Scanning Modes
176 Vivid S5/Vivid S6 User Manual
R2424458-100 Rev. 2
Radial Averaging
Smooths the image by averaging collected data along the
same radial line. An increase of the radial averaging will reduce
noise, but this will also reduce the radial resolution.
Power
Controls the amount of acoustic power applied. When power is
reduced the signal to noise ratio is reduced, so that the image
may become noisier.
Cine Compound (Freeze only)
Calculates and displays cineloops generated from a temporal
averaging of multiple consecutive heart cycles. The number of
cycles averaged is controlled from the Soft menu rocker. The
number of averaged cycles displayed on the top left corner.
Using Tissue Tracking
1. From 2D or TVI Modes, press ALT on the control panel and
select the
TISSUE TRACKING assignable.
2. Adjust
TRACKING START (assignable) close to the R-peak.
3. Adjust
TRACKING END (assignable) near the T-wave.
4. Use the trackball to position the ROI frame over the area
to be examined.
The assignable con-
trols of the trackball
are displayed in the
trackball status bar
in the bottom right
corner of the screen.
5. Press SET. The instruction Size should be highlighted in the
trackball status bar. If not, press
SET again to select Size.
Note: If the trackball control Pointer is selected, press
TRACKBALL to be able to select between Position and Size
controls.
6. Use the trackball to adjust the dimensions of the ROI.
Optimizing Tissue Tracking
• To reduce quantification noise (variance), the Nyquist limit
should be as low as possible, without creating aliasing. To
reduce the Nyquist limit, reduce the scale while in TVI.
• To check for aliasing, freeze the loop and apply velocity
trace (Press
FREEZE and Q-ANALYSIS), see also Chapter 8,
"Quantitative Analysis" on page 375).
• The main use of Tissue Tracking is to map positive systolic
displacements. This means that
TRACKING START and
TRACKING END assignables should be adjusted to pick out
the systolic phase of the cardiac cycle: Adjust Tracking
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