GE Voluson 730Pro, Basic User Manual

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Spectral Doppler Mode
7.2.2.6 Invert
This function inverts the CW spectrum display in relation to the direction of the flow. The displayed
spectrum is inverted around the baseline. The velocity or frequency scale changes accordingly.
Use
[
Invert
]
when necessary to change the spectral display orientation.
It is possible in both read- and write mode.
Forward flow indicates:
Blood flow toward the transducer
Reverse flow indicates: Blood flow away from the transducer
key unlit Normal: Forward flow above the baseline
Reverse flow below the base line
key lit: Inverted: Reverse flow above the baseline
Forward flow below the baseline
7.2.2.7 Angle Correction
To get optimum resolution and accuracy from Doppler measurements, the angle that exists between
the ultrasound beam and the blood flow should be maintained between 0 and 20 degrees.
However, due to anatomical limitations an angle of 55 to 65 degrees is common in peripheral vascular
applications. The blood flow velocity calculation based on the incident angle of the ultrasound beam to
the axis of the vessel can be determined as follows.
The vessel must be displayed in longitudinal section and the angle cursor must be positioned parallel
to the vessel axis (in the area of measurement).
Angle correction adjusts the Doppler scale and is only necessary for velocity display (cm/s, m/s)
according to the Doppler equation.
The cursor angle can be changed in 1° increments in both directions continuously.
By
pressing the angle knob repeatedly the angle correction is changed
from + 60° to 0° and to – 60°.
No indication to set the angle correction will appear in the measuring programs.
Remarks:
* The actual angle is displayed on the screen [SV Angle ...].
*
Adjusting the angle is always possible, in write mode and read mode.
*
The angle correction line on the CW cursor is at the same time the depth marker for the focus.
Voluson
®
730Pro - Basic User Manual
105831 Rev. 0
7-17