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:

degrades Signup and view all the answers

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

green Signup and view all the answers

Doppler high pass filter eliminates:

high amplitude signals; low velocity flow Signup and view all the answers

The Doppler wall filter is considered a:

high pass filter Signup and view all the answers

The Nyquist Limit is equal to:

PRF / 2 Signup and view all the answers

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

Ring Down Signup and view all the answers

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

Increase Signup and view all the answers

The primary advantage of CW Doppler is:

Absence of Sampling Rate Signup and view all the answers

The range for ultrasound begins:

20,000 Hz Signup and view all the answers

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

Transmit Gain Signup and view all the answers

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

Autocorrelation Signup and view all the answers

Pulse repetition frequency is the:

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

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

increase transducer diameter Signup and view all the answers

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

Bandwidth Signup and view all the answers

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

Duty Factor Signup and view all the answers

The unit of duty factor is:

Unitless Signup and view all the answers

Quality Factor equals:

Fundamental Frequency / Bandwidth Signup and view all the answers

Clinical imaging transducers are:

wide bandwidth; low Q factor Signup and view all the answers

Power/area equals:

Intensity Signup and view all the answers

Increasing wavelength will __________ frequency.

Decrease Signup and view all the answers

All of the following directly affect frame rate except:

Beam Width 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:

Different Signup and view all the answers

A mechanical transducer utilizes:

Fixed Focus Signup and view all the answers

The transducer frequency is primarily determined by the transducer element:

Thickness Signup and view all the answers

A strongly focused transducer implies a:

Short Focal Length; Increased Beam Divergence Signup and view all the answers

B-mode displays reflector:

Amplitude and Distance Signup and view all the answers

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

detail resolution Signup and view all the answers

Propagation speed is determined by:

Bulk Modulus Signup and view all the answers

Increasing transmit gain increases everything except:

frequency Signup and view all the answers

The correct depth placement of reflectors depends primarily upon:

Propagation Speed Signup and view all the answers

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

Increase Color Gain Signup and view all the answers

Increasing propagation speed:

air, soft tissue, bone Signup and view all the answers

The most common type of transducer used in echo is:

sector phased array Signup and view all the answers

Decibels are the units for all of the following except:

Intensity Signup and view all the answers

What are the four acoustic variables:

temperature, density, particle motion, pressure Signup and view all the answers

Frequency is:

cycles per second (Hz) Signup and view all the answers

Pulse duration is:

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

Wavelength is:

the length of one cycle Signup and view all the answers

An increase in packet size will ______ the frame rate:

decrease Signup and view all the answers

The range for audible sound is:

20 Hz - 20 kHz Signup and view all the answers

The wavelength of a 1 MHz transducer is:

1.54 mm Signup and view all the answers

The average speed of sound in soft tissue is:

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

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

Increase in Output Power Signup and view all the answers

Reject eliminates:

low amplitude signals Signup and view all the answers

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

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

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

absorption Signup and view all the answers

Resolution artifact occurs when:

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

Damping does not decrease:

bandwidth Signup and view all the answers

Spectral broadening is:

the widening of the Doppler shift spectrum. Signup and view all the answers

Refraction is:

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

Autocorrelation is used to:

convert Doppler shift information into color. Signup and view all the answers

PRF stands for:

Pulse Repetition Frequency. Signup and view all the answers

Period is:

the time per cycle Signup and view all the answers

How do you decrease period?

increase frequency Signup and view all the answers

Impedance is:

the opposition of sound propagation Signup and view all the answers

The unit for impedance is:

Rayls Signup and view all the answers

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.