Free ARDMS SPI Practice Exam with Questions & Answers

Comprehensive and Detailed Explanation From Exact Extract:

Persistence is a post-processing technique that averages multiple consecutive image frames to reduce random noise and improve image smoothness. This is especially useful for reducing speckle and enhancing the clarity of stationary or slow-moving structures.

According to official sonography Principles and Instrumentation documentation:

"Persistence uses frame averaging, combining data from several sequential frames to reduce noise, enhance image quality, and stabilize the appearance of stationary structures."

Demodulation (A) is part of signal processing that extracts the Doppler frequency shift.

Compression (C) alters the dynamic range of the image but does not reduce noise through frame averaging.

Time gain compensation (D) adjusts amplification at various depths to equalize brightness but does not perform frame averaging.

Therefore, the correct answer is B: Persistence.

QUESTION NO12

What does this image demonstrate?

A ultrasound of a fetus Description automatically generated

A. Presence of flow

B. Direction of flow

C. Color aliasing

D. Color inversion

Answer: C

Comprehensive and Detailed Explanation From Exact Extract:

In the provided image, the color Doppler display shows a mixture of colors (typically red, yellow, and shades shifting abruptly), indicating that velocities have exceeded the Nyquist limit — the maximum detectable Doppler shift for the given pulse repetition frequency (PRF). This creates a color aliasing artifact.

According to the official sonography Principles and Instrumentation documentation:

"Color aliasing occurs when flow velocities exceed the Nyquist limit, causing a wrap-around of the color scale. This results in abrupt changes in color hue that do not accurately represent flow direction or velocity."

Presence of flow (A) is correct but too general.

Direction of flow (B) refers to color assignment but not to the artifact seen.

Color inversion (D) inverts the color map but does not cause the abrupt color changes seen here.

The alternating, banded colors are classic for color aliasing, confirming that the correct answer is C: Color aliasing.

The resonant frequency of a pulsed wave transducer is determined by the thickness of the piezoelectric element and the speed of sound within that element. The resonant frequency is inversely proportional to the element thickness and directly proportional to the speed of sound in the material. Thinner elements and higher sound speeds result in higher resonant frequencies, while thicker elements and lower sound speeds result in lower resonant frequencies.

ARDMS Sonography Principles and Instrumentation guidelines

Kremkau, F. W. (2015). Diagnostic Ultrasound: Principles and Instruments. Elsevier.

Comprehensive and Detailed Explanation From Exact Extract:

Slice thickness (elevational resolution artifact) occurs when the ultrasound beam partially includes surrounding tissue above or below the scan plane, falsely appearing as internal echoes within an otherwise anechoic cyst.

Principles and Instrumentation:

"Slice thickness artifact occurs when off-axis echoes are included in the imaging slice, falsely creating internal echoes in cystic structures."

Refraction (A) causes displacement.

Enhancement (B) causes posterior brightening.

Range ambiguity (D) produces incorrect depth placement.

Therefore, the correct answer is C: Slice thickness.

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Incorrect color Doppler gain settings can cause the artifact known as bleed or blossoming. When the color Doppler gain is set too high, it can cause the color signal to "bleed" outside the actual boundaries of the blood vessel, leading to an overestimation of the area of flow. This artifact makes it appear as though the blood flow extends beyond the true vessel walls, which can obscure the accurate interpretation of the Doppler image.

References

ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide

"Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau

Comprehensive and Detailed Explanation From Exact Extract:

When the ultrasound beam travels through a structure that attenuates less than surrounding tissues, more energy reaches structures located deeper. This results in stronger echo signals from those deeper structures, which is visualized as a brightening or enhancement distal to the structure. This is referred to as acoustic enhancement or posterior enhancement.

Official sonography instrumentation reference states:

“Enhancement occurs as a result of reduced attenuation of the sound beam as it passes through fluid-filled or weakly attenuating structures, causing reflectors distal to the structure to appear more echogenic than normal.”

Therefore, the correct answer is B: Enhancement.

Comprehensive and Detailed Explanation From Exact Extract:

Output power directly affects the intensity of the ultrasound beam transmitted into the patient. Reducing output power lowers the risk of both thermal and mechanical bioeffects.

According to sonography instrumentation reference:

“Output power should be minimized following the ALARA (As Low As Reasonably Achievable) principle to reduce potential bioeffects while still obtaining diagnostic-quality images.”

Therefore, the correct answer is B: Output power.

78

In this image, which characteristics of flow are represented by the upper right side of a variance mode color map?

A close-up of a screen Description automatically generated

A. Higher velocity, laminar with a positive Doppler shift

B. Higher velocity, laminar with a negative Doppler shift

C. Higher velocity, turbulent with a positive Doppler shift

D. Higher velocity, turbulent with a negative Doppler shift

Answer: C

Comprehensive and Detailed Explanation From Exact Extract:

In variance mode color Doppler, colors are assigned based on both flow direction (Doppler shift polarity) and flow character (laminar vs turbulent). In the image:

The vertical color bar shows standard Doppler shifts: positive shifts (toward the transducer) are displayed at the top, and negative shifts (away from the transducer) at the bottom.

The variance mode adds horizontal color variation (from left to right), where the right side indicates increasing turbulence.

Thus, the upper right portion of the color bar indicates:

Positive Doppler shift (flow toward the transducer)

High velocity

Turbulent flow

According to sonography instrumentation reference:

“In variance mode, the vertical axis represents flow direction and velocity, while the horizontal axis represents flow variance (turbulence). The upper right corner indicates high-velocity turbulent flow toward the transducer.”

Therefore, the correct answer is C: Higher velocity, turbulent with a positive Doppler shift.

Comprehensive and Detailed Explanation From Exact Extract:

Axial resolution is determined by the spatial pulse length (SPL). A longer SPL means that structures closer together along the beam axis are more likely to overlap in the returning echoes, degrading axial resolution.

According to sonography instrumentation reference:

“Axial resolution is inversely related to spatial pulse length. Increasing SPL worsens the ability to distinguish closely spaced structures along the beam axis.”

Therefore, the correct answer is B: Degraded axial resolution.

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86

Based on the table in this image, what is the sensitivity?

A white square with black numbers and a white square with black numbers Description automatically generated

A. 32/33

B. 32/35

C. 45/46

D. 45/48

Answer: B

Comprehensive and Detailed Explanation From Exact Extract:

Sensitivity measures the test's ability to correctly identify true positives. It is calculated using the formula:

Sensitivity = True Positives / (True Positives + False Negatives)

From the table:

True Positives (TP) = 32 (Noninvasive test positive & Gold Standard positive)

False Negatives (FN) = 3 (Noninvasive test negative but Gold Standard positive)

Thus:

Sensitivity = 32 / (32 + 3)

Sensitivity = 32 / 35

According to sonography instrumentation reference:

“Sensitivity represents the proportion of actual positive cases correctly identified by the test.”

Therefore, the correct answer is B: 32/35.

At what Doppler angle to flow is the maximum Doppler shift frequency acquired?

A. 90 degrees

B. 60 degrees

C. 30 degrees

D. 0 degrees

Answer: D

Comprehensive and Detailed Explanation From Exact Extract:

The Doppler equation shows that the frequency shift is proportional to the cosine of the Doppler angle. The maximum value of cosine (cos 0° = 1) occurs at 0 degrees — meaning the beam is parallel to flow. At this angle, the full velocity component is measured.

According to sonography instrumentation reference:

“The maximum Doppler shift is obtained when the ultrasound beam is parallel (0 degrees) to blood flow.”

Therefore, the correct answer is D: 0 degrees.

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Comprehensive and Detailed Explanation From Exact Extract:

A larger sample volume collects Doppler signals from a wider region, which can include multiple velocities and noise. This leads to a broader spectrum (spectral broadening) and may introduce additional noise into the signal.

According to sonography instrumentation reference:

“Increasing the sample volume size increases the likelihood of including multiple velocity components and noise, resulting in spectral broadening and reduced spectral clarity.”

Therefore, the correct answer is B: Increased noise.

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Comprehensive and Detailed Explanation From Exact Extract:

A tissue-mimicking phantom contains small targets at known separations to evaluate the system’s axial resolution, lateral resolution, depth calibration, and more.

Principles and Instrumentation state:

"Tissue-mimicking phantoms assess spatial resolution (axial, lateral), depth accuracy, and penetration performance."

Hydrophones (B) measure acoustic pressure.

Beam profilers (C) assess beam characteristics.

Doppler phantoms (D) test Doppler function.

Therefore, the correct answer is A: Tissue-mimicking phantom.

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When the depth of imaging is increased, the time it takes for the ultrasound pulses to travel to and from the deeper structures also increases, which can reduce the frame rate. To maintain the same frame rate, one effective adjustment is to decrease the image width. Narrowing the image width reduces the number of scan lines required to create each frame, allowing the system to maintain a higher frame rate despite the increased depth.

ARDMS Sonography Principles and Instrumentation guidelines

Kremkau, F. W. (2015). Diagnostic Ultrasound: Principles and Instruments.