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Free SPI Practice Questions

10 free, exam-style Sonography Principles and Instrumentation (SPI) (SPI) practice questions with answers and explanations. No signup required. Work through them below, then take the full free SPI practice test to study every exam domain.

The SPI exam has 110 questions and runs 2 hours.

These 10 free SPI questions are organized by exam domain, so you can see how each part of the Sonography Principles and Instrumentation (SPI) blueprint is tested. Reveal the answer and explanation under each question.

Domain 1: Perform Ultrasound Examinations 23% of exam

Question 1

While scanning, a sonographer switches from a 9 MHz to a 3 MHz transducer. With respect to the propagation speed of sound through the patient's soft tissue, this change will:

  1. Have no effect, because propagation speed is set by the medium
  2. Decrease the propagation speed, because lower-frequency sound is known to travel more slowly through tissue
  3. Increase the propagation speed, because lower frequencies penetrate more deeply and therefore move faster
  4. Decrease the propagation speed in direct proportion to the increase in wavelength that occurs
Show answer & explanation

Correct answer: A - Have no effect, because propagation speed is set by the medium

Question 2

Posterior to a simple, fluid-filled cyst, the sonographer observes a column of increased echo brightness compared with the surrounding tissue at the same depth. This finding is BEST described as:

  1. Acoustic enhancement caused by low attenuation through the cyst
  2. Acoustic shadowing caused by strong attenuation within the cyst
  3. A mirror-image artifact created by the posterior cyst wall
  4. Refraction (edge) shadowing arising at the lateral cyst borders
Show answer & explanation

Correct answer: A - Acoustic enhancement caused by low attenuation through the cyst

Domain 2: Manage Ultrasound Transducers 7% of exam

Question 3

Increasing the amount of damping (backing material) behind the active element of a transducer will:

  1. Lengthen the spatial pulse length and improve penetration
  2. Narrow the bandwidth and raise the Q-factor of the transducer
  3. Shorten the spatial pulse length and improve axial resolution
  4. Increase the resonant frequency at which the element operates
Show answer & explanation

Correct answer: C - Shorten the spatial pulse length and improve axial resolution

Domain 3: Optimize Sonographic Images 26% of exam

Question 4

A sonographer wants to improve axial resolution while scanning a superficial structure. Which change will accomplish this?

  1. Widening the imaging sector so that additional scan lines are included in the frame
  2. Decreasing spatial pulse length with a higher-frequency probe
  3. Moving the transmit focal zone well below the structure of interest
  4. Increasing the overall receiver gain in order to brighten the returning echoes
Show answer & explanation

Correct answer: B - Decreasing spatial pulse length with a higher-frequency probe

Question 5

A sonographer adjusts the time gain compensation (TGC) sliders so the image is uniformly bright from near field to far field. Regarding acoustic output and patient exposure, this adjustment:

  1. Increases acoustic output in the far field to overcome tissue attenuation
  2. Does not change acoustic output; TGC only amplifies returning echoes
  3. Decreases acoustic output within the near field to prevent overexposure
  4. Raises both the mechanical and the thermal index displayed on screen
Show answer & explanation

Correct answer: B - Does not change acoustic output; TGC only amplifies returning echoes

Domain 4: Apply Doppler Concepts 34% of exam

Question 6

A sonographer images a patent carotid artery with the beam oriented perpendicular (90°) to the direction of blood flow. Despite obvious vessel patency on gray-scale, the spectral display shows essentially no Doppler signal. The MOST likely explanation is:

  1. The wall filter is set too high and is rejecting the flow signal
  2. The vessel must be occluded, and gray-scale patency is artifactual
  3. At a 90° angle the cosine of the Doppler angle equals zero, so virtually no frequency shift is generated or detected
  4. The pulse repetition frequency is set too high for this depth
Show answer & explanation

Correct answer: C - At a 90° angle the cosine of the Doppler angle equals zero, so virtually no frequency shift is generated or detected

Question 7

Compared with color Doppler, power (energy) Doppler is characterized by which of the following?

  1. It encodes the mean velocity of flow within each color pixel
  2. It is more prone to aliasing because it relies on a higher PRF
  3. It displays the direction of flow but cannot show velocity
  4. It is more sensitive to slow flow and is largely angle-independent, but provides no information about flow direction
Show answer & explanation

Correct answer: D - It is more sensitive to slow flow and is largely angle-independent, but provides no information about flow direction

Question 8

A vascular sonographer needs to localize the exact depth of a velocity measurement within a vessel. Which statement correctly contrasts pulsed-wave (PW) and continuous-wave (CW) Doppler?

  1. CW provides depth resolution, whereas PW samples the entire beam path
  2. Both PW and CW provide range resolution, but only CW can alias
  3. PW and CW are interchangeable for depth-specific velocity sampling
  4. PW provides range (depth) resolution but is subject to aliasing
Show answer & explanation

Correct answer: D - PW provides range (depth) resolution but is subject to aliasing

Question 9

A pulsed-wave Doppler examination is being performed with a pulse repetition frequency (PRF) of 8 kHz. The Nyquist limit for this setting is:

  1. 4 kHz
  2. 2 kHz
  3. 8 kHz
  4. 16 kHz
Show answer & explanation

Correct answer: A - 4 kHz

Domain 5: Provide Clinical Safety & Quality Assurance 10% of exam

Question 10

A sonographer is performing a contrast-enhanced study using microbubble contrast agent. To preserve the microbubbles and optimize the contrast signal, the mechanical index (MI) should be:

  1. Raised above 1.0 to maximize the returning echo amplitude
  2. Kept low, typically below an MI of about 0.3, so that the fragile microbubbles are not prematurely destroyed
  3. Set to the FDA maximum of 1.9 for the strongest signal
  4. Matched to the thermal index so both indices read the same value
Show answer & explanation

Correct answer: B - Kept low, typically below an MI of about 0.3, so that the fragile microbubbles are not prematurely destroyed

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