User's Manual

Acclarix LX3 Series Diagnostic Ultrasound System User Manual Imaging
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Table 5-3 PW Mode Touch Screen Controls
5.3.3. HPRF
Conventional PW Doppler scales are limited by the Nyquist limit. High Pulse Repetition Frequency
(HPRF) allows the system to exceed the Nyquist limit by having multiple Doppler pulses in the body at
the same time. In HPRF imaging, multiple Doppler gates are displayed since the multiple Doppler
pulses could be giving information from different depths. HPRF is automatically invoked when needed
to maintain the requested depth and scale. For example, if the system is at a high scale and you move
the cursor deeper, the system may automatically invoke HPRF. This can also happen if the cursor is
deep and you increase scale.
If HPRF is active, you will see multiple Doppler gates on the reference image. If you do not want to be
in HPRF, decrease the scale or move the primary PW gate to a shallower location until only one gate
is displayed.
Image Type
Spectral Doppler supports image presets for Low Flow,
Medium Flow and High Flow.
Frequency
This determines the Doppler transmit frequency used for
imaging.
Auto Trace
Press to activate the Auto Trace function on a real-time or
frozen PW Doppler strip.
The Auto Trace function automatically traces the spectral
Doppler waveform and records several measurements on
selected waveforms.
Trace Side
Press one of the three options to specify which side of the
Doppler baseline to take measurements from:
Up: traces positive portion of waveform (above baseline).
Down: traces negative portion of waveform (below baseline).
Both: traces waveform on both sides of baseline.
Acoustic
Power
Adjusts the acoustic output power of the activated transducer.
It is only available in live imaging. Higher acoustic power
numbers correspond to increased sensitivity in the Doppler
display and improved penetration, but the ALARA principle
should be followed in actual clinical situations.