ARDMS SPI EXAM LATEST QUESTIONS AND 120-
Verified ANSWERS.
TABLE OF CONTENTS
Section Questions Topic Domain
Section 1 1–20 Sound Waves and Propagation
Section 2 21–40 Transducers and Beam Formation
Section 3 41–60 Pulse-Echo Instrumentation
Section 4 61–80 Doppler Principles and Hemodynamics
Section 5 81–95 Artifacts
Section 6 96–110 Quality Assurance, Bioeffects, and Safety
Section 7 111–120 Image Optimization and Advanced Technology
SECTION 1: SOUND WAVES AND PROPAGATION (Questions 1–20)
1. What is the average speed of sound in human soft tissue?
• A) 1,450 m/s
• B) 1,540 m/s
• C) 1,600 m/s
, • D) 4,800 m/s
Rationale: 1,540 m/s is the standard propagation speed used by ultrasound
systems to calculate depth and distance in soft tissue. This value is assumed by all
diagnostic ultrasound equipment for accurate image formation.
2. Frequency is defined as:
• A) The number of cycles per second
• B) The time for one cycle to occur
• C) The distance of one cycle
• D) The rate of energy transfer
Rationale: Frequency (measured in Hertz) represents how many complete cycles
occur in one second. It is determined by the transducer's piezoelectric crystal and
cannot be changed by the operator.
3. Wavelength is calculated by:
• A) Speed ÷ Frequency
• B) Frequency ÷ Speed
• C) Speed × Frequency
• D) 2 × Frequency
Rationale: Wavelength (λ) equals propagation speed (c) divided by frequency (f).
This inverse relationship means higher frequency = shorter wavelength = better
axial resolution.
4. Which of the following acoustic variables is NOT required for sound
propagation?
• A) Pressure
• B) Density
• C) Particle motion
, • D) Temperature
Rationale: The three acoustic variables are pressure, density, and particle motion.
Temperature is not an acoustic variable required for sound wave propagation.
5. A transducer with a frequency of 10 MHz produces sound waves in soft tissue.
What is the approximate wavelength?
• A) 0.15 mm
• B) 0.154 mm
• C) 1.54 mm
• D) 15.4 mm
Rationale: Using the formula Wavelength = Speed ÷ Frequency = 1,540 m/s ÷
10,000,000 Hz = 0.000154 m = 0.154 mm.
6. Axial resolution is primarily determined by:
• A) Beam width
• B) Spatial pulse length
• C) Frame rate
• D) Dynamic range
Rationale: Axial resolution (ability to distinguish two structures along the beam's
axis) is determined by spatial pulse length. Shorter pulses improve axial resolution.
7. Which statement about propagation speed is TRUE?
• A) Speed increases with tissue density
• B) Speed is constant regardless of the medium
• C) Speed is determined by the medium's stiffness and density
• D) Speed decreases with increasing stiffness
, Rationale: Propagation speed is determined by the bulk modulus (stiffness) and
density of the medium. Sound travels faster in stiffer media and slower in denser
media.
8. The attenuation of ultrasound in soft tissue is approximately:
• A) 1 dB/cm/MHz
• B) 0.5 dB/cm/MHz
• C) 2 dB/cm/MHz
• D) 3 dB/cm/MHz
Rationale: Attenuation in soft tissue is approximately 1 dB for each centimeter of
depth per MHz of frequency. This relationship helps determine appropriate
transducer selection.
9. Which component contributes MOST to attenuation in soft tissue?
• A) Absorption
• B) Reflection
• C) Scattering
• D) Refraction
Rationale: Absorption is the primary mechanism of attenuation in soft tissue,
converting sound energy to heat. Reflection and scattering also contribute but to a
lesser degree.
10. A shorter wavelength will result in:
• A) Better axial resolution and less penetration
• B) Better axial resolution and better penetration
• C) Worse axial resolution and less penetration
• D) Worse axial resolution and better penetration
Verified ANSWERS.
TABLE OF CONTENTS
Section Questions Topic Domain
Section 1 1–20 Sound Waves and Propagation
Section 2 21–40 Transducers and Beam Formation
Section 3 41–60 Pulse-Echo Instrumentation
Section 4 61–80 Doppler Principles and Hemodynamics
Section 5 81–95 Artifacts
Section 6 96–110 Quality Assurance, Bioeffects, and Safety
Section 7 111–120 Image Optimization and Advanced Technology
SECTION 1: SOUND WAVES AND PROPAGATION (Questions 1–20)
1. What is the average speed of sound in human soft tissue?
• A) 1,450 m/s
• B) 1,540 m/s
• C) 1,600 m/s
, • D) 4,800 m/s
Rationale: 1,540 m/s is the standard propagation speed used by ultrasound
systems to calculate depth and distance in soft tissue. This value is assumed by all
diagnostic ultrasound equipment for accurate image formation.
2. Frequency is defined as:
• A) The number of cycles per second
• B) The time for one cycle to occur
• C) The distance of one cycle
• D) The rate of energy transfer
Rationale: Frequency (measured in Hertz) represents how many complete cycles
occur in one second. It is determined by the transducer's piezoelectric crystal and
cannot be changed by the operator.
3. Wavelength is calculated by:
• A) Speed ÷ Frequency
• B) Frequency ÷ Speed
• C) Speed × Frequency
• D) 2 × Frequency
Rationale: Wavelength (λ) equals propagation speed (c) divided by frequency (f).
This inverse relationship means higher frequency = shorter wavelength = better
axial resolution.
4. Which of the following acoustic variables is NOT required for sound
propagation?
• A) Pressure
• B) Density
• C) Particle motion
, • D) Temperature
Rationale: The three acoustic variables are pressure, density, and particle motion.
Temperature is not an acoustic variable required for sound wave propagation.
5. A transducer with a frequency of 10 MHz produces sound waves in soft tissue.
What is the approximate wavelength?
• A) 0.15 mm
• B) 0.154 mm
• C) 1.54 mm
• D) 15.4 mm
Rationale: Using the formula Wavelength = Speed ÷ Frequency = 1,540 m/s ÷
10,000,000 Hz = 0.000154 m = 0.154 mm.
6. Axial resolution is primarily determined by:
• A) Beam width
• B) Spatial pulse length
• C) Frame rate
• D) Dynamic range
Rationale: Axial resolution (ability to distinguish two structures along the beam's
axis) is determined by spatial pulse length. Shorter pulses improve axial resolution.
7. Which statement about propagation speed is TRUE?
• A) Speed increases with tissue density
• B) Speed is constant regardless of the medium
• C) Speed is determined by the medium's stiffness and density
• D) Speed decreases with increasing stiffness
, Rationale: Propagation speed is determined by the bulk modulus (stiffness) and
density of the medium. Sound travels faster in stiffer media and slower in denser
media.
8. The attenuation of ultrasound in soft tissue is approximately:
• A) 1 dB/cm/MHz
• B) 0.5 dB/cm/MHz
• C) 2 dB/cm/MHz
• D) 3 dB/cm/MHz
Rationale: Attenuation in soft tissue is approximately 1 dB for each centimeter of
depth per MHz of frequency. This relationship helps determine appropriate
transducer selection.
9. Which component contributes MOST to attenuation in soft tissue?
• A) Absorption
• B) Reflection
• C) Scattering
• D) Refraction
Rationale: Absorption is the primary mechanism of attenuation in soft tissue,
converting sound energy to heat. Reflection and scattering also contribute but to a
lesser degree.
10. A shorter wavelength will result in:
• A) Better axial resolution and less penetration
• B) Better axial resolution and better penetration
• C) Worse axial resolution and less penetration
• D) Worse axial resolution and better penetration
