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.
ARDMS SPI Ultrasound System Controls and Knobology 2
Dynamic range in ultrasound imaging refers to the ratio of which two signal values?