100+ Free SPI Practice Questions

Pass your ARDMS Sonography Principles and Instrumentation exam on the first try — instant access, no signup required.

✓ No registration✓ No credit card✓ No hidden fees✓ Start practicing immediately

100+ Questions

100% Free

1 / 100

Question 1

Score: 0/0

The dead zone in QA testing refers to:

The deepest visible target

The slice thickness near the focus

The blind sector behind a strong reflector

The shallow region near the transducer where targets cannot be resolved

to track

Same family resources

More ARDMS Certifications Prep

Continue through related practice pages, study guides, comparisons, and articles from the same exam family.

Practice Pages

ARDMS Adult Echocardiography (RDCS) Practice200 questions ARDMS OB/GYN (RDMS) Practice200 questions ARDMS Pediatric Echocardiography (RDCS) Practice200 questions ARDMS Vascular Technology (RVT) Practice200 questions ARDMS Abdomen (RDMS) Practice199 questions ARDMS Fetal Echocardiography (RDCS) Practice198 questions

FREE ARDMS RDCS Adult Echo Exam Guide 2026: Pass the AE32 min read FREE ARDMS RDCS Pediatric Echo Exam Guide 2026 (PE)34 min read FREE ARDMS RDMS Abdomen (AB) Exam Guide 2026: Pass on First Try33 min read FREE ARDMS RVT Exam Guide 2026: Vascular Technology Pass Plan28 min read

2026 Statistics

Key Facts: SPI Exam

~110

Total Items

ARDMS

2 hrs

Exam Time

ARDMS

$275

Exam Fee

ARDMS

555/700

Passing Scaled Score

ARDMS

5 yrs

Window for SPI + Specialty

Both must be passed within 5 years

ARDMS SPI is the REQUIRED physics prerequisite for all RDMS, RDCS, RVT, RMSKS specialty credentials. ~110 MCQ items, 2 hours, $275 fee, scaled passing 555/700. Must pass SPI + specialty within 5 years. Master Doppler equation, Nyquist limit (PRF/2), range equation, axial vs lateral resolution, transducer construction, ALARA principle with TI/MI thermal/mechanical indices, and the six core artifacts (reverberation, mirror, comet tail, shadowing/enhancement, refraction, aliasing).

Sample SPI Practice Questions

Try these sample questions to test your SPI exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1What is the average propagation speed of ultrasound in soft tissue?

A.330 m/s

B.1540 m/s

C.4080 m/s

D.1480 m/s

Explanation: The assumed average propagation speed of ultrasound in soft tissue is 1540 m/s (1.54 mm/μs). This value is used by all clinical scanners to calculate depth from echo arrival time.

2Ultrasound waves used in diagnostic imaging are best classified as what type of mechanical wave?

A.Transverse waves

B.Longitudinal waves

C.Electromagnetic waves

D.Standing waves

Explanation: Diagnostic ultrasound consists of longitudinal waves, where particle motion is parallel to the direction of wave propagation, creating compressions and rarefactions in the medium.

3If frequency doubles in soft tissue, what happens to wavelength?

A.Doubles

B.Quadruples

C.Halves

D.Stays the same

Explanation: Wavelength λ = c/f. Since speed is constant in soft tissue, doubling the frequency halves the wavelength. Higher frequency means shorter wavelength.

4What is the wavelength of a 5 MHz ultrasound beam in soft tissue?

A.0.154 mm

B.0.308 mm

C.0.77 mm

D.3.08 mm

Explanation: λ = c/f = 1.54 mm/μs ÷ 5 MHz = 0.308 mm. A simple shortcut: wavelength in mm equals 1.54 divided by frequency in MHz.

5Which acoustic variable describes the concentration of energy in a beam?

A.Pressure

B.Density

C.Intensity

D.Temperature

Explanation: Intensity is the rate of energy transfer per unit area (W/cm²) and represents the concentration of acoustic energy in a beam. Intensity is proportional to the square of pressure amplitude.

6If pressure amplitude is doubled, by what factor does intensity change?

A.Doubles

B.Triples

C.Quadruples

D.Halves

Explanation: Intensity is proportional to pressure amplitude squared (I ∝ P²). Doubling the pressure quadruples the intensity (2² = 4).

7Acoustic impedance is the product of which two properties?

A.Frequency and wavelength

B.Density and propagation speed

C.Pressure and intensity

D.Power and area

Explanation: Acoustic impedance Z = ρc, the product of medium density (ρ) and propagation speed (c). The unit is the rayl. Differences in impedance at interfaces produce reflections.

8What is the typical attenuation coefficient in soft tissue?

A.0.1 dB/cm/MHz

B.0.5 dB/cm/MHz

C.1.5 dB/cm/MHz

D.5 dB/cm/MHz

Explanation: The standard attenuation coefficient in soft tissue is 0.5 dB/cm/MHz. Total attenuation in dB equals 0.5 × frequency (MHz) × path length (cm).

9A 4 MHz beam travels 6 cm one-way through soft tissue. What is the total one-way attenuation?

A.6 dB

B.12 dB

C.24 dB

D.3 dB

Explanation: Attenuation = 0.5 dB/cm/MHz × 4 MHz × 6 cm = 12 dB one-way. This is why higher frequencies cannot penetrate as deeply as lower frequencies.

10Which is the largest contributor to attenuation in soft tissue?

A.Reflection

B.Refraction

C.Absorption

D.Diffraction

Explanation: Absorption (conversion of acoustic energy to heat) is the dominant cause of attenuation in soft tissue. Scattering and reflection contribute much less.

About the SPI Exam

ARDMS Sonography Principles and Instrumentation — REQUIRED physics prerequisite for ALL ARDMS specialty credentials (RDMS Abdomen/OB-GYN/Breast/Pediatric, RDCS Adult/Pediatric/Fetal, RVT, RMSKS). Must pass SPI + specialty within 5 years for full credential. Validates expertise in ultrasound physics (wave propagation, attenuation, range equation), transducer construction and beam, pulse-echo instrumentation (TGC, dynamic range, postprocessing), Doppler principles (PW, CW, color, power), QA/bioeffects/safety (ALARA, MI, TI), and artifact recognition.

Questions

110 scored questions

Time Limit

2 hours

Passing Score

Scaled 555/700

Exam Fee

$275 (ARDMS)

SPI Exam Content Outline

25%

Ultrasound Physics (Wave, Propagation, Interactions)

λ=c/f, Z=ρc, attenuation 0.5 dB/cm/MHz, reflection, range equation

20%

Transducers (Construction, Beam, Resolution)

PZT crystal, matching layer, types (linear, curvilinear, phased, endocavitary), axial/lateral/elevational resolution

20%

Pulse-Echo Instrumentation

TGC, dynamic range, compression, scan converter, postprocessing

20%

Doppler Principles

Doppler equation, angle 60° rule, Nyquist limit, PW vs CW vs color vs power

10%

QA, Bioeffects, Safety

ALARA, TI (TIB/TIC/TIS), MI, prudent use; obstetric scanning

Artifacts

Reverberation, mirror, comet tail, shadowing/enhancement, refraction, aliasing

How to Pass the SPI Exam

What You Need to Know

Passing score: Scaled 555/700
Exam length: 110 questions
Time limit: 2 hours
Exam fee: $275

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

SPI Study Tips from Top Performers

1Master core formulas: speed of sound 1540 m/s; λ = c/f; Doppler Δf = 2f×v×cos θ/c; Nyquist = PRF/2

2Memorize axial resolution = SPL/2 (improved with shorter pulse, higher frequency); lateral = beam width

3Know angle correction rule: ≤60° for accurate Doppler; 90° gives no shift

4Understand TI (Thermal Index — TIB/TIC/TIS) and MI (Mechanical Index — cavitation risk); ALARA principle

5Recognize key artifacts: reverberation (parallel reflectors), mirror (highly reflective surface), comet tail (gas), shadowing (acoustic), enhancement (fluid), aliasing (Nyquist violated)

Frequently Asked Questions

Why is SPI required for all ARDMS specialty exams?

ARDMS requires SPI as a separate physics prerequisite to ensure all sonographers — regardless of clinical specialty — have a foundational understanding of ultrasound physics, instrumentation, and safety. Candidates must pass SPI + their specialty exam (e.g., AB, OB/GYN, RVT, RMSKS, BR, PS) within 5 years to receive the full credential. SPI alone does not grant a clinical credential.

What is the Doppler equation?

Doppler frequency shift Δf = (2 × f₀ × v × cos θ) / c, where f₀ = transmitted frequency, v = blood velocity, θ = angle between sound beam and flow vector, c = speed of sound (1540 m/s in soft tissue). Angle correction: 60° is the maximum acceptable angle (cos 60° = 0.5; smaller angle gives higher accuracy). Angle 90° gives no Doppler shift (cos 90° = 0).

What is the Nyquist limit?

Nyquist limit = PRF/2 — the maximum Doppler frequency shift PW Doppler can accurately measure without aliasing. If the Doppler frequency exceeds Nyquist, aliasing occurs (color wraps around or spectral wraps to the other side of baseline). Solutions for aliasing: increase PRF (raise scale), lower transmit frequency, increase angle (closer to 90°), shift baseline, or switch to CW Doppler (no aliasing because CW has no PRF).

How should I study for SPI?

Plan 40-60 hours over 6-8 weeks. Focus on Ultrasound Physics (25%), Transducers (20%), Pulse-Echo (20%), and Doppler (20%) — together 85% of exam. Master core formulas: λ = c/f, range equation depth = c×t/2, Doppler equation, axial resolution = SPL/2, NZL = D²/(4λ). Understand the artifacts and their causes.