GE Medical Systems 500, User Manual, Page: 277 / 636

OB Measurements and Formulas
LOGIQ 500 Basic Users Manual
2276612–100 Rev. 0
9–15

European Method (cont’d)
Calc
Mnemonic Calc Name
Input
Measurements Formula
Author
Reference
TAD Transverse
Abdominal
Diameter one distance Curve data is
available in the
Advanced Reference
Manual ERIKSEN
OFD Occipito Frontal
Diameter one distance Known LMP Case: Hansmann:
Ultraschalldiag–nos
tik in Begurtshilfe
Unknown LMP Case:
tik in Begurtshilfe
und Gynakologie
1985
Ft Foot Distance one distance Curve data is
available in the
Advanced Reference
Manual PARIS
EFW Estimated Fetal
Weight Average of BPD and
Average of AC [cm] EFW[g] = 10
ƞ
(1.7288
+ 0.09184*BPD +
(0.02581* AC) +
(0.00011*BPD*AC))
Shepard/
Warsoff
FL/AC FL/AC ratio Average of FL and
Average of AC FL/AC Hadlock, AJR, 141 :
979, 1983
FL/BPD FL/BPD ratio Average of FL and
Average of BPD FL/BPD Hadlock, AJOG,
141 : 759, 1987
CI Cephalic Index Average of BPD and
Average of OFD BPD/OFD short
distance HC/long
distance HC Hadlock, AJR, 137 :
83, 1981
HC/AC HC/AC ratio Average of HC and
Average of AC HC/AC
FL/Ft FL/Ft ratio Average of FL and
Average of Ft FL/Ft
BD/BPD BD/BPD ratio Average of BPD and
Average of BD BD/BPD
D/S Ratio Diastolic/
Systolic Ratio two Doppler blood flow
peak velocities D/S = V
diastole
/
V
systole
*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=(V
max
– V
diastole
)/
V
max
*NOTE*
n/a
*NOTE*: V
diastole
= V
min
or V
end–diastole
(depends on preset selection)
Table 9–5. OB Calculation Formulas—European Version Factory Defaults (cont’d)