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Measurement Formulas
LOGIQ 7/LOGIQ 7 Pro Advanced Reference Manual
2
-
17
Direction 5116269-100 Rev. 2
Formulas–OB
Table 2-6: OB Calculation Formulas
Calc
Mnemonic
Calc Name
Input
Measurements
Formula
Author
Reference
AC
Abdominal
Circumference
circumference by
trace, ellipse, circle
or two distances
AC=-13.3+1.61 (GA) -
0.00998 (GA)
2
Hadlock et al,
Radiology,
152:497-501,
1984
BPD
Biparietal
Diameter
one distance
BPD = -3.08+0.41 (GA) -
0.000061 (GA)
3
CRL
Crown Rump
Length
one distance
CRL=1.
0.31
0.049306xd1^2+
0.004057xd1^3+
0.000120456xd1^4
FL
Femur Length
one distance
FL = -3.91 + 0.427 (GA) -
0.0034 (GA)
2
GS
Gestational Sac
three distances
GS [wk] = 1.42450142 *
(d1+d2+d3)/3+ 3.6225
HC
Head
Circumference
circumference by
trace, ellipse, circle
or two distances
HC=-11.48 + 1.56 (GA) -
0.0002548 (GA)
3
HC
Head
Circumference
one ellipse
HC [mm] = 2.325 * (BPD
[mm]^2 + OFD [mm]^2)^0.5
Hansmann,
Ultrasound
Diagnosis in
Obstetrics and
Gynecology,
438-9, 1985
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