SPI ARDMS Test A and B | Questions and
Answers Plus Rationale | New 2026-2027 Update
1. What is dynamic aperture?
• A. Aperture that varies with transmit frequency
• B. Aperture that decreases as a function of time
• C. Aperture that increases with increasing focal length
• D. Aperture that changes as a function of frame rate
Correct Answer: C — Aperture that increases with increasing focal length
Rationale: Dynamic aperture uses a variable number of active elements to
optimize beam width at different depths. As focal length increases, the aperture
increases to maintain a narrow beam at the focus.
2. To which acoustic variable is penetration depth inversely related?
• A. Frequency
• B. Wavelength
• C. Period
• D. Propagation speed
Correct Answer: A — Frequency
Rationale: Higher frequency increases attenuation in tissue, so penetration
decreases. Lower frequency penetrates deeper.
3. Which imaging mode requires a broadband transducer?
• A. Continuous wave Doppler
, • B. Pulsed wave Doppler
• C. Color flow imaging
• D. Harmonic imaging
Correct Answer: B — Pulsed wave Doppler
Rationale: Pulsed wave Doppler requires short pulses with a broad range of
frequencies to provide range resolution and Doppler information.
4. What is the Doppler shift frequency?
• A. Received ultrasound frequency multiplied by the transmitted ultrasound
frequency
• B. Difference between the transmitted ultrasound frequency and the
received ultrasound frequency
• C. Sum of the transmitted and received ultrasound frequencies
• D. Ratio of the transmitted ultrasound frequency to the received ultrasound
frequency
Correct Answer: B — Difference between the transmitted ultrasound frequency
and the received ultrasound frequency
Rationale: Doppler shift is the change in frequency caused by motion of the
reflector relative to the transducer: received frequency minus transmitted
frequency.
5. What is the potential effect of increasing the pulse repetition frequency
(PRF)?
• A. Depth ambiguity
• B. Decreased frame rate
• C. Poor spatial resolution
• D. Decreased penetration
,Correct Answer: A — Depth ambiguity
Rationale: Increasing PRF shortens the pulse repetition period, reducing the
maximum depth that can be unambiguously resolved. This can cause range
ambiguity (depth ambiguity). Note: The source marked D, but the correct physics
answer is A.
6. What is an advantage of using pulsed wave Doppler compared to continuous
wave Doppler?
• A. Higher echo sensitivity
• B. Ability to select sample depth
• C. Decreased display of aliasing
• D. Improved temporal resolution
Correct Answer: B — Ability to select sample depth
Rationale: Pulsed wave Doppler uses range gating to select a specific sample
volume depth, which continuous wave Doppler cannot do.
7. What affects the beam width in the near field?
• A. Pulse repetition frequency
• B. Pulse duration
• C. Frame rate
• D. Transducer aperture
Correct Answer: D — Transducer aperture
Rationale: Near-field beam width is determined primarily by the transducer
aperture (diameter) and frequency. Larger aperture produces a narrower beam in
the near field.
, 8. What is the advantage of using pulsed-wave Doppler versus continuous-wave
Doppler?
• A. Allows measurement of higher velocities
• B. Increases range ambiguity
• C. Reduces the potential for aliasing
• D. Provides depth specificity
Correct Answer: D — Provides depth specificity
Rationale: Pulsed-wave Doppler provides depth specificity through range gating.
Continuous-wave Doppler lacks depth resolution.
9. Which parameter is target group C evaluating based on the image?
• A. Dead zone
• B. Dynamic range
• C. Axial resolution
• D. Horizontal distance accuracy
Correct Answer: D — Horizontal distance accuracy
Rationale: Target group C in phantom testing typically evaluates horizontal
distance accuracy by measuring known horizontal distances between reflectors.
10. What parameter is target group A evaluating based on the image?
Image-dependent question; no options provided in source.
• A. Axial resolution
• B. Lateral resolution
• C. Dead zone
• D. Sensitivity
Answers Plus Rationale | New 2026-2027 Update
1. What is dynamic aperture?
• A. Aperture that varies with transmit frequency
• B. Aperture that decreases as a function of time
• C. Aperture that increases with increasing focal length
• D. Aperture that changes as a function of frame rate
Correct Answer: C — Aperture that increases with increasing focal length
Rationale: Dynamic aperture uses a variable number of active elements to
optimize beam width at different depths. As focal length increases, the aperture
increases to maintain a narrow beam at the focus.
2. To which acoustic variable is penetration depth inversely related?
• A. Frequency
• B. Wavelength
• C. Period
• D. Propagation speed
Correct Answer: A — Frequency
Rationale: Higher frequency increases attenuation in tissue, so penetration
decreases. Lower frequency penetrates deeper.
3. Which imaging mode requires a broadband transducer?
• A. Continuous wave Doppler
, • B. Pulsed wave Doppler
• C. Color flow imaging
• D. Harmonic imaging
Correct Answer: B — Pulsed wave Doppler
Rationale: Pulsed wave Doppler requires short pulses with a broad range of
frequencies to provide range resolution and Doppler information.
4. What is the Doppler shift frequency?
• A. Received ultrasound frequency multiplied by the transmitted ultrasound
frequency
• B. Difference between the transmitted ultrasound frequency and the
received ultrasound frequency
• C. Sum of the transmitted and received ultrasound frequencies
• D. Ratio of the transmitted ultrasound frequency to the received ultrasound
frequency
Correct Answer: B — Difference between the transmitted ultrasound frequency
and the received ultrasound frequency
Rationale: Doppler shift is the change in frequency caused by motion of the
reflector relative to the transducer: received frequency minus transmitted
frequency.
5. What is the potential effect of increasing the pulse repetition frequency
(PRF)?
• A. Depth ambiguity
• B. Decreased frame rate
• C. Poor spatial resolution
• D. Decreased penetration
,Correct Answer: A — Depth ambiguity
Rationale: Increasing PRF shortens the pulse repetition period, reducing the
maximum depth that can be unambiguously resolved. This can cause range
ambiguity (depth ambiguity). Note: The source marked D, but the correct physics
answer is A.
6. What is an advantage of using pulsed wave Doppler compared to continuous
wave Doppler?
• A. Higher echo sensitivity
• B. Ability to select sample depth
• C. Decreased display of aliasing
• D. Improved temporal resolution
Correct Answer: B — Ability to select sample depth
Rationale: Pulsed wave Doppler uses range gating to select a specific sample
volume depth, which continuous wave Doppler cannot do.
7. What affects the beam width in the near field?
• A. Pulse repetition frequency
• B. Pulse duration
• C. Frame rate
• D. Transducer aperture
Correct Answer: D — Transducer aperture
Rationale: Near-field beam width is determined primarily by the transducer
aperture (diameter) and frequency. Larger aperture produces a narrower beam in
the near field.
, 8. What is the advantage of using pulsed-wave Doppler versus continuous-wave
Doppler?
• A. Allows measurement of higher velocities
• B. Increases range ambiguity
• C. Reduces the potential for aliasing
• D. Provides depth specificity
Correct Answer: D — Provides depth specificity
Rationale: Pulsed-wave Doppler provides depth specificity through range gating.
Continuous-wave Doppler lacks depth resolution.
9. Which parameter is target group C evaluating based on the image?
• A. Dead zone
• B. Dynamic range
• C. Axial resolution
• D. Horizontal distance accuracy
Correct Answer: D — Horizontal distance accuracy
Rationale: Target group C in phantom testing typically evaluates horizontal
distance accuracy by measuring known horizontal distances between reflectors.
10. What parameter is target group A evaluating based on the image?
Image-dependent question; no options provided in source.
• A. Axial resolution
• B. Lateral resolution
• C. Dead zone
• D. Sensitivity
