The efficacy assessment of thigh volume in predicting intrauterine fetal growth restriction by three-dimensional ultrasound

Fractional Limb Volume in Spina Bifida Fetuses as an Assessment Tool for Postnatal Ambulation

BACKGROUND

Prenatal fractional limb volume (FLV) can be used to assess muscle atrophy in fetuses with myelomeningocele.

OBJECTIVE

We hypothesize that FLV in fetal myelomeningocele (fMMC) repair is different from postnatal repair (PNR). Assessing intrauterine muscle development can predict ambulation.

METHODS

A prospective observational study was performed from July 2012 to April 2016. Demographics, clinical outcomes, and FLV of the fetal thigh were assessed by ultrasound. Ambulation videos were collected from patients over 30 months of age. FLV was compared between the fMMC and PNR groups and between ambulators and non-ambulators. Two-sample t test, ANOVA, Spearman's rho correlation, and Bland-Altman plots were used for analysis. A p value <0.05 was used for statistical significance.

RESULTS

Fifty-nine patients were included, 24 had fMMC and 35 had PNR. Videos were obtained in 47 cases (73%). There was no difference in baseline demographics between the groups. There was no significant change in the fMMC group between the FLV at initial presentation and the repeat at 34 weeks gestation (54.5 ± 28.2 and 62.2% ± 16.4; p = 0.6). In contrast, the FLV in the PNR decreased between the initial evaluation and the repeat at 34 weeks (54.1 ± 27.7 to 35.8 ± 34.1%; p = 0.04). FLV at 34 weeks gestation was higher in the fMMC group as compared to the PNR group (62.2 ± 16.4 vs. 35.8 ± 34.1%; p = 0.02). There was no difference in FLV between ambulators and non-ambulators either at initial evaluation (p = 0.8) or at 34 weeks gestation (p = 0.6).

CONCLUSION

Lower FLV in the PNR group compared to fMMC may suggest in utero muscle atrophy. No correlation was seen between FLV and subsequent ambulation; however, future larger studies may be needed.

Fetal thigh and upper-arm volumes by three-dimensional ultrasound to predict low postnatal body mass index

OBJECTIVE

To assess the usefulness of estimating fetal upper arm and thigh volumes as predictors of low postnatal body mass index (BMI) using three-dimensional ultrasonography (3DUS) with extended imaging virtual organ computer-aided analysis (XI VOCAL).

METHODS

This prospective cross-sectional study analyzed 300 singleton pregnancies between 33 and 41 weeks of gestation. The Hadlock 4 formula was used to estimate fetal weight. The XI VOCAL 10 planes method was used to assess fetal upper arm and thigh volumes. After delivery, the newborns' BMI was evaluated and considered low (≤10th percentile) or normal (>10th percentile). We determined receiver operating characteristics (ROC) curves and respective areas under the curves for the percentiles of fetal weight and fetal thigh and upper arm volumes.

RESULTS

Of the 300 newborns, BMI was ≤10th percentile for 21 and >10th percentile for 279 newborns. The area under the ROC curve for fetal weight, obtained using the Hadlock formula, and fetal upper arm and thigh volumes, obtained by 3DUS, were 0.801, 0.930 and 0.924, respectively. We determined the sensitivity and specificity of the three parameters for predicting low postnatal BMI and found values of 85.70% and 65.60%, respectively, for fetal weight, 90.48% and 88.17%, respectively, for fetal thigh volume, and 76.19% and 92.47%, respectively, for fetal upper arm volume.

CONCLUSION

Fetal upper arm and thigh volumes estimated using 3DUS with XI VOCAL were effective predictors of low postnatal BMI.

Soft tissue volume of upper arm in predicting small-for-gestational-age fetuses using three-dimensional ultrasound

PURPOSE

To assess the value of fetal soft tissue volume (STV) of the upper arm in predicting small-for-gestational-age (SGA) fetuses using three-dimensional (3D) ultrasound (US).

METHODS

We used 3D US to test the accuracy of fetal STV of the upper arm measurement in predicting SGA in a prospective cross-sectional study.

RESULTS

Fetal STV of the upper arm assessed by 3D US can differentiate SGA fetuses from appropriate-for-gestational-age (AGA) fetuses. Using the 5th percentile as the cutoff, the sensitivity of fetal upper arm STV in predicting SGA fetuses was 84.1%, specificity, 93.4%, positive predictive value, 71.1%, negative predictive value, 96.8%, and overall accuracy, 91.9%. In addition, the diagnostic accuracy of fetal arm STV was better than that of the biparietal diameter, abdominal circumference, and femur length.

CONCLUSION

Fetal STV of upper arm assessment by 3D US is a novel method to predict SGA fetuses.

Reprodutibilidade do volume de membros fetais pela ultrassonografia tridimensional utilizando o método XI VOCAL

OBJETIVO: Avaliar a reprodutibilidade do volume do braço e coxa fetais aferido pela ultrassonografia tridimensional utilizando o método eXtended Imaging Virtual Organ Computer-aided AnaLysis (XI VOCAL). MATERIAIS E MÉTODOS: Realizou-se estudo de reprodutibilidade com 43 fetos normais entre 20 e 37 semanas. Para o cálculo do volume do braço e coxa fetais utilizou-se o método XI VOCAL com delimitação de 10 planos consecutivos. Para o cálculo da variabilidade interobservador, um examinador realizou uma medida do volume do braço e coxa dos 43 fetos, enquanto um segundo examinador, sem o conhecimento prévio dos resultados do primeiro examinador, realizou uma segunda medida dos mesmos volumes. Utilizaram-se, para os cálculos estatísticos, o coeficiente de correlação intraclasse (ricc), gráficos de Bland-Altman e teste t-Student pareado (p). RESULTADOS: Observou-se alta reprodutibilidade interobservador. Para o volume do braço, obtiveram-se ricc = 0,996 (intervalo de confiança [IC] 95%: 0,992; 0,998) e média das diferenças = 0,13 ± 1,29% (95% limites de concordância: -2,54; +2,54%). Para o volume da coxa, obtiveram-se ricc = 0,997 (IC 95%: 0,995; 0,999) e média das diferenças = 0,24 ± 7,60% (95% limites de concordância: -7,6; +7,6%). CONCLUSÃO: O volume do braço e coxa fetais aferido pela ultrassonografia tridimensional utilizando o método XI VOCAL apresentou elevada reprodutibilidade interobservador.

Fractional limb volume--a soft tissue parameter of fetal body composition: validation, technical considerations and normal ranges during pregnancy

OBJECTIVES

The main goals were to provide normal reference ranges for fractional limb volume as a new index of generalized fetal nutritional status, to evaluate the reproducibility of fractional fetal limb volume measurements during the second and third trimesters of pregnancy, and to demonstrate technical considerations for this technique.

METHODS

This was a prospective, cross-sectional study of gravid women during mid to late pregnancy. Fractional limb volumes were based on either 50% of humeral or femoral diaphysis length. Each partial volume was subdivided into five equidistant slices that were centered along the mid-arm or mid-thigh. Slices were traced manually to obtain fractional arm (AVol) or fractional thigh (TVol) volume. Reproducibility studies were performed, using Bland-Altman plots, to assess blinded interobserver and intraobserver measurement bias and agreement. Selected images were chosen to demonstrate technical factors for the acquisition and analysis of these parameters. Reference charts were established to describe normal ranges for AVol and TVol.

RESULTS

Three hundred and eighty-seven subjects were scanned to include 380 AVol (range, 1.1-68.3 mL) and 378 TVol (range 2.0-163.2 mL) measurements between 18.0 and 42.1 weeks' menstrual age. No gender differences were found in these soft tissue measurements (AVol, P = 0.90; TVol, P = 0.91; Mann-Whitney test). Intraobserver mean bias +/- SD and 95% limits of agreement (LOA) for fractional limb volumes were: 2.2 +/- 4.2% (95% LOA, - 6.0 to 10.5%) for AVol and 2.0 +/- 4.2% (95% LOA, - 6.3 to 10.3%) for TVol. Interobserver bias and agreement were - 1.9 +/- 4.9% (95% LOA, - 11.6 to 7.8%) for AVol and - 2.0 +/- 5.4% (95% LOA, - 12.5 to 8.6%) for TVol. Technical factors were related to image optimization, transducer pressure, fetal movement, soft tissue compression and amniotic fluid volume.

CONCLUSIONS

Fractional limb volume assessment may improve the detection and monitoring of malnourished fetuses because this soft tissue parameter can be obtained quickly and reproducibly during mid to late pregnancy. Careful attention should be placed on technical factors that can potentially affect optimal acquisition and analysis of these volume measurements.

Predicting fetal growth restriction with renal volume using 3-D ultrasound: efficacy evaluation

Early detection and management of fetal growth restriction (FGR) is very important in prenatal care and daily practice, because FGR fetuses may suffer increased risk of perinatal morbidity and mortality. Renal volume (RV) might be one of the important parameters of fetal growth. Yet, no prenatal assessment of fetal RV in FGR fetuses by 3-D ultrasound (US) has been reported. We undertook a prospective and cross-sectional study using quantitative 3-D US to assess the efficacy of fetal RV in predicting FGR. All fetuses were singletons and were followed-up to delivery to determine whether they had FGR complications. In total, 221 fetuses without FGR and 28 fetuses with FGR were included. Our results showed fetal RV assessed by 3-D US can differentiate fetuses with FGR from fetuses without FGR. The best predicting threshold for FGR is at the tenth percentile of fetal RV. Using the tenth percentile as the cutoff, the efficacy of fetal RV in predicting FGR was sensitivity 96.4%, specificity 95.9%, positive predictive value 75.0%, negative predictive value 99.5% and accuracy 96.0%, respectively. Fetal RV assessed by 3-D US can be applied to detect FGR prenatally. We believe fetal RV assessment using 3-D US is a useful test in detecting fetuses with FGR.

Ultra-som tridimensional na avaliação do volume de membros fetais

O volume de membros fetais é conhecido marcador do estado nutricional e de crescimento intra-uterino. O surgimento da ultra-sonografia tridimensional tem permitido avaliação volumétrica mais precisa, principalmente de estruturas com formas irregulares, como é o caso dos órgãos fetais. A ultra-sonografia tridimensional pelo modo multiplanar surge como o método mais eficiente para a avaliação do volume de membros fetais, tornando-se o exame mais acurado para a predição de peso ao nascimento. Atualmente, por meio desse método, já se consegue monitorar o desenvolvimento do tecido macio, sendo capaz de diagnosticar mais precocemente os distúrbios do crescimento intra-uterino. Em nosso meio, em que há altos índices de desvios do crescimento fetal e ao mesmo tempo baixa assistência neonatal de qualidade, a maior difusão do método poderia contribuir de forma decisiva para a diminuição nos índices de morbidade e mortalidade perinatais.

Prenatal detection of fetal growth restriction by fetal femur volume: efficacy assessment using three-dimensional ultrasound

As fetal growth restriction (FGR) may have increased risks with perinatal morbidity and mortality, it is very important to detect FGR prenatally. Fetal femur dysplasia is associated with a variety of congenital syndromes and FGR as well. To date, no prenatal assessment of fetal FV in predicting FGR using three-dimensional (3D) ultrasound (US) has been reported. In this study, we used 3D US to test the efficacy of fetal femur volume (FV) measurement in predicting FGR. We calculated the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and efficacy of fetal FV assessed by 3D US in detecting FGR according to the Bayes' theorem. All the fetuses were singletons and were followed up to delivery to determine whether they were complicated with FGR or not. In total, 304 fetuses without FGR and 42 fetuses with FGR were included for FV assessment in utero by 3D US. Our results showed fetal FV assessed by 3D US can differentiate fetuses with FGR from fetuses without FGR well. The best predicting threshold for FGR is at the 10th percentile of FV. Using the 10th percentile as the cutoff, the sensitivity of fetal FV in predicting FGR was 71.4%, specificity 94.1%, positive predictive value 62.5%, negative predictive value 96.0% and accuracy 91.3%. In addition, fetal FV is superior to fetal biparietal diameter and fetal abdominal circumference in predicting FGR. In conclusion, fetal FV assessed by 3D US can be applied to detect FGR well prenatally. We believe fetal FV assessment by 3D US would be a useful test in detecting fetuses with FGR.