Ultrasound in Obstetrics & GynecologyVolume 32, Issue 3 p. 282-282 Wednesday, 27 August 2008Free Access OC121: Abstract withdrawn First published: 11 August 2008 https://doi.org/10.1002/uog.5529AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume32, Issue3Special Issue: 18th World Congress on Ultrasound in Obstetrics and GynecologyAugust 2008Pages 282-282 RelatedInformation

Objectives To develop individualized growth assessment (IGA) standards for upper (ThC(u)) and middle (ThC(m)) fetal thigh circumferences using three-dimensional ultrasonography.Methods A prospective, longitudinal sonographic study of 30 fetuses was performed beginning at 18 weeks' menstrual age. Second-trimester sonographic parameters were measured from three-dimensional volume data to establish IGA standards. Normal infant growth outcomes were confirmed using modified Neonatal Growth Assessment Scores (m(3)NGAS(51)). ThC(u) and ThC(m) were studied in more detail. Rossavik growth model specification procedures, based on the slopes of the second-trimester growth curves, were developed for both ThC(u) and ThC(m). Third-trimester growth trajectories and birth measurements were subsequently predicted for these parameters. Percentage deviations during the third trimester and percentage differences at actual birth age were used to compare observed and predicted measurements. The 95% ranges for Growth Potential Realization Index (GPRI) values for both types of thigh circumference were determined. Values for m(3)NGAS(51) using GPRI(ThC(u)), GPRI(ThC(m)) and GPRI(ThC(o)) (original method) were compared.Results The 30 newborns had no postnatal evidence of abnormal growth. Two examiners demonstrated a satisfactory measurement bias of mean +/- SD 2.1 +/- 3.6 (95% limits of agreement, -4.9 to 9.1)% for ThC(m) and 3.3 +/- 4.1 (95% limits of agreement, -4.8 to 11.4)% for ThC(u). Rossavik functions fitted parameter trajectories well, with mean R-2 values of 99.5 +/- 0.4% for ThC(u) and 99.6 +/- 0.3% for ThC(m). By fixing coefficients k at their mean values, their respective fits did not change, and the variabilities of coefficients c and s were significantly reduced. For ThC(u), coefficient c was significantly related to the second-trimester slope (R-2 = 98.6%), as was s to c (R-2 = 91.0%). For ThC(m), coefficient c was significantly related to the second-trimester slope (R2 = 98.6%), as was s to c (R-2 = 85.6%). Third-trimester growth trajectories, derived from second-trimester slopes for individual fetuses, had third-trimester deviations of 0.07 +/- 3.7% for ThC(u) and -0.04 +/- 3.7% for ThC(m). Percentage differences at birth age were 16.8 +/- 10.2% for ThC(u) and 8.9 +/- 9.5% for ThC(m). With correction for systematic overestimations, the mean GPRI values were 103.7 (95% range, 90-121)% for ThC(u) and 101.6 (95% range, 88-118)% for ThC(m). Corresponding mean +/- SD m(3)NGAS(51) values, using GPRI(ThC(u)), GPRI(ThC(m)) and GPRI(ThC(o)), were 203 +/- 11%, 201 +/- 10% and 200 +/- 9%, respectively.Conclusions Fetal thigh circumference can be measured reliably and evaluated using standard IGA methods. Both ThC(u) and ThC(m) give similar results in the third trimester but neonatal thigh circumference predictions are improved by using ThC(m). Corresponding GPRI(ThC(m)) values are closer to the ideal value of 100% and can be used in m(3)NGAS(51) calculations for assessment of neonatal growth outcome. Copyright (C) 2008 ISUOG. Published by John Wiley & Sons, Ltd.

Individualized growth assessment (IGA) compares anatomic measurements to their expected 3rd TM trajectories, with each fetus being its own control. The Rossavik growth model uses 2nd TM velocity slopes to derive model coefficients. Slope data is usually obtained from 2 or 3 scans between 18 and 26 weeks, menstrual age (MA). This study examines the feasibility of IGA model specification from only 2 scans at 14 and 18 weeks, MA. This is a prospective longitudinal study of 27 fetuses that had 3DUS scans between 14 and 38 weeks, MA. Standard biometry (HC, AC, FDL) was obtained. Soft tissue parameters also included mid-thigh circumference (ThC), fractional arm volume (AVol) and fractional thigh volume (TVol). EFW was calculated from head and abdominal cubes (Deter, 1988). Linear regression was used to calculate slopes from Early (14, 18 week) and Late (18, 21, 24 week) scans. Growth curves of fractional limb volumes were linearized using a cube root transformation. Rossavik model coefficients were determined and predicted 3rd TM trajectories specified (Deter, 1987). Mean 3rd TM average percent deviations (AV%Dev) were compared between Early and Late groups. *Statistical significance was at P < 0.05. Although small differences were found for predicted HC and FDL, both models yielded comparable results. Individualized fetal growth standards can be determined from biometry obtained at 14 and 18 week scans. Since early growth velocities critically define the accuracy of 3rd trimester predictions, the inter-observer reliability of these earlier measurements must be carefully examined before these standards are used clinically.

To re-examine the use of Individualized Growth Assessment (IGA) in predicting BW with standard EWT functions and those utilizing soft tissue parameters. A prospective longitudinal study of 44 fetuses was performed using 3D ultrasound. Standard biometry (BPD, AC, FDL), soft tissue parameters (fractional arm, AVol, and thigh volume, TVol) and head (A) and abdominal (B) cubes were measured. Using 2nd trimester data, growth models were specified that predicted sonographic parameters at 38 weeks and at actual birth age. An EWT function based on A and B (Deter RL, et al. JCU 1989; 17 : 83–88) and functions that included AVol or TVol (Lee W, et al. UOG 2006; 28 : 389) were applied. Actual and predicted BW's were compared. Mean and SD of % differences were taken as measures of systematic and random prediction errors, the former evaluated by t-test and the latter by F-test. 44 infants were delivered with BW of 3332 ± 397 g, at 38.8 ± 1.3 weeks, MA. In 26, the interval between 38 weeks and delivery was > 0.5 weeks permitting evaluation of Growth Cessation (GC) vs. Growth-To-Delivery (GTD) assumptions. GC and GTD groups were defined, depending on which assumption gave % differences closer to the ideal value of zero. All systematic errors greater than 4.0% were statistically significant from zero. All GTD fetuses identified by the latter 3 EWT methods were detected by the A,B EWT method. Two main growth patterns occurred after 38 weeks. The A, B EWT function effectively identified these patterns and gave BW predictions for each that were similar to those obtained previously, greater than 12 weeks before delivery.

variables could improve ultrasound prediction of fetal macrosomia over prediction which relies on the commonly used formulas for the sonographic estimation of fetal weight. Methods: The δ SVM algorithm was used for binary classification between two categories of weight estimation: >4000 g and <4000 g. Clinical and sononographic input variables of 100 pregnancies suspected of having LGA fetuses were tested. Results: Thirteen of 38 features were selected as contributing variables that distinguish birth weights of below 4000 g and of 4000 g and above. Considering 4000 g as a cut-off weight the pattern recognition algorithm predicted macrosomia with a sensitivity of 81%, specificity of 73%, positive predictive value of 81% and negative predictive value of 73%. The comparative figures according to the combined criteria based on two commonly used formulae generated from regression analysis were 88.1%, 34%, 65.8% and 66.7%. Conclusions: The δ SVM algorithm provides a prediction of LGA fetuses comparable to that of other commonly used formulae generated from regression analysis. The better specificity and better positive predictive value suggest potential value for this method and further accumulation of data may improve the reliability of this approach.

Background: Individualized growth assessment (IGA) compares anatomic measurements to their expected 3 rd TM trajectories, with each fetus being its own control. The Rossavik growth model uses 2 nd TM velocity slopes to derive model coefficients. Slope data is usually obtained from 2 or 3 scans between 18 and 26 weeks, menstrual age (MA). This study examines the feasibility of IGA model specification from only 2 scans at 14 and 18 weeks, MA. Methods: This is a prospective longitudinal study of 27 fetuses that had 3DUS scans between 14 and 38 weeks, MA