Intraexaminer and Interexaminer Variability in 3D Fetal Volume Measurements During the Second and Third Trimesters of Pregnancy.
OBJECTIVE
To assess intraexaminer and interexaminer reliability of 3-dimensional fetal sonographic measurements.


METHODS
Three-dimensional fetal organ volumes (head, kidney, total thigh volume, and fractional thigh volume) were acquired during the second and third trimesters, with the addition of placental volume in the second trimester, by 2 different experienced, blinded sonographers. Fifty-eight fetuses were examined from 21 to 39 weeks' gestation. Intraexaminer and Interexaminer reliability was assessed with Bland-Altman plots, and their 95% limits of agreement and intraclass correlation coefficients.


RESULTS
The most significant interexaminer error was observed in the second-trimester kidney volume (95% limits of agreement, ± 110%), and the best agreement was for the third-trimester fractional thigh volume (95% limits of agreement, ± 25%) and second-trimester head volume (95% limits of agreement, -7%-25%). Second- and third-trimester intraclass correlation coefficient results were all greater than 0.75, apart from second-trimester kidney volume intraexaminer (0.374) and interexaminer (0.061) measurements, second-trimester placenta interexaminer measurements (0.390), and third-trimester kidney interexaminer measurements (0.647).


CONCLUSIONS
Three-dimensional fetal sonographic volumes of the head, kidney, total thigh, and placenta have limited reproducibility, and improvements in measurement techniques are needed before they can be used routinely to assess fetal growth. The 3-dimensional fractional thigh volume can be reliably obtained in the late third trimester.
Maternal and Fetal Health Research Center, Institute of Human Development, University of Manchester, Manchester, England.|St Mary's Hospital, Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Center, Manchester, England.
Louise E
LE
Simcox
Maternal and Fetal Health Research Center, Institute of Human Development, University of Manchester, Manchester, England.|St Mary's Hospital, Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Center, Manchester, England.
Lucy E
LE
Higgins
Maternal and Fetal Health Research Center, Institute of Human Development, University of Manchester, Manchester, England.|St Mary's Hospital, Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Center, Manchester, England.
Jenny E
JE
Myers
Maternal and Fetal Health Research Center, Institute of Human Development, University of Manchester, Manchester, England.|St Mary's Hospital, Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Center, Manchester, England.
Edward D
ED
Johnstone
D005260:Female; D020567:Fetal Weight / Q000502:physiology*; D005333:Fetus / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D015588:Observer Variation; D009929:Organ Size; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods*
3-dimensional sonography; Virtual Organ computer-aided analysis; fractional thigh volume; head volume; kidney volume; obstetric ultrasound; placental volume; reliability; total thigh volume