GE Logiq 500, Руководство пользователя

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Doppler
LOGIQ 500 Basic Users Manual
2233658–100 Rev. 0
5–55
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Controls (cont’d)
B Pause Velocity Scale
Description Freezes the B-Mode image while keeping
the Doppler spectrum display active. Adjusts the velocity scale to accommodate
faster/slower blood flow velocities. Adjust
the size of the presentation to show a low
velocity scale for low flow and a higher
velocity scale for high flow.
Velocity scale determines PRF. If the
velocity goes off the scale (outside the
limits of pulsed Doppler), high PRF
activates and samples up to 3 gates.
The display updates velocity scale
parameters after adjusting the velocity
scale.
Accessing/
Changing To pause the B-Mode image, press
B Pause. The key backlights fully.
To cancel B-Mode image freezing, press
B Pause. The key semi-backlights.
NOTE: A bar is inserted in the display with
each velocity scale change that cannot be
measured across velocity scale changes.
Benefits The spectrum tracks the Doppler Sample
Volume Gate in real-time. Blood flow information is not cut off due to
the effect of aliasing.
Values Velocity range is in meters per second or
KHz, depending upon preset velocity scale
units. Velocity range is dependent on the
probe frequency.
Affects on
Other Controls B-Mode pause increases the Doppler
display quality.
NOTE: When pressing Freeze while in B
Pause and then unfreezing the image, a
preset selection will determine if the B
Pause key is released or the image
remains in B Pause. This is determined by
the Set Up/Custom Display menu page 12
“Auto B Melt at Unfreeze”.
The echo level measurement is not
available in B Pause. It is only available
on a frozen image.
When raising the velocity scale, the
spectrum waveform decreases in size;
when lowering the velocity scale, the
spectrum waveform increases in size.
Changes in the spectrum are relative to
changes in the velocity scale, that is, it
sizes accordingly.
When adjusting the velocity scale, Cine
memory is cleared.
Velocity scale units change with sample
volume size, depth, frame rate and
Doppler wall filter.
NOTE: The velocity scale changes when
angle correct is changed.
Bioeffects
Acoustic
Adjusting this control may cause minor
changes in acoustic output. Observe the
output display for possible effects.
Output
Hazard