ARDMS SPI MCQ 2 — Questions and Answers
Question 1: Which effect describes the heating of tissue caused by the absorption of ultrasound energy?
- Piezoelectric effect
- Thermal bioeffect (Correct answer)
- Cavitation
- Doppler shift
Correct answer: Thermal bioeffect
Thermal bioeffects occur when absorbed ultrasound energy is converted to heat within tissue.
Question 2: What does a higher Q-factor in a transducer indicate?
- Broader bandwidth and better axial resolution
- Narrower bandwidth and longer pulse duration (Correct answer)
- Faster pulse repetition frequency
- Greater depth penetration
Correct answer: Narrower bandwidth and longer pulse duration
A high Q-factor transducer has a narrow bandwidth and produces a longer, less damped pulse.
Question 3: In pulsed wave Doppler, aliasing occurs when the Doppler shift frequency exceeds:
- The center frequency of the transducer
- One-half the pulse repetition frequency (Nyquist limit) (Correct answer)
- The wall filter setting
- The frame rate
Correct answer: One-half the pulse repetition frequency (Nyquist limit)
Aliasing occurs when the detected Doppler shift exceeds the Nyquist limit, which is half the PRF.
Question 4: Which artifact appears as multiple equally spaced reflectors beyond a highly reflective structure?
- Shadowing
- Comet tail
- Reverberation (Correct answer)
- Refraction
Correct answer: Reverberation
Reverberation artifact creates multiple equally spaced echoes as sound bounces repeatedly between two reflectors.
Question 5: The speed of sound in soft tissue is approximately:
- 331 m/s
- 1540 m/s (Correct answer)
- 3500 m/s
- 760 m/s
Correct answer: 1540 m/s
The assumed speed of sound in soft tissue used by diagnostic ultrasound systems is approximately 1540 m/s.
Question 6: What is the primary advantage of spatial compounding in ultrasound imaging?
- Increased frame rate
- Reduced speckle and improved contrast resolution (Correct answer)
- Greater depth penetration
- Narrower pulse width
Correct answer: Reduced speckle and improved contrast resolution
Spatial compounding averages images acquired from multiple steering angles, reducing speckle and improving contrast resolution.
Question 7: Which transducer type uses a rotating or wobbling mechanical element to sweep the beam?
- Linear array
- Phased array
- Mechanical transducer (Correct answer)
- Annular array
Correct answer: Mechanical transducer
Mechanical transducers use a physically moving element to sweep the ultrasound beam across the imaging plane.
ARDMS SPI MCQ 2
Which effect describes the heating of tissue caused by the absorption of ultrasound energy?