GE Medical Systems 500, User Manual, Page: 271 / 636

OB Measurements and Formulas
LOGIQ 500 Basic Users Manual
2276612–100 Rev. 0
9–9

Osaka University Method (cont’d)
Calc
Mnemonic Calc Name Input Measurements Formula
Author
Reference
EFBW Estimated Fetal
Body Weight Average of BPD, Average
of FTA and Average of FL EFBW=1.25647x
BPD^3+3.50655
x FTA x FL+6.3 (<5000g)
IUGR=1.229 x
BPD^3+3.063 x
FTA x FL–24.6
Curve data is available in
the Advanced Reference
Manual Osaka University
Method 1989,
3 by Univ. of
Osaka
CTAR Cardio–Thoracic
Area Ratio four distances or two
areas CTAR = (d1 x d2) /
(d3 x d4) x 100
or a1 / a2 x 100 Y.Chiba Fetal
Diagn Ther 1990 :
5 : 175 – 188
PLI Preload Index two Doppler blood flow
velocities PLI = | v1 / v2 | Y.Chiba Fetal
Diagn Ther 1990 :
5 : 168 – 174
EF Ejection Fraction two distances on M–Mode
(End–diastolic dimension
and End–systolic
dimension on M–Mode) EF = (1 – Ds^3 / Dd^3) n/a
Vmax Maximum Velocity
in descending
aorta one Doppler blood flow
peak velocities Vmax = input n/a
S/D Ratio Systolic / Diastolic
Ratio two Doppler blood flow
peak velocities S/D = Vsystole /
Vdiastole
*NOTE*
n/a
A/B Ratio Velocities Ratio two Doppler blood flow
peak velocities A/B = V
1
/V
2
n/a
Pl Pulsatility Index two Doppler blood flow
peak velocities and
TA_MAX Pl = (Vmax – V
diastole
) /
TA_MAX
*NOTE*
n/a
RI Resistivity Index two Doppler blood flow
peak velocities RI = (Vmax – V
diastole
) /
Vmax *NOTE*
n/a
*NOTE*: V
diastole
= V
min
or V
end–diastole
(depends on preset selection)
Table 9–2. OB Calculation Formulas—Osaka University Factory Defaults (cont’d)