Hprf Mode; Real Time Trace - GE VOLUSON 730Pro Basic User Manual

7.1.2.11.1

HPRF Mode

The maximum clearly measurable flow velocity (Nyquist Limit) is determined by the measuring depth
of the sample volume and the related run time of the ultrasound.
By a further increase of the Doppler PRF (High PRF mode, HPRF) the Nyquist Limit can be
increased. Thus in addition to the main sample volume one or more sample volume gates appear in
lesser depth. During examinations make sure that these additional sample volumes (virtual gates) do
not lie in echo-rich areas, as these lead to interferences in the Doppler signal.
Further it has to be noted that blood flows recorded by these virtual gates are overlaying the actual
Doppler signal of the main sample volume.
When the maximum is exceeded, the HPRF mode is automatically switched on.
Virtual gates are being displayed and the [HPRF] appears on the monitor.
Changing of the velocity range display from kHz to m/s or cm/s is to be performed in the
PW Sub Menu (chapter 7.1.3).
Remarks:
* The current sampling frequency is displayed on the screen [PRF.... respectively HPRF...].
* Changing the velocity range is only possible in write mode. No function in read mode.
* The HPRF mode does not function in Duplex- and Triplex mode (Simultaneous mode).
* The HPRF mode is impossible with linear array probes.
7.1.2.12

Real Time Trace

With the "Real Time Auto Trace" function the envelope curve of the Doppler spectrum (maximum
velocities) and the corresponding evaluation is automatically displayed on the monitor.
Select the [RT Trace] item to display the curve for the maximum velocities (envelope curve)
simultaneously with the Doppler spectrum.
When starting the Doppler spectrum, the following parameters are displayed and updated every time
a new heart cycle is detected:
PSV Peak Systolic Velocity, marked with line
EDV End Systolic Velocity, marked with line
RI Resistance Index (calculated from PSV and EDV)
HR Heart Rate
®
Voluson 730Pro - Basic User Manual
105831 Rev. 0
unlit: Real Time Trace is switched off.
it: Real Time Trace is switched on.
Spectral Doppler Mode
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