Chapter 5 - Working With Scan Modes Using Color and Power Doppler Image Controls
Terason t3000 / Echo Ultrasound System User Guide 121
The increment value for each click depends on the current range, as defined in the table
below. For example, if the PRF setting is 4000, each time you click the right or left arrow,
the Terason software adds or subtracts 500 Hz from that value, until the selected value
falls into a lower or higher range.
Increasing the PRF also increases the Thermal Index (TI) value (refer to General
Description of Indices on page 268 for more information about thermal indices).
Inverting the Doppler Display (Color Invert)
In Color Doppler and Directional Power Doppler modes, you can invert the color scale.
This feature is not available with the Power Doppler mode.
Normally, the color red is assigned to positive frequency shifts (flow toward the
transducer), and blue is assigned to negative frequency shifts (flow away from the
transducer). However, this color assignment can be reversed by clicking the Color Inver
t
button. Whether the display is inverted or not, flow toward the transducer is assigned the
colors of the top half of the color bar, and flow away from the transducer is assigned the
colors of the bottom half of the color bar.
When you click the Color Inver
t button, the Color Doppler reference bar and the color of
the scan data within the Region of Interest are both inverted.
Invert may be used when scanning the internal carotid artery (ICA), for example. In
general, flow in this vessel goes away from the transducer. If Invert is enabled, the ICA
flow displays in shades of red. The color bar displays shades of blue on the top half, and
shades of red on the bottom.
To invert the Doppler colors, click the Color Invert button:
Color Invert Button
PRF Ranges
Range (Hz) Increment (Hz)
200-500 50
500-1000 100
1000-3000 250
2000-5000 500
5000-up 1000
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