation:
Color flash artifact occurs due to tissue motion. This artifact is a type of color Doppler artifact that happens when there is movement of tissue or transducer, which causes the Doppler system to incorrectly interpret the motion as blood flow. This results in a flash of color appearing on the image where there is actually no flow. Tissue motion affects the Doppler signal, leading to misinterpretation by the system, and hence the artifact appears as a flash of color.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
B
Explanation:
Color flash artifact occurs due to tissue motion. This artifact is a type of color Doppler artifact that happens when there is movement of tissue or transducer, which causes the Doppler system to incorrectly interpret the motion as blood flow. This results in a flash of color appearing on the image where there is actually no flow. Tissue motion affects the Doppler signal, leading to misinterpretation by the system, and hence the artifact appears as a flash of color.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
Question #2
Which statement describes the purpose of using a spectral Doppler wall filter?
- A . To widen the area in which the Doppler shift is sampled
- B . To clean up the audio signals
- C . To eliminate the higher velocity signals
- D . To eliminate the lower velocity signals
Correct Answer: D
D
Explanation:
The purpose of using a spectral Doppler wall filter is to eliminate lower velocity signals. Wall filters are designed to remove low-frequency Doppler shifts caused by the motion of the vessel walls or surrounding tissues, which are generally of no diagnostic value. By eliminating these lower velocity signals, the wall filter helps to clean up the Doppler signal and reduce clutter, allowing for a clearer and more accurate display of blood flow velocities.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
D
Explanation:
The purpose of using a spectral Doppler wall filter is to eliminate lower velocity signals. Wall filters are designed to remove low-frequency Doppler shifts caused by the motion of the vessel walls or surrounding tissues, which are generally of no diagnostic value. By eliminating these lower velocity signals, the wall filter helps to clean up the Doppler signal and reduce clutter, allowing for a clearer and more accurate display of blood flow velocities.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
Question #3
Which artifact may be caused by incorrect color Dopplergain setting?
- A . Bleed/Blossoming
- B . Clutter/Haze
- C . Twinkle
- D . Aliasing
Correct Answer: A
A
Explanation:
Incorrect color Doppler gain settings can cause the artifact known as bleed or blossoming. When the color Doppler gain is set too high, it can cause the color signal to "bleed" outside the actual boundaries of the blood vessel, leading to an overestimation of the area of flow. This artifact makes it appear as though the blood flow extends beyond the true vessel walls, which can obscure the accurate interpretation of the Doppler image.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
A
Explanation:
Incorrect color Doppler gain settings can cause the artifact known as bleed or blossoming. When the color Doppler gain is set too high, it can cause the color signal to "bleed" outside the actual boundaries of the blood vessel, leading to an overestimation of the area of flow. This artifact makes it appear as though the blood flow extends beyond the true vessel walls, which can obscure the accurate interpretation of the Doppler image.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
Question #4
Which target group is used to evaluate transverse distance measurement accuracy in this tissue-mimicking phantom image?
- A . Option A
- B . Option B
- C . Option C
- D . Option D
Correct Answer: D
D
Explanation:
In the tissue-mimicking phantom image, Option D (blue box) is used to evaluate transverse distance measurement accuracy. Phantoms are used to simulate human tissue and provide a standardized way to test the accuracy and precision of ultrasound machines. Transverse distance measurement accuracy is assessed by measuring known distances between targets in the phantom. The blue box (Option D) typically contains targets positioned to specifically test the accuracy of transverse measurements, ensuring that the ultrasound system provides reliable and precise distance readings.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Quality Assurance for Ultrasound Imaging Systems" by AAPM (American Association of Physicists in Medicine)
D
Explanation:
In the tissue-mimicking phantom image, Option D (blue box) is used to evaluate transverse distance measurement accuracy. Phantoms are used to simulate human tissue and provide a standardized way to test the accuracy and precision of ultrasound machines. Transverse distance measurement accuracy is assessed by measuring known distances between targets in the phantom. The blue box (Option D) typically contains targets positioned to specifically test the accuracy of transverse measurements, ensuring that the ultrasound system provides reliable and precise distance readings.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Quality Assurance for Ultrasound Imaging Systems" by AAPM (American Association of Physicists in Medicine)
Question #5
Which adjustment will reduce the artifact in the cystic lesion in image A resulting in image B?
- A . Turn off harmonics
- B . Increase dynamic range
- C . Turn on edge enhancement
Correct Answer: C
C
Explanation:
Edge enhancement is a processing technique used in ultrasound imaging to improve the visibility of the edges of structures.
In image A, the borders of the cystic lesion might appear less defined due to a lack of edge enhancement.
By turning on edge enhancement, the ultrasound system processes the image to accentuate the boundaries, leading to a clearer and more distinct outline of the cystic lesion as seen in image B. This adjustment reduces the artifact within the cystic lesion by emphasizing the differences in the adjacent tissue interfaces, thus improving the overall image quality.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines on image optimization techniques.
C
Explanation:
Edge enhancement is a processing technique used in ultrasound imaging to improve the visibility of the edges of structures.
In image A, the borders of the cystic lesion might appear less defined due to a lack of edge enhancement.
By turning on edge enhancement, the ultrasound system processes the image to accentuate the boundaries, leading to a clearer and more distinct outline of the cystic lesion as seen in image B. This adjustment reduces the artifact within the cystic lesion by emphasizing the differences in the adjacent tissue interfaces, thus improving the overall image quality.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines on image optimization techniques.
Question #6
What is the primary reason to use compression?
- A . Increase line density
- B . Reduce the focal region
- C . Improve the axial resolution
- D . Adjust the contrast resolution
Correct Answer: D
D
Explanation:
Compression in ultrasound imaging adjusts the range of grayscale displayed, affecting the contrast resolution.
This function allows sonographers to enhance the differentiation between structures of varying echogenicities.
By modifying the contrast resolution, sonographers can better visualize subtle differences in tissue composition and improve the diagnostic quality of the images.
Increasing contrast resolution is particularly important in differentiating between fluid-filled cysts and solid masses.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on image processing and contrast resolution.
D
Explanation:
Compression in ultrasound imaging adjusts the range of grayscale displayed, affecting the contrast resolution.
This function allows sonographers to enhance the differentiation between structures of varying echogenicities.
By modifying the contrast resolution, sonographers can better visualize subtle differences in tissue composition and improve the diagnostic quality of the images.
Increasing contrast resolution is particularly important in differentiating between fluid-filled cysts and solid masses.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on image processing and contrast resolution.
Question #7
Which resolution capability is most affected by spatial pulse length?
- A . Elevational
- B . Temporal
- C . Lateral
- D . Axial
Correct Answer: D
D
Explanation:
Axial resolution refers to the ability to distinguish two structures that are close to each other along the path of the ultrasound beam.
Spatial pulse length (SPL) is the distance over which one pulse occurs, and it directly affects axial resolution.
Shorter SPL improves axial resolution because it allows better differentiation of closely spaced structures.
The axial resolution is improved by increasing the frequency of the transducer, which shortens the wavelength and hence the SPL.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on resolution parameters and their impact on image quality.
D
Explanation:
Axial resolution refers to the ability to distinguish two structures that are close to each other along the path of the ultrasound beam.
Spatial pulse length (SPL) is the distance over which one pulse occurs, and it directly affects axial resolution.
Shorter SPL improves axial resolution because it allows better differentiation of closely spaced structures.
The axial resolution is improved by increasing the frequency of the transducer, which shortens the wavelength and hence the SPL.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on resolution parameters and their impact on image quality.
Question #8
What is the function of M-mode?
- A . Create 3D images
- B . Visualize internal organs
- C . Monitor blood flow
- D . Measure movement
Correct Answer: D
D
Explanation:
M-mode (Motion mode) is used in ultrasound to measure and display the movement of structures over time.
This mode is particularly useful in cardiac imaging to assess the motion of heart walls and valves. M-mode provides a one-dimensional view of the motion of tissues and is often used in conjunction with 2D imaging for a comprehensive assessment.
It is essential in evaluating the dynamic function of organs, especially in cardiology, where precise measurements of cardiac structures’ movement are crucial.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on modes of ultrasound imaging and their clinical applications.
D
Explanation:
M-mode (Motion mode) is used in ultrasound to measure and display the movement of structures over time.
This mode is particularly useful in cardiac imaging to assess the motion of heart walls and valves. M-mode provides a one-dimensional view of the motion of tissues and is often used in conjunction with 2D imaging for a comprehensive assessment.
It is essential in evaluating the dynamic function of organs, especially in cardiology, where precise measurements of cardiac structures’ movement are crucial.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on modes of ultrasound imaging and their clinical applications.
Question #9
Which factor has a positive effect on temporal resolution?
- A . Increase in scan depth
- B . Use of spatial compounding
- C . Increase in number of focal zones
- D . Use of narrow sector width
Correct Answer: D
D
Explanation:
Temporal resolution refers to the ability to accurately depict moving structures over time.
A narrow sector width reduces the area being scanned, which increases the frame rate because fewer scan lines are required per frame.
Higher frame rates improve temporal resolution, allowing for better visualization of fast-moving structures.
Other factors like scan depth and the number of focal zones also affect frame rate but typically reduce it when increased, thereby decreasing temporal resolution.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on factors affecting temporal resolution and frame rate.
D
Explanation:
Temporal resolution refers to the ability to accurately depict moving structures over time.
A narrow sector width reduces the area being scanned, which increases the frame rate because fewer scan lines are required per frame.
Higher frame rates improve temporal resolution, allowing for better visualization of fast-moving structures.
Other factors like scan depth and the number of focal zones also affect frame rate but typically reduce it when increased, thereby decreasing temporal resolution.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on factors affecting temporal resolution and frame rate.
Question #10
Which factor affects temporal resolution?
- A . Display depth
- B . Time gain compensation
- C . Overall gain
- D . Log compression
Correct Answer: A
A
Explanation:
Temporal resolution refers to the ability of an ultrasound system to distinguish between events occurring closely in time. It is primarily affected by the frame rate, which is the number of frames displayed per second. One of the main factors that influence the frame rate is the display depth. The deeper the imaging depth, the longer it takes for the ultrasound pulses to travel to the target and back, thus reducing the frame rate and temporal resolution. Shallower imaging depths allow for higher frame rates and better temporal resolution.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
A
Explanation:
Temporal resolution refers to the ability of an ultrasound system to distinguish between events occurring closely in time. It is primarily affected by the frame rate, which is the number of frames displayed per second. One of the main factors that influence the frame rate is the display depth. The deeper the imaging depth, the longer it takes for the ultrasound pulses to travel to the target and back, thus reducing the frame rate and temporal resolution. Shallower imaging depths allow for higher frame rates and better temporal resolution.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
Question #11
Which type of structure is best visualized with low persistence?
- A . Anechoic
- B . Static
- C . Echogenic
- D . Dynamic
Correct Answer: D
D
Explanation:
Low persistence is best used for visualizing dynamic structures. Persistence is a setting that controls the averaging of successive frames to reduce noise and improve image quality. While high persistence can be beneficial for imaging static structures by providing a smoother image, it can blur or smear moving structures, making it difficult to visualize motion accurately. Low persistence settings allow for better temporal resolution and are therefore ideal for observing dynamic or moving structures such as the heart or blood flow.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
D
Explanation:
Low persistence is best used for visualizing dynamic structures. Persistence is a setting that controls the averaging of successive frames to reduce noise and improve image quality. While high persistence can be beneficial for imaging static structures by providing a smoother image, it can blur or smear moving structures, making it difficult to visualize motion accurately. Low persistence settings allow for better temporal resolution and are therefore ideal for observing dynamic or moving structures such as the heart or blood flow.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
Question #12
What is the relationship between overall gain and image brightness?
- A . The higher the overall gain, the brighter the image
- B . The lower the overall gain, the brighter the image
- C . The higher the overall gain, the darker the image
- D . There is no relationship between overall gain and image brightness
Correct Answer: A
A
Explanation:
Overall gain in ultrasound refers to the amplification of all the received echo signals. Increasing the overall gain amplifies the signals, making the entire image brighter. Conversely, decreasing the overall gain reduces the signal amplification, resulting in a darker image. Overall gain adjustment affects the entire image uniformly, unlike time gain compensation (TGC), which adjusts the gain at different depths independently.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
A
Explanation:
Overall gain in ultrasound refers to the amplification of all the received echo signals. Increasing the overall gain amplifies the signals, making the entire image brighter. Conversely, decreasing the overall gain reduces the signal amplification, resulting in a darker image. Overall gain adjustment affects the entire image uniformly, unlike time gain compensation (TGC), which adjusts the gain at different depths independently.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
Question #13
Which settings will lead to the highest temporal resolution?
- A . 45-degree sector width, 4 cm scan depth, color Doppler off
- B . 60-degree sector width, 5 cm scan depth, color Doppler off
- C . 45-degree sector width, 4 cm scan depth, color Doppler on
- D . 60-degree sector width, 5 cm scan depth, color Doppler on
Correct Answer: A
A
Explanation:
The settings that lead to the highest temporal resolution are those that reduce the amount of information that the ultrasound system needs to process, allowing for a higher frame rate. A smaller sector width and shallower scan depth reduce the area that needs to be imaged, enabling faster data acquisition. Turning off color Doppler further reduces processing demands, as the system no longer needs to compute and display color flow information. Therefore, a 45-degree sector width, 4 cm scan depth, and color Doppler off will provide the highest temporal resolution.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
A
Explanation:
The settings that lead to the highest temporal resolution are those that reduce the amount of information that the ultrasound system needs to process, allowing for a higher frame rate. A smaller sector width and shallower scan depth reduce the area that needs to be imaged, enabling faster data acquisition. Turning off color Doppler further reduces processing demands, as the system no longer needs to compute and display color flow information. Therefore, a 45-degree sector width, 4 cm scan depth, and color Doppler off will provide the highest temporal resolution.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
Question #14
Which parameters determine the propagation speed of sound in a medium?
- A . Frequency and impedance
- B . Amplitude and impedance
- C . Intensity and density
- D . Elasticity and density
Correct Answer: D
D
Explanation:
The propagation speed of sound in a medium is determined by the medium’s elasticity and density. Elasticity refers to the ability of the medium to return to its original shape after deformation, while is the density.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
D
Explanation:
The propagation speed of sound in a medium is determined by the medium’s elasticity and density. Elasticity refers to the ability of the medium to return to its original shape after deformation, while is the density.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide "Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
Question #15
Which target group in this image of a tissue-mimicking phantom is used for gray-scale evaluation?
- A . Option A
- B . Option B
- C . Option C
- D . Option D
Correct Answer: C
C
Explanation:
Gray-scale evaluation in a tissue-mimicking phantom involves assessing the uniformity and accuracy of the gray-scale representation of the tissues.
Option C typically contains structures designed to test the machine’s ability to accurately depict varying levels of echogenicity, which is essential for proper gray-scale evaluation.
This area will have a range of echo intensities that help in determining the contrast resolution and the ability of the system to distinguish between different tissue types based on their gray-scale values.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on tissue-mimicking phantoms and image quality evaluation.
C
Explanation:
Gray-scale evaluation in a tissue-mimicking phantom involves assessing the uniformity and accuracy of the gray-scale representation of the tissues.
Option C typically contains structures designed to test the machine’s ability to accurately depict varying levels of echogenicity, which is essential for proper gray-scale evaluation.
This area will have a range of echo intensities that help in determining the contrast resolution and the ability of the system to distinguish between different tissue types based on their gray-scale values.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on tissue-mimicking phantoms and image quality evaluation.
Question #16
What adjustment is needed to optimize the color in the image below?
- A . Decrease gain
- B . Increase wall filter
- C . Decrease persistence
- D . Increase pulse repetition frequency
Correct Answer: D
D
Explanation:
Increasing the pulse repetition frequency (PRF) helps to optimize the color Doppler imaging by reducing aliasing.
Aliasing occurs when the PRF is too low to accurately sample the rapid blood flow velocities, leading to incorrect color representation.
By increasing the PRF, the system can more accurately measure higher velocities without distortion, improving the overall quality of the color Doppler image.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on Doppler imaging and techniques to reduce aliasing.
D
Explanation:
Increasing the pulse repetition frequency (PRF) helps to optimize the color Doppler imaging by reducing aliasing.
Aliasing occurs when the PRF is too low to accurately sample the rapid blood flow velocities, leading to incorrect color representation.
By increasing the PRF, the system can more accurately measure higher velocities without distortion, improving the overall quality of the color Doppler image.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on Doppler imaging and techniques to reduce aliasing.
Question #17
What is the primary purpose of backing material in transducers?
- A . Improving axial resolution
- B . Increasing the number of cycles in a pulse
- C . Preventing electrical shock to the operator or patient
- D . Improving acoustic impedance matching
Correct Answer: A
A
Explanation:
The backing material, also known as damping material, in an ultrasound transducer serves to dampen the vibrations of the piezoelectric crystal.
This damping reduces the number of cycles in each pulse, leading to a shorter spatial pulse length (SPL).
Shorter SPL improves axial resolution by allowing the system to better distinguish between two closely spaced structures along the axis of the ultrasound beam.
Improved axial resolution is crucial for producing clearer, more detailed images.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on transducer design and the role of backing material in image quality.
A
Explanation:
The backing material, also known as damping material, in an ultrasound transducer serves to dampen the vibrations of the piezoelectric crystal.
This damping reduces the number of cycles in each pulse, leading to a shorter spatial pulse length (SPL).
Shorter SPL improves axial resolution by allowing the system to better distinguish between two closely spaced structures along the axis of the ultrasound beam.
Improved axial resolution is crucial for producing clearer, more detailed images.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on transducer design and the role of backing material in image quality.
Question #18
During a color Doppler scan, which angle to flow would most likely result in no color being visualized?
- A . 3 degrees
- B . 45 degrees
- C . 88 degrees
- D . 175 degrees
Correct Answer: C
C
Explanation:
Color Doppler imaging is most effective when the angle between the ultrasound beam and the flow of blood is small.
At an angle of 88 degrees, the flow of blood is nearly perpendicular to the ultrasound beam. When the angle is close to 90 degrees, the Doppler shift (frequency change) approaches zero, resulting in little to no color being visualized on the Doppler image.
Thus, to obtain a color signal, the angle should be optimized to be as close to 0 degrees as possible, with 60 degrees being the practical limit for accurate Doppler measurements.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on Doppler angle and its effect on Doppler imaging.
C
Explanation:
Color Doppler imaging is most effective when the angle between the ultrasound beam and the flow of blood is small.
At an angle of 88 degrees, the flow of blood is nearly perpendicular to the ultrasound beam. When the angle is close to 90 degrees, the Doppler shift (frequency change) approaches zero, resulting in little to no color being visualized on the Doppler image.
Thus, to obtain a color signal, the angle should be optimized to be as close to 0 degrees as possible, with 60 degrees being the practical limit for accurate Doppler measurements.
Reference: ARDMS Sonography Principles and Instrumentation guidelines on Doppler angle and its effect on Doppler imaging.
Question #19
In this image obtained from a tissue-mimicking phantom, which area of the sector is used to evaluate the dead zone?
- A . Option A
- B . Option B
- C . Option C
- D . Option D
Correct Answer: A
A
Explanation:
The dead zone in ultrasound imaging refers to the region closest to the transducer where imaging is not possible due to the high amplitude of the initial pulse. In a tissue-mimicking phantom, this is the area where no useful imaging data can be obtained. The purpose of evaluating the dead zone is to ensure that it is as small as possible to maximize the usable imaging depth. In the provided image, Option A represents the area closest to the transducer face, which is typically used to evaluate the dead zone. The other areas are further away and are used for evaluating other parameters such as resolution or depth penetration.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
A
Explanation:
The dead zone in ultrasound imaging refers to the region closest to the transducer where imaging is not possible due to the high amplitude of the initial pulse. In a tissue-mimicking phantom, this is the area where no useful imaging data can be obtained. The purpose of evaluating the dead zone is to ensure that it is as small as possible to maximize the usable imaging depth. In the provided image, Option A represents the area closest to the transducer face, which is typically used to evaluate the dead zone. The other areas are further away and are used for evaluating other parameters such as resolution or depth penetration.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
Question #20
Which resolution is degraded when utilizing multiple transmit focal zones?
- A . Temporal
- B . Lateral
- C . Axial
- D . Elevational
Correct Answer: A
A
Explanation:
When utilizing multiple transmit focal zones, the ultrasound system must perform multiple transmissions at each focal depth. This process requires more time for data acquisition, which in turn decreases the frame rate. A lower frame rate directly impacts temporal resolution, which is the ability to accurately depict moving structures over time. Thus, using multiple focal zones improves lateral resolution but degrades temporal resolution.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
A
Explanation:
When utilizing multiple transmit focal zones, the ultrasound system must perform multiple transmissions at each focal depth. This process requires more time for data acquisition, which in turn decreases the frame rate. A lower frame rate directly impacts temporal resolution, which is the ability to accurately depict moving structures over time. Thus, using multiple focal zones improves lateral resolution but degrades temporal resolution.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
Question #21
Which color Doppler setting can be optimized to eliminate low-frequency Doppler shifts without having any effect on higher Doppler frequency shifts?
- A . Gain
- B . Scale
- C . Wall filter
- D . Persistence
Correct Answer: C
C
Explanation:
The wall filter is used in color Doppler and spectral Doppler imaging to eliminate low-frequency Doppler shifts caused by tissue motion or vessel wall movement. Adjusting the wall filter removes these low-frequency signals without affecting higher-frequency Doppler shifts that represent blood flow. Other settings like gain, scale, and persistence do not selectively filter out low-frequency shifts in the same manner.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
C
Explanation:
The wall filter is used in color Doppler and spectral Doppler imaging to eliminate low-frequency Doppler shifts caused by tissue motion or vessel wall movement. Adjusting the wall filter removes these low-frequency signals without affecting higher-frequency Doppler shifts that represent blood flow. Other settings like gain, scale, and persistence do not selectively filter out low-frequency shifts in the same manner.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
Question #22
Which change improves temporal resolution during color flow imaging?
- A . Increase field of view
- B . Decrease transmit frequency
- C . Decrease packet size
- D . Increase line density
Correct Answer: C
C
Explanation:
Temporal resolution is improved by increasing the frame rate. One way to increase the frame rate is by decreasing the packet size (also known as ensemble length) in color Doppler imaging. The packet size refers to the number of pulses used to determine the Doppler shift at each location. A smaller packet size means fewer pulses are required, which allows for quicker data acquisition and thus a higher frame rate. Increasing the field of view, decreasing transmit frequency, and increasing line density would all decrease the frame rate and thus degrade temporal resolution.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
C
Explanation:
Temporal resolution is improved by increasing the frame rate. One way to increase the frame rate is by decreasing the packet size (also known as ensemble length) in color Doppler imaging. The packet size refers to the number of pulses used to determine the Doppler shift at each location. A smaller packet size means fewer pulses are required, which allows for quicker data acquisition and thus a higher frame rate. Increasing the field of view, decreasing transmit frequency, and increasing line density would all decrease the frame rate and thus degrade temporal resolution.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
Question #23
What does this image demonstrate?
- A . Presence of flow
- B . Direction of flow
- C . Color aliasing
- D . Color inversion
Correct Answer: C
C
Explanation:
Color aliasing in Doppler ultrasound occurs when the velocity of blood flow exceeds the Nyquist limit, causing the color display to wrap around and display high velocities incorrectly as the opposite direction. This phenomenon is characterized by a mix of colors that indicate flow in both directions at the same location. In the provided image, there is a clear presence of color aliasing, as evidenced by the abrupt color change across the vessel, which is not consistent with normal flow patterns.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
C
Explanation:
Color aliasing in Doppler ultrasound occurs when the velocity of blood flow exceeds the Nyquist limit, causing the color display to wrap around and display high velocities incorrectly as the opposite direction. This phenomenon is characterized by a mix of colors that indicate flow in both directions at the same location. In the provided image, there is a clear presence of color aliasing, as evidenced by the abrupt color change across the vessel, which is not consistent with normal flow patterns.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation guidelines.
Question #24
Which artifact is seen as a result of an increase in echo amplitude in the tissue located distal to an anechoic structure?
- A . Mirror image
- B . Reverberation
- C . Comet tail
- D . Enhancement
Correct Answer: D
D
Explanation:
Enhancement artifact occurs when an anechoic (or low-attenuation) structure, such as a cyst or fluid-filled structure, allows the ultrasound beam to pass through it with minimal attenuation. As a result, the tissues located distal to this anechoic structure appear brighter (increased echo amplitude) on the ultrasound image because the sound waves are less attenuated by the anechoic structure, leading to higher intensity echoes returning from the distal tissue. This increased brightness beyond the anechoic area is known as enhancement.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
D
Explanation:
Enhancement artifact occurs when an anechoic (or low-attenuation) structure, such as a cyst or fluid-filled structure, allows the ultrasound beam to pass through it with minimal attenuation. As a result, the tissues located distal to this anechoic structure appear brighter (increased echo amplitude) on the ultrasound image because the sound waves are less attenuated by the anechoic structure, leading to higher intensity echoes returning from the distal tissue. This increased brightness beyond the anechoic area is known as enhancement.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
Question #25
What is an advantage of power Doppler over color Doppler?
- A . Accurate velocity information
- B . Increased frame rate
- C . Diminished flash artifact
- D . Less angle dependent
Correct Answer: D
D
Explanation:
Power Doppler, unlike color Doppler, is less angle dependent because it detects the strength of the Doppler signal rather than the velocity of the blood flow. This means it is more sensitive to detecting low-velocity flow and flow in smaller vessels, regardless of the angle between the ultrasound beam and the flow direction. Color Doppler provides information on flow direction and velocity but is highly dependent on the angle of insonation, making it less reliable when the angle is suboptimal.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Zwiebel, W. J., & Pellerito, J. S. (2017). Introduction to Vascular Ultrasonography. Elsevier.
D
Explanation:
Power Doppler, unlike color Doppler, is less angle dependent because it detects the strength of the Doppler signal rather than the velocity of the blood flow. This means it is more sensitive to detecting low-velocity flow and flow in smaller vessels, regardless of the angle between the ultrasound beam and the flow direction. Color Doppler provides information on flow direction and velocity but is highly dependent on the angle of insonation, making it less reliable when the angle is suboptimal.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Zwiebel, W. J., & Pellerito, J. S. (2017). Introduction to Vascular Ultrasonography. Elsevier.
Question #26
What is effected by increasing the color scale?
- A . The Nyquist limit is increased
- B . More colors are displayed
- C . The color box width decreases
- D . The color priority decreases
Correct Answer: A
A
Explanation:
The Nyquist limit, which is the maximum detectable velocity before aliasing occurs, is directly related to the pulse repetition frequency (PRF). Increasing the color scale on the ultrasound machine effectively increases the PRF. When the PRF is increased, the Nyquist limit is also increased, allowing for the measurement of higher velocities without aliasing.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau, F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
A
Explanation:
The Nyquist limit, which is the maximum detectable velocity before aliasing occurs, is directly related to the pulse repetition frequency (PRF). Increasing the color scale on the ultrasound machine effectively increases the PRF. When the PRF is increased, the Nyquist limit is also increased, allowing for the measurement of higher velocities without aliasing.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau, F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
Question #27
Which change can be made in order to avoid exceeding the Nyquist limit?
- A . Increase output power
- B . Decrease output power
- C . Increase pulse repetition frequency
- D . Decrease pulse repetition frequency
Correct Answer: C
C
Explanation:
To avoid exceeding the Nyquist limit and prevent aliasing in Doppler ultrasound, the pulse repetition frequency (PRF) should be increased. The Nyquist limit is half of the PRF, so by increasing the PRF, the Nyquist limit is raised, allowing the system to accurately measure higher velocities without encountering aliasing artifacts.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Zwiebel, W. J., & Pellerito, J. S. (2017). Introduction to Vascular Ultrasonography. Elsevier.
C
Explanation:
To avoid exceeding the Nyquist limit and prevent aliasing in Doppler ultrasound, the pulse repetition frequency (PRF) should be increased. The Nyquist limit is half of the PRF, so by increasing the PRF, the Nyquist limit is raised, allowing the system to accurately measure higher velocities without encountering aliasing artifacts.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Zwiebel, W. J., & Pellerito, J. S. (2017). Introduction to Vascular Ultrasonography. Elsevier.
Question #28
What determines the resonant frequency of a pulsed wave transducer?
- A . Element thickness and pulse repetition frequency
- B . Element diameter and speed of sound in element
- C . Element diameter and element thickness
- D . Element thickness and speed of sound in element
Correct Answer: D
D
Explanation:
The resonant frequency of a pulsed wave transducer is determined by the thickness of the piezoelectric element and the speed of sound within that element. The resonant frequency is inversely proportional to the element thickness and directly proportional to the speed of sound in the material. Thinner elements and higher sound speeds result in higher resonant frequencies, while thicker elements and lower sound speeds result in lower resonant frequencies.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
D
Explanation:
The resonant frequency of a pulsed wave transducer is determined by the thickness of the piezoelectric element and the speed of sound within that element. The resonant frequency is inversely proportional to the element thickness and directly proportional to the speed of sound in the material. Thinner elements and higher sound speeds result in higher resonant frequencies, while thicker elements and lower sound speeds result in lower resonant frequencies.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
Question #29
Which factor does a string phantom evaluate?
- A . Two-dimensional resolution
- B . Intensity values
- C . Flow velocity
- D . Slice thickness
Correct Answer: C
C
Explanation:
A string phantom is designed to evaluate the accuracy of Doppler ultrasound systems, specifically in measuring flow velocity. It consists of a moving string or filament that mimics blood flow within a vessel. By using this phantom, sonographers can assess how accurately the ultrasound system can detect and measure the speed of the moving target. This helps in calibrating and verifying the performance of Doppler systems, ensuring they provide accurate flow velocity readings in clinical practice.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation study materials.
Textbook of Diagnostic Sonography by Hagen-Ansert, S. L. (latest edition).
C
Explanation:
A string phantom is designed to evaluate the accuracy of Doppler ultrasound systems, specifically in measuring flow velocity. It consists of a moving string or filament that mimics blood flow within a vessel. By using this phantom, sonographers can assess how accurately the ultrasound system can detect and measure the speed of the moving target. This helps in calibrating and verifying the performance of Doppler systems, ensuring they provide accurate flow velocity readings in clinical practice.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation study materials.
Textbook of Diagnostic Sonography by Hagen-Ansert, S. L. (latest edition).
Question #30
Which resolution is improved by focusing?
- A . Lateral
- B . Axial
- C . Temporal
- D . Contrast
Correct Answer: A
A
Explanation:
Focusing improves lateral resolution in ultrasound imaging. Lateral resolution refers to the system’s ability to distinguish between two points that are side by side (perpendicular to the sound beam’s path). By focusing the ultrasound beam, the width of the beam is narrowed at the focal point, enhancing the system’s ability to resolve structures that are close together in the lateral plane. This results in clearer, more detailed images of the anatomical structures.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation study materials.
Diagnostic Ultrasound: Principles and Instruments by Kremkau, F. W. (latest edition).
A
Explanation:
Focusing improves lateral resolution in ultrasound imaging. Lateral resolution refers to the system’s ability to distinguish between two points that are side by side (perpendicular to the sound beam’s path). By focusing the ultrasound beam, the width of the beam is narrowed at the focal point, enhancing the system’s ability to resolve structures that are close together in the lateral plane. This results in clearer, more detailed images of the anatomical structures.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation study materials.
Diagnostic Ultrasound: Principles and Instruments by Kremkau, F. W. (latest edition).
Question #31
The calipers in this image measure which performance characteristic of a system?
- A . Depth measurement accuracy
- B . Dynamic range
- C . Axial resolution
- D . Lateral resolution
Correct Answer: A
A
Explanation:
The calipers shown in the image are used to measure the depth of structures within the ultrasound image. This performance characteristic, known as depth measurement accuracy, assesses how accurately the ultrasound system can measure the distance from the transducer to a specific point within the body. Accurate depth measurements are crucial for diagnostic purposes, ensuring that anatomical and pathological structures are correctly identified and evaluated.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation study materials.
Textbook of Diagnostic Sonography by Hagen-Ansert, S. L. (latest edition).
A
Explanation:
The calipers shown in the image are used to measure the depth of structures within the ultrasound image. This performance characteristic, known as depth measurement accuracy, assesses how accurately the ultrasound system can measure the distance from the transducer to a specific point within the body. Accurate depth measurements are crucial for diagnostic purposes, ensuring that anatomical and pathological structures are correctly identified and evaluated.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation study materials.
Textbook of Diagnostic Sonography by Hagen-Ansert, S. L. (latest edition).
Question #32
In this image, which artifact is demonstrated?
- A . Mirroring
- B . Aliasing
- C . Range ambiguity
- D . Spectral broadening
Correct Answer: A
A
Explanation:
The artifact demonstrated in the image is mirroring. This occurs when the ultrasound beam encounters a strong reflector, such as a diaphragm or pleura, and is reflected back and forth between the object and the transducer. This results in a duplicate image appearing on the other side of the strong reflector, creating a mirror image artifact. It is crucial for sonographers to recognize and differentiate this artifact from actual anatomical structures to avoid misinterpretation.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation study materials.
Diagnostic Ultrasound: Principles and Instruments by Kremkau, F. W. (latest edition).
A
Explanation:
The artifact demonstrated in the image is mirroring. This occurs when the ultrasound beam encounters a strong reflector, such as a diaphragm or pleura, and is reflected back and forth between the object and the transducer. This results in a duplicate image appearing on the other side of the strong reflector, creating a mirror image artifact. It is crucial for sonographers to recognize and differentiate this artifact from actual anatomical structures to avoid misinterpretation.
Reference: American Registry for Diagnostic Medical Sonography (ARDMS) Sonography Principles and Instrumentation study materials.
Diagnostic Ultrasound: Principles and Instruments by Kremkau, F. W. (latest edition).
Question #33
What is a potential negative consequence of using a high wall filter?
- A . Desired signal may be eliminated
- B . Aliasing could occur
- C . Penetration is reduced
- D . Too much noise may appear on the image
Correct Answer: A
A
Explanation:
A high wall filter is used in Doppler ultrasound to eliminate low-frequency signals that may be attributed to vessel wall motion or other low-velocity flows. However, if the wall filter is set too high, it can inadvertently eliminate desired low-frequency Doppler signals that represent real blood flow, particularly in smaller vessels or those with slower flow velocities. This results in a loss of valuable diagnostic information.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Review, Doppler Ultrasound section.
A
Explanation:
A high wall filter is used in Doppler ultrasound to eliminate low-frequency signals that may be attributed to vessel wall motion or other low-velocity flows. However, if the wall filter is set too high, it can inadvertently eliminate desired low-frequency Doppler signals that represent real blood flow, particularly in smaller vessels or those with slower flow velocities. This results in a loss of valuable diagnostic information.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Review, Doppler Ultrasound section.
Question #34
During 3-D volume acquisition, the quality of the images is most dependent upon which factor?
- A . Number of slices acquired
- B . Power output
- C . Rendering method utilized
- D . Speed of post-processing image compression
Correct Answer: A
A
Explanation:
During 3-D volume acquisition in ultrasound, the quality of the images is most dependent on the number of slices acquired. This is because the more slices (or planes) that are captured, the more detailed and accurate the reconstruction of the 3-D volume will be. This allows for better spatial resolution and more precise visualization of anatomical structures. Other factors, such as power output, rendering methods, and speed of post-processing, also affect image quality but are secondary to the number of slices in terms of fundamental image acquisition quality.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Review, 3-D Ultrasound Imaging section.
A
Explanation:
During 3-D volume acquisition in ultrasound, the quality of the images is most dependent on the number of slices acquired. This is because the more slices (or planes) that are captured, the more detailed and accurate the reconstruction of the 3-D volume will be. This allows for better spatial resolution and more precise visualization of anatomical structures. Other factors, such as power output, rendering methods, and speed of post-processing, also affect image quality but are secondary to the number of slices in terms of fundamental image acquisition quality.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Review, 3-D Ultrasound Imaging section.
Question #35
What occurs when the pulse repetition frequency is less than twice the Doppler shift frequency?
- A . Spectral broadening
- B . Range ambiguity
- C . Aliasing
- D . Propagation speed artifact
Correct Answer: C
C
Explanation:
Aliasing occurs in Doppler ultrasound when the pulse repetition frequency (PRF) is less than twice the Doppler shift frequency (Nyquist limit). When this condition is met, the Doppler signals are not sampled frequently enough to accurately measure the frequency shifts, resulting in the misrepresentation of the flow velocities. This causes the aliasing artifact, where high-velocity flows are displayed incorrectly as wrapping around the baseline, leading to potential diagnostic errors.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Review, Doppler Artifacts section.
C
Explanation:
Aliasing occurs in Doppler ultrasound when the pulse repetition frequency (PRF) is less than twice the Doppler shift frequency (Nyquist limit). When this condition is met, the Doppler signals are not sampled frequently enough to accurately measure the frequency shifts, resulting in the misrepresentation of the flow velocities. This causes the aliasing artifact, where high-velocity flows are displayed incorrectly as wrapping around the baseline, leading to potential diagnostic errors.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Review, Doppler Artifacts section.
Question #36
A Doppler shift is 10,000 Hz at an angle of flow of 60 degrees.
What is the Doppler shift at 0 degrees?
- A . 20,000 Hz
- B . 10,000 Hz
- C . 5,000 Hz
- D . 2,500 Hz
Correct Answer: A
A
Explanation:
depends on the angle between the ultrasound beam and the direction of blood flow. The Doppler equation includes a cosine function of the angle of insonation (θ). At 60 degrees, the cosine is 0.5, and at 0 degrees (parallel to the flow), the cosine is 1. Thus, if the Doppler shift is 10,000 Hz at 60 degrees, it would double to 20,000 Hz at 0 degrees because the cosine of 0 degrees is 1 (cos(0°) = 1) and the cosine of 60 degrees is 0.5 (cos(60°) = 0.5). The formula is: Doppler shift at 0 degrees = Doppler shift at 60 degrees / cos(60 degrees) = 10,000 Hz / 0.5 = 20,000 Hz.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Review, Doppler Shift and Angle of Insonation section.
A
Explanation:
depends on the angle between the ultrasound beam and the direction of blood flow. The Doppler equation includes a cosine function of the angle of insonation (θ). At 60 degrees, the cosine is 0.5, and at 0 degrees (parallel to the flow), the cosine is 1. Thus, if the Doppler shift is 10,000 Hz at 60 degrees, it would double to 20,000 Hz at 0 degrees because the cosine of 0 degrees is 1 (cos(0°) = 1) and the cosine of 60 degrees is 0.5 (cos(60°) = 0.5). The formula is: Doppler shift at 0 degrees = Doppler shift at 60 degrees / cos(60 degrees) = 10,000 Hz / 0.5 = 20,000 Hz.
Reference: ARDMS Sonography Principles and Instrumentation (SPI) Review, Doppler Shift and Angle of Insonation section.
Question #37
Which unfocused transducer will have the greatest divergence?
- A . 4 mm aperture, 4 MHz
- B . 4 mm aperture, 6 MHz
- C . 6 mm aperture, 4 MHz
- D . 6 mm aperture, 6 MHz
Correct Answer: A
A
Explanation:
Transducer beam divergence is influenced by the aperture size and frequency. A smaller aperture and lower frequency result in greater beam divergence. Among the given options, the transducer with a 4 mm aperture and 4 MHz frequency will have the greatest divergence. This is because the smaller aperture size contributes to a wider beam spread, and the lower frequency also increases the divergence compared to higher frequencies.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
A
Explanation:
Transducer beam divergence is influenced by the aperture size and frequency. A smaller aperture and lower frequency result in greater beam divergence. Among the given options, the transducer with a 4 mm aperture and 4 MHz frequency will have the greatest divergence. This is because the smaller aperture size contributes to a wider beam spread, and the lower frequency also increases the divergence compared to higher frequencies.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
Question #38
What happens to the amount of attenuation if the path length is doubled?
- A . Quadrupled
- B . Doubled
- C . Halved
- D . Quartered
Correct Answer: B
B
Explanation:
Attenuation in ultrasound is directly proportional to the path length. If the path length is doubled, the amount of attenuation is also doubled. Attenuation refers to the reduction in the amplitude and intensity of the ultrasound wave as it travels through tissue, primarily due to absorption, reflection, and scattering. The relationship is linear, so doubling the distance the sound wave travels will result in twice the amount of attenuation.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
B
Explanation:
Attenuation in ultrasound is directly proportional to the path length. If the path length is doubled, the amount of attenuation is also doubled. Attenuation refers to the reduction in the amplitude and intensity of the ultrasound wave as it travels through tissue, primarily due to absorption, reflection, and scattering. The relationship is linear, so doubling the distance the sound wave travels will result in twice the amount of attenuation.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.
Question #39
Which type of resolution will be improved by decreasing the depth of field?
- A . Lateral
- B . Temporal
- C . Axial
- D . Elevational
Correct Answer: A
A
Explanation:
Lateral resolution refers to the ability to distinguish two structures that are side by side. It is dependent on the width of the ultrasound beam. By decreasing the depth of field, the beam width is reduced at any given point along the depth, which improves the lateral resolution. This is because a narrower beam can better distinguish between objects that are close together laterally.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments.
A
Explanation:
Lateral resolution refers to the ability to distinguish two structures that are side by side. It is dependent on the width of the ultrasound beam. By decreasing the depth of field, the beam width is reduced at any given point along the depth, which improves the lateral resolution. This is because a narrower beam can better distinguish between objects that are close together laterally.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Kremkau,
F. W. (2015). Diagnostic Ultrasound: Principles and Instruments.
Question #40
What improves the temporal resolution of color flow imaging?
- A . Decreasing pulse repetition frequency
- B . Increasing ensemble length (packet size)
- C . Decreasing width of the color field of view
- D . Increasing number of color lines per frame
Correct Answer: C
C
Explanation:
Temporal resolution refers to the ability of the ultrasound system to distinguish events occurring closely in time. In color flow imaging, temporal resolution is affected by the frame rate, which can be increased by decreasing the width of the color field of view. This is because a narrower color field requires fewer scan lines to be processed, allowing for more frames to be captured per second.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Edelman, S. K. (2017). Understanding Ultrasound Physics.
C
Explanation:
Temporal resolution refers to the ability of the ultrasound system to distinguish events occurring closely in time. In color flow imaging, temporal resolution is affected by the frame rate, which can be increased by decreasing the width of the color field of view. This is because a narrower color field requires fewer scan lines to be processed, allowing for more frames to be captured per second.
Reference: ARDMS Sonography Principles and Instrumentation guidelines Edelman, S. K. (2017). Understanding Ultrasound Physics.