
8-15
Chapter 8 Measurements and Calculations
The equations used for D RI measurement are as follows:
X
Manual Trace
This is a basic measurement that is only available in Spectral Doppler mode. Specify one point on a
Spectral Doppler image, and trace a curve from that point to calculate the blood flow velocity, average
velocity, RI, and Pulsatility Index (PI).
1. Select Manual Trace on the monitor or touch screen.
2. Trace the curve. Measurement is taken in the same way as ‘Line Trace’.
3. When the measurement is nished, its result is shown on the screen. Displayed results will vary
depending on the settings in Setup > Measurement > Parameter1
X
PS: Peak Systolic Velocity
X
MD: Min Diastolic Velocity
X
ED: End Diastolic Velocity
X
TAmax: Time Averaged Max Velocity
X
TAMEAN: Time Average Mean Velocity
X
PI: Pulsatility Index
X
RI: Resistivity Index
X
PS/ED: PS ED Ratio
X
ED/PS: ED PS Ratio
X
HR
The equations used for Manual Trace measurement are as follows:
X
Duration of flow
VTI
meanV =
X
PS
EDPS
RI
−
=
X
Vmean
EDPS
PI
−
=
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