SPI Practice Flashcards (ARDMS A & B)

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Questions and Answers

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?

Period

Frequency (correct)

Propagation speed

Wavelength

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?

Difference between the transmitted ultrasound frequency and the received ultrasound frequency Signup and view all the answers

What is the potential effect of increasing the pulse repetition frequency (PRF)?

Depth ambiguity Signup and view all the answers

What is an advantage of using pulsed wave Doppler compared to continuous wave Doppler?

Ability to select sample depth Signup and view all the answers

What affects the beam width in the near field?

Transducer aperture Signup and view all the answers

What is the advantage of using pulsed-wave Doppler versus continuous-wave Doppler?

Provides depth specificity Signup and view all the answers

Which parameter is target group C evaluating based on the image?

Dead zone Signup and view all the answers

In this image, which target group is used to evaluate dead zone?

Target Group A Signup and view all the answers

Which ultrasound parameter directly affects an ultrasound beam's intensity?

Output power Signup and view all the answers

The center frequency of a transducer depends primarily upon which characteristics of the crystal?

Thickness Signup and view all the answers

Which factor limits image frame rate?

Sample volume size Signup and view all the answers

When using a 5 MHz transducer, in which tissue is the ultrasound wavelength shortest?

Bone Signup and view all the answers

Which term describes the averaging together of scan lines from multiple angles to create one image?

Spatial compounding Signup and view all the answers

Which variable can cause an acoustic shadow artifact?

Small acoustic impedance mismatch Signup and view all the answers

What does coded excitation improve in addition to penetration?

Signal-to-noise ratio Signup and view all the answers

How is lateral resolution determined for a pulsed-echo system using a tissue-mimicking test object?

By observing spaces between reflectors perpendicular to the beam Signup and view all the answers

Which variable caused the color change from blue to red of the vessel in this image?

Change in vessel direction Signup and view all the answers

Which artifact is indicated by the arrows in this image?

Comet tail Signup and view all the answers

Which control improves the effects of attenuation?

Time gain compensation Signup and view all the answers

Which Doppler angle to flow results in the greatest absolute Doppler shift?

0 degrees Signup and view all the answers

What term describes blood flow changes in response to respiration?

Phasic Signup and view all the answers

An increase in which parameter will improve the accuracy of velocity measurements with autocorrelation?

Packet size Signup and view all the answers

Which harmonic imaging, how does echo frequency relate to transmitted frequency?

Twice the transmitted frequency Signup and view all the answers

Which change would minimize the artifact observed in this image, assuming the pulse repetition frequency is at its maximum limit?

Adjust the baseline Signup and view all the answers

Which parameter is most likely to affect spatial resolution?

Beam width Signup and view all the answers

Which imaging modality can provide the most accurate measurement of tumor volume?

B-mode Signup and view all the answers

According to ALARA (as low as reasonably achievable) guidelines, which parameter should be minimized?

Transmit power Signup and view all the answers

What is an advantage of using pulsed-wave Doppler versus continuous wave Doppler?

Provides depth specificity Signup and view all the answers

What is demonstrated in this image produced by a linear array transducer placed on a uniform tissue-mimicking phantom?

Transducer crystals are damaged Signup and view all the answers

What is the distance to the interface if the round trip time for a sound wave is 39 microseconds?

3 cm Signup and view all the answers

Which signals are eliminated by the wall filter in a spectral Doppler display?

Low frequency, low amplitude Signup and view all the answers

At minimum, what is required when documenting a pathology discovered during an examination?

Two images demonstrating the same pathology from different scan planes Signup and view all the answers

If the diameter of the sound beam is halved by focusing, what happens to the intensity?

Increased by 2 times Signup and view all the answers

Which parameter would change on a phantom test if the spatial pulse length were made longer?

Axial resolution Signup and view all the answers

If the ultrasound machine comes in contact with a patient's body fluids, what should be done?

Use an approved disinfectant solution to clean it Signup and view all the answers

Which parameter is most related to cavitation tissue?

Pressure Signup and view all the answers

Which interface will cause the maximum reflection of the incident sound beam?

Soft tissue/bone Signup and view all the answers

Acoustic enhancement occurs distal to what?

Weakly attenuating structure Signup and view all the answers

As the pressure amplitude of ultrasound doubles, what happens to the wavelength?

Unchanged Signup and view all the answers

What is the period of a 5 MHz ultrasound wave?

0.02 ms Signup and view all the answers

What limits diagnostic application at higher frequencies?

Tissue penetration Signup and view all the answers

What is the function of a lens on a transducer?

Focus the beam Signup and view all the answers

What would improve axial resolution?

Increase the transducer frequency Signup and view all the answers

What is true of the far field?

Sound beam diverges Signup and view all the answers

What improves lateral resolution?

Decreasing the beam width Signup and view all the answers

Which statement is true for a linear phased array transducer?

Elements are fired in successive groups Signup and view all the answers

Which artifact is commonly seen within cystic masses due to the finite dimensions of the ultrasound beam?

Slice thickness Signup and view all the answers

Which technique utilizes frequency modulation of the transmitted pulse to improve signal to noise ratio?

Coded excitation Signup and view all the answers

What is varied to implement apodization?

Voltage applied to each element Signup and view all the answers

What will produce no Doppler shift at a receiver?

Source and receiver moving at the same speed and direction Signup and view all the answers

Which mode requires two elements mounted side by side?

Continuous wave Doppler Signup and view all the answers

When employing a tissue mimicking phantom, the depth at which echoes are no longer detected is an indicator of what?

Sensitivity Signup and view all the answers

What enhances the transmission of ultrasound energy between the transducer and the skin?

The transducer matching layer Signup and view all the answers

Which technique increases the sharpness of high contrast boundaries?

Edge enhancement Signup and view all the answers

What is the most appropriate action for the sonographer to take when receiving a verbal order for an exam?

Verbally repeat the request back to the referrer to verify correctness Signup and view all the answers

Which setting of an ultrasound system gives the sonographer the ability to display both strong and weak echoes?

Dynamic range Signup and view all the answers

What is a benefit of using contrast agents?

Increased amplitude of the returning Doppler signals Signup and view all the answers

A sound wave propagates fastest through which substance?

Bone Signup and view all the answers

When the focal point in a B-mode image is electronically changed, which type of focusing is in use?

Dynamic Signup and view all the answers

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?

Laminar Signup and view all the answers

What causes range ambiguity artifacts?

PRF too high Signup and view all the answers

What is the round trip time in soft tissue for an echo from a reflector at a depth of 1 cm?

13 usec Signup and view all the answers

Which variable decreases when the number of acoustic lines per frame is increased without changing its maximum depth?

Frame rate Signup and view all the answers

Frequency compounding improves image quality by doing what?

Reducing speckle Signup and view all the answers

What is the most common cause of localized vertical nonuniformity in a real-time B-mode image?

Improper TGC Signup and view all the answers

What is the cause of the black region in the center of the vessel seen in this image?

Lack of blood flow at that location Signup and view all the answers

What is increased if the pulse duration is decreased?

Bandwidth Signup and view all the answers

What is the Nyquist limit if a pulsed wave Doppler instrument has a pulse repetition frequency of 16 kHz?

32 kHz Signup and view all the answers

What caused the color pattern demonstrated in the artery indicated by the arrow in this image?

Aliasing Signup and view all the answers

Which adjustment should be made to avoid the aliasing displayed on this spectral Doppler image seen on spectral analysis?

Decrease the transducer frequency Signup and view all the answers

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?

5,005 kHz Signup and view all the answers

Which condition must be present for refraction to occur?

Difference in tissue propagation speeds Signup and view all the answers

The thermal index (TI) is most affected by which type of interaction between sound and tissue?

Absorption Signup and view all the answers

In an unfocused transducer, what is the region between the transducer face and the point where the beam diverges?

Near field Signup and view all the answers

What is this artifact?

Reverberation Signup and view all the answers

How do you fix this?

Increase the color scale Signup and view all the answers

Which way is the blood flowing?

Bidirectional Signup and view all the answers

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.

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Description

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.