ARDMS SPI EXAM (2025 LATEST VERSION) -
SIMULATED PRACTICE EXAM
ALL QUESTIONS AND CORRECT ANSWERS
(GRADED A+) | VERIFIED ANSWERS
Instructions: This exam simulates the content and format of the ARDMS SPI
examination. For each question, select the single best answer based on sonography
principles and instrumentation.
[Section 1: Clinical Safety & Physical Principles - Questions 1-20]
1. According to the ALARA principle, which of the following is the PRIMARY
responsibility of the sonographer?
A. To use the highest possible frequency transducer for all studies.
B. To use the lowest possible transmitted acoustic energy to obtain diagnostic
images.
C. To minimize exam time, regardless of output power.
D. To always use harmonic imaging to reduce bioeffects.
Correct Answer: B
Verification & Rationale: ALARA (As Low As Reasonably Achievable) mandates
minimizing acoustic exposure while maintaining diagnostic quality. Option B is
the only choice that balances patient safety with image adequacy. High power (A)
violates ALARA; time (C) is only one factor; harmonic imaging (D) is technique-
specific, not the overarching principle (SPI Outline 1A; Edelman, 5th ed., Ch. 2).
2. The intensity (I) of an ultrasound beam is defined as:
A. Power per unit area (W/cm²).
B. Energy per unit time (J/s).
C. Amplitude squared (MPa²).
D. Frequency multiplied by wavelength (Hz·m).
Correct Answer: A
Verification & Rationale: I = P/A is the fundamental definition of intensity.
Amplitude squared relates to pressure intensity, not beam intensity; J/s is power;
f·λ = propagation speed (SPI Outline 1B).
3. Which tissue interface produces the greatest acoustic impedance mismatch?
A. Liver–kidney
B. Muscle–fat
C. Soft tissue–lung
D. Blood–myocardium
Correct Answer: C
Verification & Rationale: Impedance Z = ρc. Lung has very low ρ (≈0.4 kg/m³) vs.
pg. 1
, soft tissue (≈1000 kg/m³), giving a >99 % reflection coefficient (Edelman, Ch. 3,
Table 3-2).
4. The half-value layer (HVL) for 3 MHz ultrasound in soft tissue is approximately:
A. 0.5 cm
B. 1 cm
C. 2 cm
D. 4 cm
Correct Answer: C
Verification & Rationale: HVL ≈ 2 cm at 3 MHz (attenuation coefficient ≈ 0.5
dB/cm·MHz × 3 MHz → 1.5 dB/cm; 3 dB ≈ 2 cm).
5. Which artifact is MOST likely to be reduced by lowering the transmit power?
A. Reverberation
B. Speed displacement
C. Acoustic shadowing
D. Enhancement
Correct Answer: A
Verification & Rationale: Reverberation is a multiple-reflection artifact whose
amplitude scales with transmit power; reducing power lowers subsequent
echoes (SPI Outline 3D).
6. The mechanical index (MI) is calculated as:
A. Peak rarefactional pressure ÷ √frequency.
B. SPTA intensity × frequency.
C. PRF × duty factor.
D. Wavelength ÷ pulse duration.
Correct Answer: A
Verification & Rationale: MI = pr/√f (FDA 510(k) guidance); relates to cavitation
risk.
7. Which of the following is a bio-effect associated with cavitation?
A. Thermal necrosis
B. Microbubble oscillation and collapse
C. Shear-stress hemolysis
D. Radiation force displacement
Correct Answer: B
Verification & Rationale: Cavitation is the formation/collapse of gas bubbles;
thermal effects (A) are temperature-based; shear (C) and radiation force (D) are
non-cavitational (AIUM Bioeffects Primer).
8. The temperature rise considered potentially hazardous in fetal scanning is:
A. >0.5 °C
B. >1.0 °C
C. >2.0 °C
pg. 2
, D. >6.0 °C
Correct Answer: B
Verification & Rationale: FDA & AIUM recommend TIs ≤1.0 for fetal scans; >1 °C
may affect fetal neurodevelopment (AIUM Statement 2024).
9. Which scan plane is associated with the LOWEST ocular exposure during first-
trimester endovaginal imaging?
A. Sagittal uterus
B. Coronal uterus
C. Oblique cervix
D. Endometrial lining only
Correct Answer: B
Verification & Rationale: Coronal plane places the beam perpendicular to the
orbital axis, maximizing distance and attenuation, minimizing ocular exposure.
10. The Thermal Index for bone (TIB) is MOST relevant when scanning:
A. First-trimester fetus
B. Adult abdominal aorta
C. Neonatal hip
D. Thyroid in a 30-year-old
Correct Answer: C
Verification & Rationale: TIB applies when bone is at or near the focus (neonatal
hip has ossified femoral head).
11. Which action BEST reduces the risk of a transducer-surface heating artifact?
A. Increase frame rate
B. Use a stand-off pad
C. Activate harmonic imaging
D. Increase focal depth
Correct Answer: B
Verification & Rationale: Stand-off pads increase distance, allowing tissue cooling
and reducing conductive heating from the transducer face.
12. The speed of sound in soft tissue is closest to:
A. 1,200 m/s
B. 1,540 m/s
C. 1,800 m/s
D. 3,000 m/s
Correct Answer: B
Verification & Rationale: Accepted average is 1,540 m/s (1.54 mm/µs) at 37 °C
(SPI Outline 1B).
13. Which frequency exhibits the GREATEST attenuation in soft tissue?
A. 2 MHz
B. 5 MHz
pg. 3
SIMULATED PRACTICE EXAM
ALL QUESTIONS AND CORRECT ANSWERS
(GRADED A+) | VERIFIED ANSWERS
Instructions: This exam simulates the content and format of the ARDMS SPI
examination. For each question, select the single best answer based on sonography
principles and instrumentation.
[Section 1: Clinical Safety & Physical Principles - Questions 1-20]
1. According to the ALARA principle, which of the following is the PRIMARY
responsibility of the sonographer?
A. To use the highest possible frequency transducer for all studies.
B. To use the lowest possible transmitted acoustic energy to obtain diagnostic
images.
C. To minimize exam time, regardless of output power.
D. To always use harmonic imaging to reduce bioeffects.
Correct Answer: B
Verification & Rationale: ALARA (As Low As Reasonably Achievable) mandates
minimizing acoustic exposure while maintaining diagnostic quality. Option B is
the only choice that balances patient safety with image adequacy. High power (A)
violates ALARA; time (C) is only one factor; harmonic imaging (D) is technique-
specific, not the overarching principle (SPI Outline 1A; Edelman, 5th ed., Ch. 2).
2. The intensity (I) of an ultrasound beam is defined as:
A. Power per unit area (W/cm²).
B. Energy per unit time (J/s).
C. Amplitude squared (MPa²).
D. Frequency multiplied by wavelength (Hz·m).
Correct Answer: A
Verification & Rationale: I = P/A is the fundamental definition of intensity.
Amplitude squared relates to pressure intensity, not beam intensity; J/s is power;
f·λ = propagation speed (SPI Outline 1B).
3. Which tissue interface produces the greatest acoustic impedance mismatch?
A. Liver–kidney
B. Muscle–fat
C. Soft tissue–lung
D. Blood–myocardium
Correct Answer: C
Verification & Rationale: Impedance Z = ρc. Lung has very low ρ (≈0.4 kg/m³) vs.
pg. 1
, soft tissue (≈1000 kg/m³), giving a >99 % reflection coefficient (Edelman, Ch. 3,
Table 3-2).
4. The half-value layer (HVL) for 3 MHz ultrasound in soft tissue is approximately:
A. 0.5 cm
B. 1 cm
C. 2 cm
D. 4 cm
Correct Answer: C
Verification & Rationale: HVL ≈ 2 cm at 3 MHz (attenuation coefficient ≈ 0.5
dB/cm·MHz × 3 MHz → 1.5 dB/cm; 3 dB ≈ 2 cm).
5. Which artifact is MOST likely to be reduced by lowering the transmit power?
A. Reverberation
B. Speed displacement
C. Acoustic shadowing
D. Enhancement
Correct Answer: A
Verification & Rationale: Reverberation is a multiple-reflection artifact whose
amplitude scales with transmit power; reducing power lowers subsequent
echoes (SPI Outline 3D).
6. The mechanical index (MI) is calculated as:
A. Peak rarefactional pressure ÷ √frequency.
B. SPTA intensity × frequency.
C. PRF × duty factor.
D. Wavelength ÷ pulse duration.
Correct Answer: A
Verification & Rationale: MI = pr/√f (FDA 510(k) guidance); relates to cavitation
risk.
7. Which of the following is a bio-effect associated with cavitation?
A. Thermal necrosis
B. Microbubble oscillation and collapse
C. Shear-stress hemolysis
D. Radiation force displacement
Correct Answer: B
Verification & Rationale: Cavitation is the formation/collapse of gas bubbles;
thermal effects (A) are temperature-based; shear (C) and radiation force (D) are
non-cavitational (AIUM Bioeffects Primer).
8. The temperature rise considered potentially hazardous in fetal scanning is:
A. >0.5 °C
B. >1.0 °C
C. >2.0 °C
pg. 2
, D. >6.0 °C
Correct Answer: B
Verification & Rationale: FDA & AIUM recommend TIs ≤1.0 for fetal scans; >1 °C
may affect fetal neurodevelopment (AIUM Statement 2024).
9. Which scan plane is associated with the LOWEST ocular exposure during first-
trimester endovaginal imaging?
A. Sagittal uterus
B. Coronal uterus
C. Oblique cervix
D. Endometrial lining only
Correct Answer: B
Verification & Rationale: Coronal plane places the beam perpendicular to the
orbital axis, maximizing distance and attenuation, minimizing ocular exposure.
10. The Thermal Index for bone (TIB) is MOST relevant when scanning:
A. First-trimester fetus
B. Adult abdominal aorta
C. Neonatal hip
D. Thyroid in a 30-year-old
Correct Answer: C
Verification & Rationale: TIB applies when bone is at or near the focus (neonatal
hip has ossified femoral head).
11. Which action BEST reduces the risk of a transducer-surface heating artifact?
A. Increase frame rate
B. Use a stand-off pad
C. Activate harmonic imaging
D. Increase focal depth
Correct Answer: B
Verification & Rationale: Stand-off pads increase distance, allowing tissue cooling
and reducing conductive heating from the transducer face.
12. The speed of sound in soft tissue is closest to:
A. 1,200 m/s
B. 1,540 m/s
C. 1,800 m/s
D. 3,000 m/s
Correct Answer: B
Verification & Rationale: Accepted average is 1,540 m/s (1.54 mm/µs) at 37 °C
(SPI Outline 1B).
13. Which frequency exhibits the GREATEST attenuation in soft tissue?
A. 2 MHz
B. 5 MHz
pg. 3
