GE Vivid S70 User Manual page 153

NOTE:
NOTE:
NOTE:
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Vivid S70 / S60 User Manual
BC092760-1EN 01
The scale value may affect FPS, Low Velocity Reject, and
Sample Volume.
• Adjust Low Velocity Reject to remove low velocity blood
flow and tissue movement that reduces image quality.
• Adjust Variance to detect flow disturbances.
• Adjust Sample volume (SV) to a low setting for better flow
resolution, or a higher setting to more easily locate disturbed
flows.
• Adjust Frequency to optimize the color flow display. Higher
settings improve resolution. Lower settings improve depth
penetration and sensitivity. This does not affect the
frequency used for 2D and M-Mode.
Frequency setting may affect FPS, SV and Low Velocity
Reject.
In certain selected applications when entering color flow
imaging (CF), there is a button available called
AutoFrequency. If this button is depressed, the application
will automatically select for the user a frequency appropriate
for the depth of the ROI. When the feature is enabled, the
frequency control is no longer available to the user until the
AutoFrequency button is released again. And while the
AutoFrequency feature is active the scale control is
controlling velocity and not PRF as indicated on the touch
panel rotary itself. If the user turns the desired velocity
control to a higher value than what is achievable at the
maximum PRF attainable at the current depth, the feature
will automatically lower the frequency to still attempt to
achieve the requested velocity, if this is possible within the
range of frequencies supported. Moving the ROI between
different depths, the user may experience that the system
selects a different frequency if that is more suitable, as is
displayed on the screen, but will attempt where possible to
retain the velocity span requested from the user interface.
Releasing the AutoFrequency button will again make the
mnual frequency selection rotary available to the user and
the scale button will again be controlling the PRF directly.
• Adjust Power to obtain an acceptable image using the
lowest setting possible.
The Power setting affects all other operating modes.
Color Mode
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