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Questions and Answers
Which gain will increase the risk of bioeffects?
Which gain will increase the risk of bioeffects?
Which of the following is considered the memory of an ultrasound instrument?
Which of the following is considered the memory of an ultrasound instrument?
Spectral broadening suggests:
Spectral broadening suggests:
With pulse wave Doppler, axial resolution:
With pulse wave Doppler, axial resolution:
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What color is usually used in color flow Doppler variance maps to indicate turbulent flow?
What color is usually used in color flow Doppler variance maps to indicate turbulent flow?
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Doppler high pass filter eliminates:
Doppler high pass filter eliminates:
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The Doppler wall filter is considered a:
The Doppler wall filter is considered a:
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The Nyquist Limit is equal to:
The Nyquist Limit is equal to:
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Multiple echoes, equally spaced originating from a gas bubble is called:
Multiple echoes, equally spaced originating from a gas bubble is called:
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An increase in red blood cell velocity will _____ the Doppler Shift:
An increase in red blood cell velocity will _____ the Doppler Shift:
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The primary advantage of CW Doppler is:
The primary advantage of CW Doppler is:
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The range for ultrasound begins:
The range for ultrasound begins:
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Which instrument control affects the amplitude (dB) of the outgoing signal:
Which instrument control affects the amplitude (dB) of the outgoing signal:
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Which of the following is used to convert Doppler shift information into color:
Which of the following is used to convert Doppler shift information into color:
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Pulse repetition frequency is the:
Pulse repetition frequency is the:
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The best way to increase the near field length of an ultrasound beam is to:
The best way to increase the near field length of an ultrasound beam is to:
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The range of frequencies produced by a damped PZT element is called:
The range of frequencies produced by a damped PZT element is called:
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The percentage of time that the ultrasound instrument is emitting ultrasound is called:
The percentage of time that the ultrasound instrument is emitting ultrasound is called:
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The unit of duty factor is:
The unit of duty factor is:
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Quality Factor equals:
Quality Factor equals:
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Clinical imaging transducers are:
Clinical imaging transducers are:
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Power/area equals:
Power/area equals:
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Increasing wavelength will __________ frequency.
Increasing wavelength will __________ frequency.
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All of the following directly affect frame rate except:
All of the following directly affect frame rate except:
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A reflection will occur at the boundary of two media if the acoustic impedances of the two media are:
A reflection will occur at the boundary of two media if the acoustic impedances of the two media are:
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A mechanical transducer utilizes:
A mechanical transducer utilizes:
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The transducer frequency is primarily determined by the transducer element:
The transducer frequency is primarily determined by the transducer element:
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A strongly focused transducer implies a:
A strongly focused transducer implies a:
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B-mode displays reflector:
B-mode displays reflector:
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An increase in the number of pixels on the display will improve:
An increase in the number of pixels on the display will improve:
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Propagation speed is determined by:
Propagation speed is determined by:
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Increasing transmit gain increases everything except:
Increasing transmit gain increases everything except:
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The correct depth placement of reflectors depends primarily upon:
The correct depth placement of reflectors depends primarily upon:
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Which of the following will increase the color flow jet area displayed?
Which of the following will increase the color flow jet area displayed?
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Increasing propagation speed:
Increasing propagation speed:
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The most common type of transducer used in echo is:
The most common type of transducer used in echo is:
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Decibels are the units for all of the following except:
Decibels are the units for all of the following except:
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What are the four acoustic variables:
What are the four acoustic variables:
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Frequency is:
Frequency is:
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Pulse duration is:
Pulse duration is:
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Wavelength is:
Wavelength is:
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An increase in packet size will ______ the frame rate:
An increase in packet size will ______ the frame rate:
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The range for audible sound is:
The range for audible sound is:
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The wavelength of a 1 MHz transducer is:
The wavelength of a 1 MHz transducer is:
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The average speed of sound in soft tissue is:
The average speed of sound in soft tissue is:
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An increase in overall gain will result in all of the following except:
An increase in overall gain will result in all of the following except:
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Reject eliminates:
Reject eliminates:
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There have been no proven biological effects for unfocused transducers for intensities below:
There have been no proven biological effects for unfocused transducers for intensities below:
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The primary cause of attenuation of ultrasound in soft tissue is caused by:
The primary cause of attenuation of ultrasound in soft tissue is caused by:
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Resolution artifact occurs when:
Resolution artifact occurs when:
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Damping does not decrease:
Damping does not decrease:
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Spectral broadening is:
Spectral broadening is:
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Refraction is:
Refraction is:
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Autocorrelation is used to:
Autocorrelation is used to:
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PRF stands for:
PRF stands for:
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Period is:
Period is:
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How do you decrease period?
How do you decrease period?
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Impedance is:
Impedance is:
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The unit for impedance is:
The unit for impedance is:
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Study Notes
Exam Preparation for ARDMS SPI
- Bioeffects Risk: Increasing transmit gain heightens the risk of bioeffects during ultrasound procedures.
Ultrasound Instrumentation
- Memory Component: The digital scan converter acts as the memory unit in an ultrasound instrument.
Flow Characteristics
- Spectral Broadening: Indicates the presence of turbulent flow rather than laminar flow.
Imaging Fundamentals
- Pulse Wave Doppler: Axial resolution degrades with pulse wave Doppler imaging.
- Color Flow Doppler: Turbulent flow is typically indicated by the color green in Doppler variance mapping.
Doppler Filters
- High Pass Filter: The Doppler wall filter functions as a high pass filter to eliminate low-velocity flow and high amplitude signals.
Key Doppler Principles
- Nyquist Limit: Determined using the formula PRF/2, this frequency limit is essential for Doppler measurements.
- Doppler Shift: Increases with higher red blood cell velocities; the velocity scale is critical for accurate color flow mapping.
Transducer Insights
- Ultrasound Frequency: Frequency primarily depends on the thickness of the transducer element, while the range for clinical imaging generally falls between 2 MHz and 10 MHz.
- Focused Transducer: A strongly focused transducer features a short focal length which contributes to increased beam divergence.
Imaging Quality Factors
- Resolution: Improvement in image detail resolution correlates with an increase in the number of pixels displayed.
Acoustic Properties
- Sound Propagation Speed: Primarily defined by the medium's bulk modulus, with soft tissue having an average speed of 1540 m/s.
- Wavelength Calculation: Wavelength is calculated as propagation speed divided by frequency. For a 1 MHz transducer, the wavelength is 1.54 mm.
Frame Rate and Artifacts
- Factors Affecting Frame Rate: Depth of penetration, field of view, number of focuses, and line density all impact frame rate, whereas beam width does not.
- Resolution Artifact: Occurs when two parallel structures are perceived as one, affecting imaging clarity.
Attenuation and Power
- Principle of Attenuation: Absorption in soft tissue is the primary cause of ultrasound attenuation.
- Gain Adjustments: Overall gain increase raises image brightness and signal amplification but does not increase output power.
Other Relevant Concepts
- Duty Factor: Represents the percentage of time the ultrasound instrument emits sound; it is unitless and can range from 0 to 1.
- Acoustic Variables: Include temperature, density, particle motion, and pressure, which critically affect ultrasound transmission and reception.
Fundamental Concepts Recap
- Period and Frequency Relationships: Period is the time per cycle and inversely relates to frequency (1/frequency).
- Impedance: Defined as the opposition to sound propagation, measured in Rayls.
Conclusion on Safety
- Biological Effects: No proven effects have been noted for unfocused transducers below an intensity of 100 mW/cm² (SPTA).
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Description
Prepare for the ARDMS Physics SPI exam with these flashcards. Each card highlights key terminology and concepts essential for success. Enhance your understanding of ultrasound instrumentation and workflow with quick recall questions.
