GE Vivid S60N, Basic Service Manual

Page: 176 / 478

D
IRECTION
FR091521, R
EVISION
1 V
IVID
S60N/V
IVID
S70N B
ASIC
S
ERVICE
M
ANUAL
4-30 Section 4-3 - Functional Checks
P R E L I M I N A R Y
4-3-6-3 Using PW/CW Doppler Modes
4-3-6-3-1 Alternative 1
1) Press PW or CW . A scanning screen is displayed with a Doppler cursor on the 2D mode image and
a Doppler spectrum in the lower part of the screen.
2) Use the trackball to position the Doppler cursor line and in PW the sample volume location over the
area of interest.
3) In PW, adjust the Sample Volume .
NOTE: Sample Volume adjustment may affect the Scale, Frame rate and LV rej. settings.
4-3-6-3-2 Alternative 2
1) Press Cursor on the control panel. A cursor line is displayed on the 2D image.
2) Select the cursor type on the Touch panel.
3) With the trackball adjust the position of the cursor line.
4) Press PW or CW .
4-3-6-4 Optimizing PW/CW Doppler Modes
The use of preset gives optimum performance with minimum adjustment. If necessary, the following
controls can be adjusted to further optimize the PW/CW modes display:
• Adjust the Active mode gain to set the gain in the spectral Doppler area.
• Adjust Low velocity reject to reduce unwanted low velocity blood flow and tissue movement.
• In PW mode, adjust Sample volume to low setting for better resolution, or higher setting to more
easily locate the disturbed flows. Adjustment of the Sample volume may affect the PRF (Nyquist
limit) settings.
• Adjust the Compress setting to balance the effect of stronger and weaker echoes and obtain the
desired intensity display.
• Adjust Frequency to optimize flow display. Higher setting will improve resolution and the lower
setting will increase the depth penetration.
• Adjust Frame rate to a higher setting to improve motion detection, or to a lower setting to improve
resolution.
NOTE: Frequency and Frame rate settings may affect the Low Velocity Reject.
• Adjust Power to obtain an acceptable image using the lowest setting possible. This is particularly
important in CW mode, as the energy duty cycle is 100% (constant).
NOTE: The Doppler Power setting affects only Doppler operating modes.
Adjust the following settings to further optimize the display of the image.
• Use the Horizontal sweep to optimize the sweep speed.
• To view signal detail, adjust Scale to enlarge the vertical spectral Doppler trace. Velocity range
directly controls the pulse repetition frequency, which is responsible for the setting of the Nyquist
limit (the ability to detect maximum velocity without aliasing).
• Use Invert to reverse the vertical component of the spectral Doppler area of the display.
CAUTION
Use all noise reduction controls with care. Excessive
application may obscure low level diagnostic information.