General Procedures and Functional Checks
4-30 Vivid T9/Vivid T8 – Basic Service Manual
5795591-100 English Rev. 3
4-3-23 Adjust the TVI Controls
• 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 value.
NOTE: The Scale value also affects the frame rate. There is a trade
off between the frame rate and quantification noise.
TVI provides velocity information only in the beam direction.
The apical view typically provides the best window since the
beams are then approximately aligned to the longitudinal
direction of the myocardium (except near the apex). To
obtain radial or circumferential tissue velocities, a
parasternal view must be used. However, from this window
the beam cannot be aligned to the muscle for all the parts of
the ventricle.
NOTE: PW will be optimized for Tissue Velocities when activated
from inside TVI.
4-3-24 Basic Measurements
NOTE: The following instructions assume that you first scan the patient
and then press Freeze.
4-3-24-1 Check Distance and Tissue Depth Measurement
1. Press Measure once to display an active caliper.
2. Move the trackball to position the active caliper at the start
point (distance) or the most anterior point (tissue depth).
3. Press Set to fix the start point.
4. The system fixed the first caliper and displays a second
active caliper.
5. Move the trackball to position the second active caliper at
the end point (distance) or the most posterior point (tissue
depth).
6. Press Set to complete the measurement. The system
displays the distance or tissue depth value in the
measurement results window.
NOTE: To toggle between active calipers, rotate Cursor Select button.
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