Pw/Cw Doppler Mode Checks - GE VIVID E9 Service Manual

GE H
EALTHCARE
D GA091568, R
IRECTION
4-3-5

PW/CW Doppler Mode Checks

4-3-5-1 Introduction
PW and CW Doppler are used to measure velocity (most often in blood).
Doppler mode can be done with a special pencil probe or with an ordinary probe. By using an ordinary
probe, you can first bring up a 2D picture for navigation purpose and then add PW/CW Doppler.
4-3-5-2 Preparations
1.) Connect one of the probes to the scanner.
-
2.) Turn ON the scanner
The 2D Mode window is displayed (default mode).
3.) If needed, adjust the Display's Brightness and Contrast setting.
4.) Press PW or CW to start Pulsed Wave Doppler (PW) or Continuous Wave Doppler (CW).
5.) Use the trackball to select the Area of Interest (Sample Volume) in PW or direction of interest in CW.
4-3-5-3 Adjust the PW/CW Doppler Mode controls
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.
• 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.
• Use Invert to reverse the vertical component of the spectral Doppler area of the display.
• Use Angle correction to steer the ultrasound beam to the blood flow to be measured.
4 - 42
5
EVISION
See 3-7-6 "Connecting Probes" on page 3-24
Section 4-3 - Functional checks
VIVID E9 S
for info about connecting the probes.
M
ERVICE ANUAL