SPI Practice (ARDMS A & B) Questions and
Correct Answer plus Rationale | Latest 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 refers to the number of active elements in an array
changing with depth/focal length. As focal length increases, more elements are
used to maintain resolution.
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, reducing penetration depth.
Therefore, penetration depth is inversely related to frequency.
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, which require broadband
transducers.
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 difference between transmitted and received
frequencies.
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 pulse repetition period, which can cause depth
ambiguity because echoes from deeper structures may arrive after the next pulse
is sent.
, 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 has range resolution/sample volume selection,
allowing depth specificity.
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: Beam width in the near field is determined by transducer aperture
(diameter) and frequency.
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 (range resolution);
continuous wave does not.
Correct Answer plus Rationale | Latest 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 refers to the number of active elements in an array
changing with depth/focal length. As focal length increases, more elements are
used to maintain resolution.
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, reducing penetration depth.
Therefore, penetration depth is inversely related to frequency.
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, which require broadband
transducers.
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 difference between transmitted and received
frequencies.
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 pulse repetition period, which can cause depth
ambiguity because echoes from deeper structures may arrive after the next pulse
is sent.
, 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 has range resolution/sample volume selection,
allowing depth specificity.
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: Beam width in the near field is determined by transducer aperture
(diameter) and frequency.
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 (range resolution);
continuous wave does not.
