ARDMS SPI Exam Flashcards
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Questions and Answers

Which gain will increase the risk of bioeffects?

  • Receive
  • Gain
  • Overall Gain
  • Transmit (correct)

Which of the following is considered the memory of an ultrasound instrument?

  • Display Monitor
  • Transducer
  • Digital Scan Converter (correct)
  • Pulser
  • Receiver
  • Beam Former

Spectral broadening suggests:

  • Turbulent Flow (correct)
  • Flow Away from the Transducer
  • Laminar Flow
  • Flow Towards the Transducer

With pulse wave Doppler, axial resolution:

<p>degrades</p> Signup and view all the answers

What color is usually used in color flow Doppler variance maps to indicate turbulent flow?

<p>green</p> Signup and view all the answers

Doppler high pass filter eliminates:

<p>high amplitude signals; low velocity flow</p> Signup and view all the answers

The Doppler wall filter is considered a:

<p>high pass filter</p> Signup and view all the answers

The Nyquist Limit is equal to:

<p>PRF / 2 (D)</p> Signup and view all the answers

Multiple echoes, equally spaced originating from a gas bubble is called:

<p>Ring Down (D)</p> Signup and view all the answers

An increase in red blood cell velocity will _____ the Doppler Shift:

<p>Increase (A)</p> Signup and view all the answers

The primary advantage of CW Doppler is:

<p>Absence of Sampling Rate (B)</p> Signup and view all the answers

The range for ultrasound begins:

<p>20,000 Hz (B)</p> Signup and view all the answers

Which instrument control affects the amplitude (dB) of the outgoing signal:

<p>Transmit Gain (A)</p> Signup and view all the answers

Which of the following is used to convert Doppler shift information into color:

<p>Autocorrelation (B)</p> Signup and view all the answers

Pulse repetition frequency is the:

<p>number of pulses that an ultrasound system transmits into the body each second.</p> Signup and view all the answers

The best way to increase the near field length of an ultrasound beam is to:

<p>increase transducer diameter</p> Signup and view all the answers

The range of frequencies produced by a damped PZT element is called:

<p>Bandwidth (A)</p> Signup and view all the answers

The percentage of time that the ultrasound instrument is emitting ultrasound is called:

<p>Duty Factor (B)</p> Signup and view all the answers

The unit of duty factor is:

<p>Unitless (D)</p> Signup and view all the answers

Quality Factor equals:

<p>Fundamental Frequency / Bandwidth</p> Signup and view all the answers

Clinical imaging transducers are:

<p>wide bandwidth; low Q factor</p> Signup and view all the answers

Power/area equals:

<p>Intensity</p> Signup and view all the answers

Increasing wavelength will __________ frequency.

<p>Decrease (A)</p> Signup and view all the answers

All of the following directly affect frame rate except:

<p>Beam Width (C)</p> Signup and view all the answers

A reflection will occur at the boundary of two media if the acoustic impedances of the two media are:

<p>Different (B)</p> Signup and view all the answers

A mechanical transducer utilizes:

<p>Fixed Focus (D)</p> Signup and view all the answers

The transducer frequency is primarily determined by the transducer element:

<p>Thickness (B)</p> Signup and view all the answers

A strongly focused transducer implies a:

<p>Short Focal Length; Increased Beam Divergence (C)</p> Signup and view all the answers

B-mode displays reflector:

<p>Amplitude and Distance (C)</p> Signup and view all the answers

An increase in the number of pixels on the display will improve:

<p>detail resolution</p> Signup and view all the answers

Propagation speed is determined by:

<p>Bulk Modulus (B)</p> Signup and view all the answers

Increasing transmit gain increases everything except:

<p>frequency</p> Signup and view all the answers

The correct depth placement of reflectors depends primarily upon:

<p>Propagation Speed (B)</p> Signup and view all the answers

Which of the following will increase the color flow jet area displayed?

<p>Increase Color Gain (B)</p> Signup and view all the answers

Increasing propagation speed:

<p>air, soft tissue, bone</p> Signup and view all the answers

The most common type of transducer used in echo is:

<p>sector phased array</p> Signup and view all the answers

Decibels are the units for all of the following except:

<p>Intensity (G)</p> Signup and view all the answers

What are the four acoustic variables:

<p>temperature, density, particle motion, pressure</p> Signup and view all the answers

Frequency is:

<p>cycles per second (Hz)</p> Signup and view all the answers

Pulse duration is:

<p>period (ms) x number of cycles in a pulse</p> Signup and view all the answers

Wavelength is:

<p>the length of one cycle</p> Signup and view all the answers

An increase in packet size will ______ the frame rate:

<p>decrease</p> Signup and view all the answers

The range for audible sound is:

<p>20 Hz - 20 kHz</p> Signup and view all the answers

The wavelength of a 1 MHz transducer is:

<p>1.54 mm</p> Signup and view all the answers

The average speed of sound in soft tissue is:

<p>1540 m/s, 1.54 km/s, 1.54 mm/μs</p> Signup and view all the answers

An increase in overall gain will result in all of the following except:

<p>Increase in Output Power (D)</p> Signup and view all the answers

Reject eliminates:

<p>low amplitude signals</p> Signup and view all the answers

There have been no proven biological effects for unfocused transducers for intensities below:

<p>100 mW/cm^2 SPTA</p> Signup and view all the answers

The primary cause of attenuation of ultrasound in soft tissue is caused by:

<p>absorption</p> Signup and view all the answers

Resolution artifact occurs when:

<p>two structures parallel to the ultrasound beam are displayed as one reflector.</p> Signup and view all the answers

Damping does not decrease:

<p>bandwidth</p> Signup and view all the answers

Spectral broadening is:

<p>the widening of the Doppler shift spectrum.</p> Signup and view all the answers

Refraction is:

<p>the change in direction of a wave when it changes speed as it travels from one material to another.</p> Signup and view all the answers

Autocorrelation is used to:

<p>convert Doppler shift information into color.</p> Signup and view all the answers

PRF stands for:

<p>Pulse Repetition Frequency.</p> Signup and view all the answers

Period is:

<p>the time per cycle</p> Signup and view all the answers

How do you decrease period?

<p>increase frequency</p> Signup and view all the answers

Impedance is:

<p>the opposition of sound propagation</p> Signup and view all the answers

The unit for impedance is:

<p>Rayls</p> Signup and view all the answers

Flashcards

Bioeffects Risk

Risk of harmful effects during ultrasound caused by increasing transmit gain.

Digital Scan Converter

The memory unit in an ultrasound instrument responsible for digitizing images.

Spectral Broadening

Indicates turbulent flow rather than smooth or laminar flow in blood vessels.

Axial Resolution

The ability to distinguish two structures along the axis of the ultrasound beam.

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Color Flow Doppler

Ultrasound technique that uses color to visualize blood flow, where green indicates turbulence.

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High Pass Filter

Eliminates low-velocity flow and high amplitude signals in Doppler imaging.

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Nyquist Limit

The maximum measurable frequency in Doppler ultrasound, determined by PRF/2.

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Doppler Shift

Change in frequency caused by motion of red blood cells, crucial for accurate mapping.

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Ultrasound Frequency

Determined by the transducer element's thickness, typically between 2-10 MHz for clinical use.

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Focused Transducer

Has a short focal length, leading to greater beam divergence.

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Resolution

Improvement in image clarity linked to an increase in pixel count.

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Sound Propagation Speed

Speed at which sound travels in a medium, defined by bulk modulus.

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Wavelength Calculation

Wavelength is derived from propagation speed divided by frequency, e.g., 1.54 mm at 1 MHz.

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Factors Affecting Frame Rate

Includes depth, field of view, number of focuses, and line density.

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Resolution Artifact

Occurs when two parallel structures appear as one, reducing image clarity.

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Principle of Attenuation

Absorption in soft tissue is the primary cause of ultrasound signal loss.

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Gain Adjustments

Increasing gain boosts image brightness but does not enhance output power.

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Duty Factor

Percentage of time the ultrasound instrument sends out sound; unitless, ranges from 0 to 1.

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Acoustic Variables

Properties affecting ultrasound, including temperature, density, particle motion, and pressure.

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Period

Time taken for one cycle of sound; inversely related to frequency.

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Impedance

Opposition to sound propagation, measured in Rayls.

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Biological Effects

No proven harmful effects for unfocused transducers below 100 mW/cm² intensity.

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Turbulent Flow

A chaotic flow pattern in blood vessels, typically detected in Doppler imaging.

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Gain

Adjustable control increasing the amplitude of the ultrasound signal.

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Beam Divergence

The spreading of the ultrasound beam as it travels away from the transducer.

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Clinical Imaging Range

Typical frequency range for clinical ultrasound imaging between 2 MHz and 10 MHz.

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Pulse Wave Doppler

Doppler ultrasound technique where sampling occurs at discrete intervals.

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Color Doppler Variance Mapping

Technique that uses color variance to show blood flow direction and turbulence.

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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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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.

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