ARDMS SPI Ultrasound System Controls and Knobology 2 — Questions and Answers
Question 1: Dynamic range in ultrasound imaging refers to the ratio of which two signal values?
- Highest to lowest detectable echo amplitude (Correct answer)
- Transmit frequency to receive frequency
- Near field length to far field length
- Maximum depth to minimum depth
Correct answer: Highest to lowest detectable echo amplitude
Dynamic range is the ratio of the largest to the smallest signal amplitude the system can display, measured in decibels.
Question 2: Harmonic imaging reduces which type of artifact compared to fundamental imaging?
- Shadowing
- Enhancement
- Near-field clutter and side lobe artifacts (Correct answer)
- Comet tail artifact
Correct answer: Near-field clutter and side lobe artifacts
Tissue harmonic imaging uses the second harmonic frequency generated within tissue, which reduces near-field clutter and side lobe artifacts.
Question 3: The ensemble length (packet size) in color Doppler refers to:
- The number of pulses per scan line used to produce color information (Correct answer)
- The width of the color box
- The frequency of the color transmit pulse
- The number of color frames averaged per second
Correct answer: The number of pulses per scan line used to produce color information
Ensemble length is the number of pulses fired along each color Doppler scan line; larger ensemble lengths improve velocity accuracy but reduce frame rate.
Question 4: What is the primary effect of increasing transmit frequency on image quality?
- Improved penetration but worse resolution
- Improved resolution but reduced penetration (Correct answer)
- No change in resolution or penetration
- Improved both resolution and penetration equally
Correct answer: Improved resolution but reduced penetration
Higher frequencies produce shorter wavelengths, improving spatial resolution, but are attenuated more rapidly, reducing depth penetration.
Question 5: Which setting would a sonographer adjust to reduce aliasing in pulsed wave Doppler without switching to CW Doppler?
- Decrease wall filter
- Increase PRF (Correct answer)
- Decrease overall gain
- Increase ensemble length
Correct answer: Increase PRF
Increasing PRF raises the Nyquist limit, allowing higher velocities to be measured before aliasing occurs.
Question 6: Spatial compounding averages frames acquired from multiple steering angles primarily to:
- Increase frame rate
- Reduce speckle and improve tissue boundary definition (Correct answer)
- Increase penetration depth
- Eliminate all shadowing artifacts
Correct answer: Reduce speckle and improve tissue boundary definition
Spatial compounding averages overlapping frames from different angles, reducing speckle noise and improving contrast resolution at tissue interfaces.