Quality Assurance

What is quality assurance?

Systemic evaluation of ultrasound system and transducers to ensure diagnostic image quality and consistency

What is a true positive result? True negative?

1. True positive = test matches gold standard, both are positive

2. True negative = test matches gold standard, both are negative

What is a false positive result? False negative?

1. False positive = test does not match gold standard, test says there is disease when there isn’t

2. False negative = test does not match gold standard, test says there is no disease when there is

What is sensitivity?

Ability of a test to detect disease when it is present

What is specificity?

Ability of a test to rule out disease when it is not present

What is positive predictive value?

Measures how often test is correct when positive for disease

What is negative predictive value?

Measures how often test is correct when negative for disease

What is accuracy?

Ability of a test to correctly identify disease or lack of diease

What is a phantom?

Device with characteristics similar to tissue used to test imaging performance

What is the dead zone?

Distance between front surface of transducer and first identifiable echo

What can eliminate or move a dead zone?

Standoff pad

Identify this image.

1. Dead zone

2. Axial resolution

3. Horizontal resolution

4. Horizontal distance calibration

5. Vertical distance calibration

6. Solid nodule

7. Cystic area

What values have bioeffects been confirmed for?

1. Non-focused SPTA > 100 mW/cm²

2. Focused SPTA > 1 W/cm²

What is ALARA?

As low as reasonably achievable