B-K Medical Pro Focus 2202, User Manual

Page: 220 / 356

220 Chapter 15
PI (Pulsatility Index)
You can measure PI in different ways:
•
Automatic – the Doppler curve is drawn automatically and you position markers
on it.
•
Manual – you draw the Doppler curve manually (freehand).
•
Real-time – the system calculates and displays PI automatically in real time.
(See “Real-Time Measurements” below.)
Automatic To measure PI automatically:
1
Click Auto, then make sure that PI is selected.
2 Position one marker at the start systolic (SS) frequency.
3
Position the second marker at the end diastolic (ED) frequency.
The PI measurement is displayed to the left of the image.
If more than one cycle is included between the time cursors, the calculated PI is an
average over the cycles.
NOTE:
Make sure that the trace appears to be a good fit to the spectrum so that
the basis for the automatic calculation is correct.
Manual
To measure PI manually:
1 Click PI.
2
Position the marker on the start systolic (SS) frequency and click.
3 Draw a curve that traces a line along the whole maximum spectrum through the
peak systolic (PS) frequency, the minimum diastolic (MD) and onto the end
diastolic (ED) frequency.
4
Click.
The PI measurement is displayed to the left of the image.
If the traced curve covers more than one cycle, the PI is calculated as the average of
each cycle.
Real-Time Measurements
The following measurements can be made and displayed in real time so that they are
continually updated while the image is scanning:
Real Time appears in two places on the right side of the screen. The upper one is used
to turn real-time measurements on and off. The lower one is used to select the real-
time measurements you want.
• PS • MD • RI
• ED • PI • HR