Podcast
Questions and Answers
What is dynamic aperture?
What is dynamic aperture?
- Aperture that varies with transmit frequency (correct)
- Aperture that increases with increasing focal length
- Aperture that changes as a function of frame rate
- Aperture that decreases as a function of time
To which acoustic variable is penetration depth inversely related?
To which acoustic variable is penetration depth inversely related?
- Period
- Frequency (correct)
- Propagation speed
- Wavelength
Which imaging mode requires a broadband transducer?
Which imaging mode requires a broadband transducer?
- Harmonic imaging
- Color flow imaging
- Continuous wave Doppler
- Pulsed wave Doppler (correct)
What is the Doppler shift frequency?
What is the Doppler shift frequency?
What is the potential effect of increasing the pulse repetition frequency (PRF)?
What is the potential effect of increasing the pulse repetition frequency (PRF)?
What is an advantage of using pulsed wave Doppler compared to continuous wave Doppler?
What is an advantage of using pulsed wave Doppler compared to continuous wave Doppler?
What affects the beam width in the near field?
What affects the beam width in the near field?
What is the advantage of using pulsed-wave Doppler versus continuous-wave Doppler?
What is the advantage of using pulsed-wave Doppler versus continuous-wave Doppler?
Which parameter is target group C evaluating based on the image?
Which parameter is target group C evaluating based on the image?
In this image, which target group is used to evaluate dead zone?
In this image, which target group is used to evaluate dead zone?
Which ultrasound parameter directly affects an ultrasound beam's intensity?
Which ultrasound parameter directly affects an ultrasound beam's intensity?
The center frequency of a transducer depends primarily upon which characteristics of the crystal?
The center frequency of a transducer depends primarily upon which characteristics of the crystal?
Which factor limits image frame rate?
Which factor limits image frame rate?
When using a 5 MHz transducer, in which tissue is the ultrasound wavelength shortest?
When using a 5 MHz transducer, in which tissue is the ultrasound wavelength shortest?
Which term describes the averaging together of scan lines from multiple angles to create one image?
Which term describes the averaging together of scan lines from multiple angles to create one image?
Which variable can cause an acoustic shadow artifact?
Which variable can cause an acoustic shadow artifact?
What does coded excitation improve in addition to penetration?
What does coded excitation improve in addition to penetration?
How is lateral resolution determined for a pulsed-echo system using a tissue-mimicking test object?
How is lateral resolution determined for a pulsed-echo system using a tissue-mimicking test object?
Which variable caused the color change from blue to red of the vessel in this image?
Which variable caused the color change from blue to red of the vessel in this image?
Which artifact is indicated by the arrows in this image?
Which artifact is indicated by the arrows in this image?
Which control improves the effects of attenuation?
Which control improves the effects of attenuation?
Which Doppler angle to flow results in the greatest absolute Doppler shift?
Which Doppler angle to flow results in the greatest absolute Doppler shift?
What term describes blood flow changes in response to respiration?
What term describes blood flow changes in response to respiration?
An increase in which parameter will improve the accuracy of velocity measurements with autocorrelation?
An increase in which parameter will improve the accuracy of velocity measurements with autocorrelation?
Which harmonic imaging, how does echo frequency relate to transmitted frequency?
Which harmonic imaging, how does echo frequency relate to transmitted frequency?
Which change would minimize the artifact observed in this image, assuming the pulse repetition frequency is at its maximum limit?
Which change would minimize the artifact observed in this image, assuming the pulse repetition frequency is at its maximum limit?
Which parameter is most likely to affect spatial resolution?
Which parameter is most likely to affect spatial resolution?
Which imaging modality can provide the most accurate measurement of tumor volume?
Which imaging modality can provide the most accurate measurement of tumor volume?
According to ALARA (as low as reasonably achievable) guidelines, which parameter should be minimized?
According to ALARA (as low as reasonably achievable) guidelines, which parameter should be minimized?
What is an advantage of using pulsed-wave Doppler versus continuous wave Doppler?
What is an advantage of using pulsed-wave Doppler versus continuous wave Doppler?
What is demonstrated in this image produced by a linear array transducer placed on a uniform tissue-mimicking phantom?
What is demonstrated in this image produced by a linear array transducer placed on a uniform tissue-mimicking phantom?
What is the distance to the interface if the round trip time for a sound wave is 39 microseconds?
What is the distance to the interface if the round trip time for a sound wave is 39 microseconds?
Which signals are eliminated by the wall filter in a spectral Doppler display?
Which signals are eliminated by the wall filter in a spectral Doppler display?
At minimum, what is required when documenting a pathology discovered during an examination?
At minimum, what is required when documenting a pathology discovered during an examination?
If the diameter of the sound beam is halved by focusing, what happens to the intensity?
If the diameter of the sound beam is halved by focusing, what happens to the intensity?
Which parameter would change on a phantom test if the spatial pulse length were made longer?
Which parameter would change on a phantom test if the spatial pulse length were made longer?
If the ultrasound machine comes in contact with a patient's body fluids, what should be done?
If the ultrasound machine comes in contact with a patient's body fluids, what should be done?
Which parameter is most related to cavitation tissue?
Which parameter is most related to cavitation tissue?
Which interface will cause the maximum reflection of the incident sound beam?
Which interface will cause the maximum reflection of the incident sound beam?
Acoustic enhancement occurs distal to what?
Acoustic enhancement occurs distal to what?
As the pressure amplitude of ultrasound doubles, what happens to the wavelength?
As the pressure amplitude of ultrasound doubles, what happens to the wavelength?
What is the period of a 5 MHz ultrasound wave?
What is the period of a 5 MHz ultrasound wave?
What limits diagnostic application at higher frequencies?
What limits diagnostic application at higher frequencies?
What is the function of a lens on a transducer?
What is the function of a lens on a transducer?
What would improve axial resolution?
What would improve axial resolution?
What is true of the far field?
What is true of the far field?
What improves lateral resolution?
What improves lateral resolution?
Which statement is true for a linear phased array transducer?
Which statement is true for a linear phased array transducer?
Which artifact is commonly seen within cystic masses due to the finite dimensions of the ultrasound beam?
Which artifact is commonly seen within cystic masses due to the finite dimensions of the ultrasound beam?
Which technique utilizes frequency modulation of the transmitted pulse to improve signal to noise ratio?
Which technique utilizes frequency modulation of the transmitted pulse to improve signal to noise ratio?
What is varied to implement apodization?
What is varied to implement apodization?
What will produce no Doppler shift at a receiver?
What will produce no Doppler shift at a receiver?
Which mode requires two elements mounted side by side?
Which mode requires two elements mounted side by side?
When employing a tissue mimicking phantom, the depth at which echoes are no longer detected is an indicator of what?
When employing a tissue mimicking phantom, the depth at which echoes are no longer detected is an indicator of what?
What enhances the transmission of ultrasound energy between the transducer and the skin?
What enhances the transmission of ultrasound energy between the transducer and the skin?
Which technique increases the sharpness of high contrast boundaries?
Which technique increases the sharpness of high contrast boundaries?
What is the most appropriate action for the sonographer to take when receiving a verbal order for an exam?
What is the most appropriate action for the sonographer to take when receiving a verbal order for an exam?
Which setting of an ultrasound system gives the sonographer the ability to display both strong and weak echoes?
Which setting of an ultrasound system gives the sonographer the ability to display both strong and weak echoes?
What is a benefit of using contrast agents?
What is a benefit of using contrast agents?
A sound wave propagates fastest through which substance?
A sound wave propagates fastest through which substance?
When the focal point in a B-mode image is electronically changed, which type of focusing is in use?
When the focal point in a B-mode image is electronically changed, which type of focusing is in use?
When a fluid is flowing at a slow and constant rate within a long tube having a uniform diameter, what is the nature of the flow?
When a fluid is flowing at a slow and constant rate within a long tube having a uniform diameter, what is the nature of the flow?
What causes range ambiguity artifacts?
What causes range ambiguity artifacts?
What is the round trip time in soft tissue for an echo from a reflector at a depth of 1 cm?
What is the round trip time in soft tissue for an echo from a reflector at a depth of 1 cm?
Which variable decreases when the number of acoustic lines per frame is increased without changing its maximum depth?
Which variable decreases when the number of acoustic lines per frame is increased without changing its maximum depth?
Frequency compounding improves image quality by doing what?
Frequency compounding improves image quality by doing what?
What is the most common cause of localized vertical nonuniformity in a real-time B-mode image?
What is the most common cause of localized vertical nonuniformity in a real-time B-mode image?
What is the cause of the black region in the center of the vessel seen in this image?
What is the cause of the black region in the center of the vessel seen in this image?
What is increased if the pulse duration is decreased?
What is increased if the pulse duration is decreased?
What is the Nyquist limit if a pulsed wave Doppler instrument has a pulse repetition frequency of 16 kHz?
What is the Nyquist limit if a pulsed wave Doppler instrument has a pulse repetition frequency of 16 kHz?
What caused the color pattern demonstrated in the artery indicated by the arrow in this image?
What caused the color pattern demonstrated in the artery indicated by the arrow in this image?
Which adjustment should be made to avoid the aliasing displayed on this spectral Doppler image seen on spectral analysis?
Which adjustment should be made to avoid the aliasing displayed on this spectral Doppler image seen on spectral analysis?
If red blood cells are approaching a 5 MHz Doppler transducer at a speed of 75 cm/s, what is the approximate received ultrasound frequency?
If red blood cells are approaching a 5 MHz Doppler transducer at a speed of 75 cm/s, what is the approximate received ultrasound frequency?
Which condition must be present for refraction to occur?
Which condition must be present for refraction to occur?
The thermal index (TI) is most affected by which type of interaction between sound and tissue?
The thermal index (TI) is most affected by which type of interaction between sound and tissue?
In an unfocused transducer, what is the region between the transducer face and the point where the beam diverges?
In an unfocused transducer, what is the region between the transducer face and the point where the beam diverges?
What is this artifact?
What is this artifact?
How do you fix this?
How do you fix this?
Which way is the blood flowing?
Which way is the blood flowing?
Study Notes
Dynamic Aperture and Imaging Modes
- Dynamic aperture varies with transmit frequency, affecting imaging quality as focal length changes.
- Penetration depth is inversely related to frequency; higher frequencies result in lower penetration.
- Pulsed wave Doppler requires broadband transducers, essential for capturing detailed blood flow information.
Doppler Shift and Pulse Repetition Frequency
- Doppler shift frequency is the difference between transmitted and received ultrasound frequencies, critical for measuring flow velocities.
- Increasing pulse repetition frequency (PRF) can lead to depth ambiguity, complicating signal interpretation, while also affecting frame rate.
Imaging Parameters and Artifacts
- Near field beam width is influenced by transducer aperture, impacting image resolution.
- Dead zone evaluation is crucial for diagnostic accuracy; it determines areas where no echoes are received, leading to potential interpretation errors.
- Coded excitation enhances penetration and improves the signal-to-noise ratio in Doppler imaging.
Resolution and Acoustic Variables
- Axial resolution is determined by pulse length; shorter pulses yield better resolution.
- Lateral resolution is improved by decreasing beam width, enhancing the clarity of structures in the imaging plane.
- The acoustic shadow artifact occurs due to high acoustic impedance mismatches, while acoustic enhancement occurs distal to weakly attenuating structures.
Transducer Characteristics and Frequency Relationships
- Transducer center frequency primarily depends on crystal thickness, influencing image quality and depth of visualization.
- Higher frequencies offer better resolution but are limited by penetration capabilities in soft tissue.
- Frequency modulation techniques like coded excitation can augment imaging quality through enhanced signal capture.
Doppler Characteristics and Blood Flow
- The greatest absolute Doppler shift occurs at a 0-degree angle to flow, essential for accurate velocity measurements.
- Phasic blood flow changes occur in response to respiration, impacting the interpretation of Doppler signals.
- Increased packet size improves velocity measurement accuracy, particularly in power Doppler imaging.
Artifacts and Image Interpretation
- Range ambiguity artifacts result from overly high PRF, leading to confusion in depth interpretation.
- Specific artifacts like mirror image and reverberation can confuse diagnosis and must be recognized for proper image assessment.
- Resolving color aliasing involves adjustments such as decreasing transducer frequency or repositioning sample volumes.
Safety and Operational Practices
- ALARA principles recommend minimizing transmit power to reduce patient exposure while maintaining image quality.
- Infectious protocols must be adhered to when ultrasound machines come into contact with bodily fluids to ensure safety and reliability.
Practical Applications and Technical Knowledge
- Understanding the behavior of sound waves in different mediums, such as bone and fat, is essential for accurate imaging and diagnosis.
- Training and experience contribute significantly to recognizing and correcting parameters affecting image quality, like dynamic range and gain settings.
Studying That Suits You
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Test your knowledge with SPI practice flashcards focusing on ARDMS A & B topics. Dive into key concepts like dynamic aperture and acoustic variable relations. Perfect for students preparing for their SPI certification.
