User guide

Chapter 4: Measurements and Calculations 59
Measurements
To make a correction, select Undo
on-screen, backtrack with the touchpad, or
press the
BACKSPACE key.
d Press the
SET key to complete the trace.
e Save the calculation.
For information on the automatic trace tool, see
“To trace automatically (Doppler)” on
page 46.
To calculate Isovolumic Relaxation Time
(IVRT)
1 On a frozen Doppler spectral trace, press the
CALCS key.
2 From the calculations menu, select MV and then
select IVRT.
A vertical caliper appears.
3 Using the touchpad, position the caliper at the
aortic valve closure.
4 Press the
SELECT key.
A second vertical caliper appears.
5 Using the touchpad, position the second caliper
at onset of mitral inflow.
6 Save the calculation. (See “To save a
calculation” on page 47.)
To calculate Delta Pressure: Delta Time
(dP:dT)
To perform the dP:dT measurements, the CW
Doppler scale must include velocities of 300 cm/s
or greater on the negative side of the baseline.
(See “Spectral trace controls” on page 29.)
1 On a frozen CW Doppler spectral trace, press
the
CALCS key.
2 From the calculations menu, select MV, and
then select dP:dT.
A horizontal dotted line with an active caliper
appears at 100 cm/s.
3 Position the first caliper along the waveform at
100 cm/s.
4 Press the
SELECT key.
A second horizontal dotted line with an active
caliper appears at 300 cm/s.
5 Position the second caliper along the waveform
at 300 cm/s.
6 Save the calculation. (See “To save a
calculation” on page 47.)
To calculate Aortic Valve Area (AVA)
The AVA calculation requires a measurement in 2D
and two measurements in Doppler. After the
measurements are saved, the result appears in the
patient report.
1 Measure from LVOT (2D):
a On a frozen 2D image, press the
CALCS key.
b From the calculations menu, select LVOT D.
c Position the calipers. (See “Working with
calipers” on page 43.)
d Save the calculation. (See “To save a
calculation” on page 47.)
2 Measure from LVOT, and then measure from AV
(Doppler):
•For Vmax, see “To measure peak
velocity” on page 57. From the
calculations menu, select AV, select sample
site, and then select Vmax.
• For VTI, see “To calculate Velocity Time
Integral (VTI)” on page 57. From the
calculations menu, select AV, select sample
site, and then select VTI.
To calculate Qp/Qs
The Qp/Qs calculation requires two measurements
in 2D and two measurements in Doppler. After the
measurements are saved, the result appears in the
patient report.
1 On a frozen 2D image, press the
CALCS key.
2 Do the following to measure from LVOT D and
again to measure from RVOT D: