GE Vivid S70, Руководство пользователя

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Measurement accuracy
Vivid S70 / S60
–
User Manual
8-97
BC092760-1EN 01
Measurement accuracy
General
When using the Measurement and Analysis (M&A) package, it is
important to keep in mind the different aspects that affect the
accuracy of the measurements. These include acoustical
properties, patient echogenicity, measurement tools and
algorithms, scanner setup (especially Field-of-view or Range
settings), probe type used, and operator inputs.
Sources of error
Image Quality
The accuracy of each measurement is highly dependent on
image quality. Image quality is highly dependent on system
design, operator variability, and patient echogenicity. The
operator variability and patient echogenicity are independent of
the ultrasound system.
Operator variability
One of the largest potential sources of error is operator
variability. A skilled operator can reduce this by optimizing the
image quality for each type of measurement. Clear identification
of structures, good probe alignment and correct cursor
placement is important. Because of pixel resolution, the
accuracy of a measurement decreases with decreasing distance
on screen. Therefore it is important when scaling the object on
the screen to avoid measuring objects that are too small.
NOTE: See also ‘Optimizing Measurement Accuracy’ on page 8-99 for
recommended techniques.
Image measurement
The accuracy in lateral direction is limited by the beam width and
the beam positioning. The radial accuracy is mainly limited by
the acoustic pulse length.