Sources Of Measurement Errors - FujiFilm SonoSite Edge II User Manual

Table 6-2: M Mode Measurement and Calculation Accuracy and Range
M Mode Measurement
Accuracy and Range
Heart Rate
a
Full scale for distance implies the maximum depth of the image.
b
An RMI 413a model phantom with 0.7 dB/cm MHz attenuation was used.
c
Full scale for time implies the total time displayed on the scrolling graphic image.
d
FUJIFILM SonoSite special test equipment was used.
Table 6-3: PW Doppler Mode Measurement and Calculation Accuracy and Range
Doppler Mode
Measurement
Accuracy and Range
Velocity cursor
Frequency cursor
Time
a
FUJIFILM 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.

Sources of measurement errors

In general, two types of errors can be introduced into the measurement:
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: 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.
Measurement references
System Tolerance
< +/- 2% plus (Full Scale
* Heart Rate/100)%
System Tolerance
< +/- 2% plus 1% of full
b
scale
< +/- 2% plus 1% of full
b
scale
< +/- 2% plus 1% of full
c
scale
Accuracy By Test Method
c Acquisition
Phantom
Accuracy By
Test Method
Acquisition Phantom
Acquisition Phantom
Acquisition Phantom
Range
d 5-923 bpm
a
Range
0.01 cm/sec-
550 cm/sec
0.01kHz-20.8
kHz
0.01-10 sec
6-3