GE Vivid S5 N, Руководство по обслуживанию

Страница: 312 / 834

GE
P
ART
N
UMBER
FN091065, R
EVISION
2 VS5 N
AND
VS6 N
S
ERVICE
M
ANUAL
4-42 Section 4-4 - Image Testing
P R E L I M I N A R Y
• Adjust Power to obtain an acceptable image using the lowest setting possible.
NOTE: The Power setting affects all other operating modes.
Adjust the following settings to further optimize display of the image:
• Use Invert to reverse the color assignments in the color flow area of the display.
• Use Tissue priority to emphasize either the color flow overlay, or the underlying grey scale tissue
detail.
• Use Baseline to emphasize flow either toward or away from the probe.
• Use Radial and Lateral Averaging to reduce noise in the color flow area. Radial and Lateral
Averaging smooths the image by averaging collected data along the same horizontal line. An
increase of the lateral averaging will reduce noise, but this will also reduce the lateral resolution.
4-4-4 PW/CW Doppler Mode Checks
4-4-4-1 Introduction
PW and CW Doppler are used to measure velocity (most often in blood).
Doppler mode can be used 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 purposes and then add PW/CW Doppler.
4-4-4-2 Preparations
1.) Connect one of the probes to the scanner.
See ‘Connecting Probes” on page 3-71 for information about connecting the probes.
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.
4-4-4-3 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.