SonoSite titan - Sources of Measurement Errors; Acquisition Error; Algorithmic Error; Terminology and Measurement Publications

Chapter 8: References 191
References
Sources of Measurement Errors
In general, two types of errors can be introduced into the measurement: acquisition error and
algorithmic error.
Acquisition Error
Acquisition error includes errors introduced by the ultrasound system electronics relating to signal
acquisition, signal conversion, and signal processing for display. Additionally, computational and
display errors are introduced by the generation of the pixel scale factor, application of that factor to
the caliper positions on the screen, and the measurement display.
Algorithmic Error
Algorithmic error is the error introduced by measurements, which are input to higher order
calculations. This error is associated with floating-point versus integer-type math, which is subject
to errors introduced by rounding versus truncating results for display of a given level of significant
digit in the calculation.
Terminology and Measurement Publications
Terminology and measurements comply with AIUM published standards.
Table 3: PW Doppler Mode Measurement and Calculation Accuracy and Range
Doppler Mode
Measurement Accuracy
and Range
System
Tolerance
Accuracy
By
Test
Method
a
Range
Velocity cursor < +/- 2% plus 1%
of full scale
b
Acquisition Phantom 0.01 cm/sec-
550 cm/sec
Frequency cursor < +/- 2% plus 1%
of full scale
b
Acquisition Phantom 0.01kHz-20.8 kHz
Time < +/- 2% plus 1%
of full scale
c
Acquisition Phantom 0.01-10 sec
a. SonoSite special test equipment was used.
b. Full scale for frequency or velocity implies the total frequency or velocity magnitude, displayed on the
scrolling graphic image.
c. Full scale for time implies the total time displayed on the scrolling graphic image.