QA/stats Flashcards
4 test devices/phantoms used as part of a QA program to assist sono to validate the accuracy and consistency of the US systems
- test object
- tissue equivalent phantom
- doppler phantom
- slice thickness phantom
Hydrophone is used to evaluate (4)
Pulse amplitude
PD
PRP
Period
What does the hydrophone do
Measures acoustic output / pressure
What do the tissue phantoms and test object measure? (3)
Penetration
Registration
Resolution
What QA method used refraction properties of water to evaluate beam pattern and measure intensity
Schlieren method
A calorimeter is used to measure the
Power of the beam
Converts sound energy into heat - measures tiny changes in temperature
Dead zone
Distance closest to the transducer in which imaging cannot be performed
Hydrophone specifically evaluates which parameters (3)
Acoustic output - relationship btwn amt of acoustic pressure and the voltage produced. Measures period, PRP, PD
Sensitivity - define and formula
Ability to detect PRESENCE of disease
TP/TP+FN
Specifity - define and formula
Ability to detect ABSENCE of disease
TN/TN+FP
Negative predictive value - define and formula
How often test is correct when its negative for the disease
TN/TN+FN
Accuracy - define and formula
% of exams that agree with gold standard
TP + TN/ TP+TN+FP+FN
Elastography depicts tissue ….
Stiffness
Positive predictive value - define and formula
How often test is correct when positive for disease
TP/TP+FP
Quality assurance
- Routine evaluation of (2)
- What does it provide assessment of? What does it ensure?
- What testing device will QA program usually use?
Routine evaluation of the transducers AND ultrasound system
Provides assessment of image quality, ensures consistency
Testing via tissue equivalent phantom
Beam profiler measures
Transducer characteristics
AIUM 100 test object cannot evaluate (3)
Penetration
Grey scale
Compression
What does the AIUM 100 test object evaluate?
System sensitivity
Transducer characteristics evaluated by
Beam profiler
Force-balance system measures
Power of the sound beam
Acoustic output testing considers only the (2)
Pulser/beam former
and transducer
Which testing device can simulate pulsatile or retrograde flow?
Moving string phantom
*TO evaluates
System sensitivity
*Beam profiler is a testing device that measures:
Transducer characteristics
*The ability to place reflections in proper positions regardless of the imaging orientation describes
Registration accuracy
*Testing device a QA program will likely use
Tissue equivalent phantom
*what evaluates operation of the US system?
Tissue equivalent phantom
What can the TEP measure that the test object cannot? (3)
Compression, penetration, contrast resolution
