5-20 Image Optimization
5.6 PW/CW Doppler Mode
PW (Pulsed Wave Doppler) mode or CW (Continuous Wave Doppler) mode is used to provide blood
flow velocity and direction utilizing a real-time spectrum display. The horizontal axis represents time,
while the vertical axis represents Doppler frequency shift.
PW mode provides a function for examining flow at one specific site for its velocity, direction and
features. CW mode proves to be much more sensitive to high-velocity flow display. Thus, a combination
of both modes will contribute to a much more accurate analysis.
CW imaging is an option.
Adjustment items, such as SV, Steer, Duplex, Triplex, iTouch and HPRF, are not available in CW mode.
5.6.1 Basic Procedures for PW/CW Mode Exam
1. Select a high-quality image during B mode or B + Color (Power) mode scanning, and adjust to
position the area of interest in the center of the image.
2. Press <PW>/<CW> to adjust the sampling line,
The sampling status will be displayed in the image parameter area in the top-right corner of the
screen as follows:
PW Sampling Line
Adjustment
SV
Angle
SVD
CW Sampling Line
Adjustment
Angle
CW Focus Depth
3. Set the position of the sample line by moving the trackball left and right. Set the SVD by moving the
trackball up and down. Adjust the angle and SV size according to the actual situation.
4. Press <PW>/<CW> or <Update> again to enter PW/CW mode and perform the examination. You
can also adjust the SV size, angle and depth in real-time scanning.
5. Adjust the image parameters during PW/CW mode scanning to obtain optimized images.
6. Perform other operations (e.g., measurement and calculation) if necessary.
If “sampling line displaying” is selected, then the screen will display the sampling line all the time and
pressing <M> one will lead to entering M mode directly. For details, see “5.1.3 Quickly Saving Image
Settings” chapter.
5.6.2 PW/CW Mode Image Parameters
In PW/CW mode scanning, the image parameter area in the top-right corner of the screen displays the
real-time parameter values as follows:
Wall
Filter
SV
Position
CW Parameter F G PRF WF SVD Angle
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