Quality Assurance and Lab Accreditation – Chapter 5

Vocabulary flashcards covering core terms related to ultrasound quality assurance, statistical analysis, equipment maintenance, performance testing, phantoms, and accreditation bodies.

Quality Assurance (QA)

A systematic program designed to ensure proper equipment operation, detect gradual changes, minimize downtime, reduce non-diagnostic exams, and cut repeat scans.

Quality Improvement (QI)

Ongoing evaluation of sonographer performance and scan quality with continuous feedback and training.

Gold Standard

The most accurate diagnostic test against which all other tests are compared (e.g., venography for DVT).

Sensitivity

The ability of a test to correctly identify positive cases; formula = A / (A + C).

Specificity

The ability of a test to correctly identify normal cases; formula = D / (D + B).

Accuracy

Overall correctness of a test in identifying both positive and negative results; formula = (A + D) / (A + B + C + D).

Reliability

Consistency of a test in repeatedly providing accurate results.

Positive Predictive Value (PPV)

Proportion of abnormal exams correctly identified as positive; formula = A / (A + B).

Negative Predictive Value (NPV)

Proportion of normal exams correctly identified as negative; formula = D / (D + C).

Chi-Square Test

Statistical method used to summarize sensitivity, specificity, PPV, NPV, and accuracy in one contingency table.

Preventative Maintenance

Scheduled evaluation, calibration, cleaning, and electrical safety checks performed to keep ultrasound equipment in optimal working condition.

Performance Testing

Routine activities that evaluate the imaging accuracy of an ultrasound system, including resolution, calibration, and registration checks.

Phantom (Test Object)

An objective standard used to calibrate and evaluate ultrasound equipment performance.

Calibration Test Object (AIUM Test Object)

Phantom with steel pins used to check measurement accuracy, resolution, and dead zone; has tissue-speed sound velocity but no attenuation.

Tissue-Mimicking Phantom

Grayscale test object with tissue-like speed, attenuation, scattering, and echogenicity used to assess contrast resolution and sensitivity.

Doppler Phantom

Device for evaluating Doppler flow direction, penetration depth, sample-volume location, and velocity accuracy; examples include flow, vibrating string, and moving belt phantoms.

Slice-Thickness Phantom

Phantom used to measure beam elevation resolution and detect overly thick sound beams that may create artifactual echoes in cystic structures.

Axial Resolution (LARRD)

Minimum reflector separation along the beam’s main axis that can be distinguished; tested with pins parallel to the beam.

Lateral Resolution (LATA)

Minimum reflector separation perpendicular to the beam’s main axis that can be distinguished; tested with pins perpendicular to the beam.

Elevational Resolution

Resolution in the slice-thickness dimension, evaluated with slice-thickness phantoms.

Dead Zone

Region at the top of the image where echoes cannot be accurately recorded; evaluated by scanning shallow pins in a test object.

Horizontal Registration

Accuracy of horizontal distance measurements on the image; assessed with calibration phantoms.

Vertical Registration

Accuracy of vertical distance measurements on the image; assessed with calibration phantoms.

Trackball Cleaning

Daily maintenance task that ensures smooth cursor movement and accurate caliper placement.

Lab Accreditation

Formal recognition that an ultrasound lab meets national standards for administration, protocols, and scan quality.

American Institute of Ultrasound in Medicine (AIUM)

Accrediting body offering accreditation in abdominal, small parts, gynecology, obstetrics, and vascular ultrasound.

Intersocietal Accreditation Commission (IAC)

Accrediting body specializing in vascular and echocardiography lab accreditation.

American College of Radiology (ACR)

Accrediting organization for abdominal, small parts, gynecology, obstetrics, and vascular ultrasound labs.

American Registry for Diagnostic Medical Sonography (ARDMS)

Credentialing organization for diagnostic medical sonographers.

Cardiovascular Credentialing International (CCI)

Credentialing body offering certifications in cardiovascular ultrasound specialties.

American Registry of Radiologic Technologists (ARRT)

Credentialing organization that also certifies sonographers through its sonography pathway.

Flow Phantom

Type of Doppler phantom that uses circulating fluid to simulate blood flow for velocity and direction testing.

Vibrating String Phantom

Doppler phantom employing an oscillating string to generate reproducible Doppler signals for system evaluation.

Moving Belt Phantom

Doppler test object featuring a belt with scatterers that moves to create controlled Doppler shifts.

Contrast Resolution

System ability to differentiate adjacent shades of gray; assessed with tissue-mimicking phantoms.

Anechoic Target Structure

Cyst-like region in a phantom used to test the system’s ability to display fluid-filled areas without internal echoes.

Equipment Tagging

Labeling of out-of-calibration or unsafe equipment to prevent clinical use until service is completed.