GE Medical Systems 500, User Manual, Page: 272 / 636

OB Measurements and Formulas
LOGIQ 500 Basic Users Manual
2276612–100 Rev. 0
9–10

USA Method
Transf CALCS is only available with Realtime Doppler Calculation option installed
CRL
GS BPD
FL
AC USER1
OB
Report
HC USER3
USER2 USER4
USER5
AFI OB
Graph
OB
Report
ANATOMY
SURVEY
Select
Locatn
S/D
Ratio
RI
A/B
Ratio
TRACE
AUTO
Transf
CALCs
PI
1
HEART
RATE
OB
Graph
OB
Report
Page 1 Page 2
Page 3 Page 4
Figure 9–3. USA Sub-Menus
Calc
Mnemonic Calc Name
Input
Measurements Formula
Author
Reference
HR Heart Rate
(beats/minute) one 2 beat time (Measured
manually or automatically) HR[BPM]= 120[sec]/2
beat time[sec] n/a
GS Gestational
Sac three distances GS=(d1+d2+d3)/3+
3.6225 Hellman, A/OG,
103: 789,1969
CRL Crown Rump
Length one distance CRL=1.
0.31
0.049306xd1^2+
0.004057xd1^3+
0.000120456xd1^4 Hadlock,
Radiology,
182:501, 1992
FL Femur Length one distance FL = –3.91 + 0.427
(GA) – 0.0034 (GA)
2
Hadlock et al,
Radiology,
152:497 501
BPD Biparietal
Diameter one distance BPD = –3.08+0.41
(GA) – 0.000061 (GA)
3
152:497–501,
1984
AC Abdominal
Circumference circumference by trace, el-
lipse, circle or two distances AC = –13.3 + 1.61 (GA)
– 0.00998 (GA)
2
HC Head
Circumference circumference by trace, el-
lipse, circle or two distances HC = –11.48 + 1.56
(GA) – 0.0002548
(GA)
3
Hadlock et al,
Radiology,
152:497–501,
1984
Table 9–3. OB Calculation Formulas Part 1—USA Version Factory Defaults