ARDMS SPI Cheat Sheet 2026

The 30 highest-yield ARDMS SPI facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. The average propagation speed of sound in soft tissue used by ultrasound systems is: → 1540 m/s
2. Which acoustic parameter is determined solely by the medium through which sound travels? → Propagation speed
3. Which formula correctly relates the attenuation in dB for soft tissue? → Attenuation (dB) ≈ 0.5 × frequency (MHz) × depth (cm)
4. A high-resistance spectral Doppler waveform is characterized by: → Low or absent end-diastolic velocity with a sharp systolic peak
5. What happens to the visual display when a mechanical transducer's PZT crystal is damaged? → Loss of entire image
6. Which effect describes the heating of tissue caused by the absorption of ultrasound energy? → Thermal bioeffect
7. Attenuation of ultrasound in soft tissue is approximately: → 0.5 dB/cm/MHz
8. Laminar flow in a vessel is characterized by: → Concentric layers of blood moving at different velocities with fastest flow centrally
9. Which tissue type has the highest attenuation coefficient at a given frequency? → Bone
10. Which statement correctly compares axial and lateral resolution at a specific depth? → Axial resolution is typically better than lateral resolution
11. Harmonic imaging reduces which type of artifact compared to fundamental imaging? → Near-field clutter and side lobe artifacts
12. On color Doppler, a vessel showing reversed color assignment relative to the adjacent artery in the same image most likely indicates: → Venous flow direction opposite to arterial flow
13. Which color Doppler parameter directly controls the number of pulses used to estimate each color pixel? → Ensemble length (packet size)
14. What artifact is produced when refraction causes the beam to miss its intended target? → Lateral displacement artifact
15. Which artifact causes a color Doppler signal to appear on the opposite side of a strong reflector at the same depth? → Mirror image artifact
16. What does a higher Q-factor in a transducer indicate? → Narrower bandwidth and longer pulse duration
17. What is the primary purpose of the matching layer in a transducer? → Reduce acoustic impedance mismatch between crystal and tissue
18. The Pulsatility Index (PI) is calculated as: → (PSV - EDV) / TAMV
19. Which structure absorbs the most ultrasound energy per unit length and therefore poses the greatest risk of localized heating? → Cortical bone
20. Which aperture change improves lateral resolution for a linear array? → Increasing the active aperture
21. Which parameter does NOT directly affect axial resolution? → Active aperture width
22. What is the primary purpose of adjusting the focal zone position on an ultrasound system? → To maximize lateral resolution at a specific depth
23. Which transducer performance defect is most likely to produce a focal band of absent or reduced echoes at a specific depth in a QA phantom image? → A dead row of elements in a 1.5D array
24. Which transducer type provides the SMALLEST footprint and is therefore best suited for cardiac imaging between rib spaces? → Phased array
25. What is the primary reason ultrasound QA records should be kept for a minimum of several years? → To document trending of performance changes and support accreditation reviews
26. The Doppler equation states that the Doppler shift is directly proportional to which of the following? → The transmitted frequency, flow velocity, and cosine of the Doppler angle
27. Which transducer design characteristic MOST directly determines axial resolution? → Spatial pulse length
28. When the color Doppler gate is positioned at 90° to flow direction, the resulting color display will show: → No color signal
29. Frame rate in real-time ultrasound is most directly limited by: → The speed of sound and imaging depth
30. What is the purpose of time-gain compensation (TGC) in ultrasound imaging? → To amplify echoes from deeper structures to compensate for attenuation