ARDMS SPI Quality Assurance and Phantoms 4 — Questions and Answers
Question 1: What AIUM-recommended QA frequency is typically suggested for clinical ultrasound equipment used daily?
- Annual testing only
- Weekly or monthly performance testing with documented records (Correct answer)
- Testing only when a clinical complaint arises
- Testing every two years during accreditation renewal
Correct answer: Weekly or monthly performance testing with documented records
The AIUM recommends regular (weekly to monthly) QA testing with documented records to detect and trend performance changes before they affect clinical outcomes.
Question 2: In ultrasound QA, what is the significance of measuring the -6 dB beam width at the focal zone?
- It determines the maximum allowable acoustic output
- It quantifies lateral resolution at the focal depth (Correct answer)
- It establishes the pulse repetition frequency
- It measures the axial pulse length
Correct answer: It quantifies lateral resolution at the focal depth
The -6 dB beam width at the focal zone corresponds to the minimum lateral separation at which two point targets can be resolved, directly defining lateral resolution.
Question 3: A sonographer compares current QA phantom images to baseline and notes reduced image brightness at depth despite unchanged gain settings. What is the most likely cause?
- The phantom has been stored too cold
- Transducer sensitivity has decreased due to element degradation (Correct answer)
- The monitor brightness has increased
- The PRF was inadvertently lowered
Correct answer: Transducer sensitivity has decreased due to element degradation
Decreased transducer sensitivity from element aging or damage reduces the amplitude of returning echoes, manifesting as reduced brightness at depth.
Question 4: Which of the following phantom measurements is most useful for evaluating the effectiveness of harmonic imaging compared to fundamental imaging?
- Depth of penetration test
- Contrast-detail analysis comparing anechoic cyst visibility (Correct answer)
- Doppler velocity accuracy
- Caliper distance measurement
Correct answer: Contrast-detail analysis comparing anechoic cyst visibility
Comparing anechoic cyst detectability between fundamental and harmonic modes reveals harmonic imaging's improvement in contrast resolution by reducing reverberation and clutter.
Question 5: During QA of a color Doppler system using a flow phantom, the color signal disappears below a certain depth. What does this finding most likely indicate?
- The PRF is set too high for the depth
- Doppler sensitivity has degraded at depth, possibly due to element dropout (Correct answer)
- The wall filter setting is too low
- The color map is inverted
Correct answer: Doppler sensitivity has degraded at depth, possibly due to element dropout
Loss of color Doppler signal at depth despite adequate flow in the phantom suggests reduced sensitivity, often from failing transducer elements that cannot detect low-amplitude Doppler shifts at distance.
Question 6: What does 'test object fog' refer to in the context of ultrasound phantom QA?
- Condensation on the phantom surface reducing acoustic coupling
- Low-level echoes that fill anechoic targets due to electronic noise or reverberation (Correct answer)
- Acoustic shadow caused by high-attenuation phantom materials
- Ghosting artifact from side lobe energy in the phantom
Correct answer: Low-level echoes that fill anechoic targets due to electronic noise or reverberation
Test object fog describes low-level echoes that fill supposedly anechoic cysts, caused by system noise, reverberation, or electronic noise degrading contrast resolution.
Question 7: Which phantom design feature allows simultaneous assessment of both axial and lateral resolution in a single image acquisition?
- Anechoic cysts arranged in a grid pattern
- A wire group oriented diagonally to the image plane
- Pin targets arranged in an L-shaped pattern at known separations axially and laterally (Correct answer)
- A flow tube running perpendicular to the scan plane
Correct answer: Pin targets arranged in an L-shaped pattern at known separations axially and laterally
An L-shaped arrangement of pin targets provides known separations along both the axial and lateral directions, enabling measurement of both resolution parameters in one scan.
ARDMS SPI Quality Assurance and Phantoms 4
What AIUM-recommended QA frequency is typically suggested for clinical ultrasound equipment used daily?