Q9 Digital Color Doppler Ultrasound System
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3)
Move the cursor by rotating the trackball to the start point of the one cycle and press Enter-key to fix it.
A second cursor “|” will appear.
4)
Rotate the trackball the end point of the cycle and press Enter-key to fix it.
5)
After the measurement, the value of Vs,Vd,RI,SD ratio,PI will appear on the screen.
Peak Velocity or Doppler frequency
Peak velocity over one cardiac cycle (Vpk)
Doppler Time Distance
Time distance between two cursors in ms. The invert is the heart beat rate if the two cursors are at one
cardiac cycle period. (T)
Spectral Velocity Time Integral (VTI)
VTI=
∑
Vpk *(delta t). Where delta t is T/N, N is the data point over one cardiac cycle.
Pulsatility Index (PI)
It can be used to represent the degree of pulse-wave damping at different arterial sites; the smaller the PI, the
greater the degree of damping. Typical value for CCA is 1.90+/-0.5.
PI = | (A-B)/TimeAvgPk |, TimeAvgPk=
Σ
Vpk/ N
Resistive Index (RI)
Vary from 0 to 1. It is an indicator of the circulatory resistance. Typical value for CCA is 0.75+/- 0.05.
RI = | (A-B) /A|
Note:
a)
In order to get accurate result, the PW image must be clear and high quality.
b)
Insure you fix the cursor at the exact place of cardiac systole and diastole
Manual editing of the envelope curve:
1:After you get the envelope curve press “Update”, the start point will be displayed in orange.
2:Move trackball to the start point, where you want to edit, press “Enter” key to enter into manual status.
3:Trace the curve by trackball, and press ”Enter” key to finish.
4:The envelope will be updated after being edited.
5:Select the cycle, the result the result will be displayed on the screen.