Chapter 7 - Working With Measurements
Measuring in the 2D Window
Terason t3000 / Echo Ultrasound System User Guide
162
AFI Q1
,
AFI Q2
,
AFI Q3
, and
AFI Q4
are used to calculate the amniotic fluid index (AFI), and
the
OFD
measurement is used to calculate the cephalic index (CI).
Calculating Estimated Fetal Weight
The Terason software can estimate the weight of a fetus. Terason uses the Hadlock
formula (see Appendix D -
) based on the abdominal circumference,
head circumference, and femur length measurements. To use a measurement setup other
than Hadlock, see
on page 250. If you choose a different
setup, the selected setup may not support the EFW calculation.
To calculate the estimated fetal weight, complete the following steps:
1.
Perform an obstetrical
exam
.
2.
Click .
3.
Select
AC
from the Measurement menu and use the Ellipse tool to measure the
abdominal circumference.
4.
If necessary, click
Live
and acquire a view for the head circumference measurement,
then click
Freeze
.
5.
Select HC from the Measurement menu and use the
Ellipse
tool to measure the head
circumference.
6.
If necessary, click
Live
and acquire a view for the femur length measurement, then
click
Freeze
.
7.
Select
FL
from the Measurement menu and use the Distance tool to measure the femur
length.
When the Terason software places
AC
,
HC
, and
FL
on an obstetrical exam, it
automatically calculates the estimated fetal weight (EFW).