GE Vivid S70, Руководство пользователя

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Measurement accuracy
Vivid S70 / S60
–
User Manual
8-99
BC092760-1EN 01
Optimizing Measurement Accuracy
Probe selection
Select a transducer appropriate for the application, and optimize
the transducer frequencies used. Higher imaging frequencies
provide better resolution, but less penetration than lower
frequencies. Lower Doppler frequencies can measure higher
max velocities, and at greater depths, but with less velocity
resolution than higher Doppler frequencies.
Field of View
All display modes should be adjusted so that the area of interest
covers as large portion of the display as possible. Use
Depth ,
Angle , Zoom , Horizontal Sweep and Velocity controls to
optimize the different modes.
Cursor Placement
All measurements are dependent on the accuracy of their “input”
data. Consistency and precision in placing cursors and drawing
traces correctly on the images are important.
NOTE: Avoid placement of the cursor near the top of the image, close to
the transducer, when using convex or linear probes.
Measurement Uncertainties
The accuracy percentages reported below are based on data
taken with optimum control settings, using calibrated phantoms
and test equipment.
The calibration was done for the basic measurable parameters:
Distance, Time and Velocity.
Independent sources of uncertainty contribute to a total
uncertainty by a RMS (Root Mean Square) combination of the
sources. Refer to the discussions above regarding
measurement accuracy and sources of error when reading the
table below.
NOTE: In Cardiac, several Doppler measurements have an auto feature
(CAD – Cardiac AutoDoppler). Cardiac AutoDoppler uses
automatic algorithms to analyze a Doppler spectrum over
multiple heart cycles, and then displays a set of suggested
landmarks. Adjust – if needed – and approve these landmarks
before they are extracted and used for initialization of existing