Measuring Velocity Time Integral
Introduction
Use the Velocity Time Integral (VTI) option to measure multiple parameters from a tracing of a spectral Doppler signal to calculate the following secondary measurements:
- Peak Velocity
- Peak Gradient
- Mean Velocity
- Mean Gradient
For spectral Doppler velocity measurements, it is not necessary to mark the baseline. The VTI tool automatically identifies the baseline of a calibrated image.
Steps
- Right-click the image to display a context menu.
- Select Annotations > VTI.
- Place the cursor inside the image at the position where you want to begin drawing the VTI measurement.
- Click once to begin drawing the point-to-point measurement in the Doppler image. The control points display as circles.
- Move the cursor in a forward motion to the next point location and click again to establish that point as a VTI measurement.
- Right-click to complete the annotation.
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Optional: After you create a VTI annotation, you can delete the annotation or click and drag the control points to reposition them, but you cannot move the VTI annotation. See Manipulating Annotations.
Results
As you complete the VTI annotation, Synapse displays the VTI and secondary annotation values (listed above) in an ordered list in the Results overlay. Hover over an annotation in the Results overlay to highlight the annotation in the image.
For Protocol measurements, the Viewer sends the VTI and all secondary values included in the Protocols list.
Additional Options
Click 
on the icon menu.