Can Three-Dimensional Ultrasound Be Used for the Assessment of the Fetal Lung Volume in Cases of Congenital Diaphragmatic Hernia?

Three-Dimensional Ultrasound Evaluation of Lung Volume in Fetuses with Abdominal Wall Defect

INTRODUCTION

Abdominal wall defects (AWDs) interfere with postnatal respiratory parameters. We aimed to evaluate lung volume (LV) in fetuses with AWD using three-dimensional (3D) ultrasound (US) and to correlate AWD with the type (omphalocele and gastroschisis) and size of the defect and neonatal morbidity and mortality.

METHODS

This prospective observational study included 72 pregnant women with fetuses with AWD and a gestational age <25 weeks. The data on abdominal volume, 3D US LV, and herniated volume were acquired every 4 weeks up to 33 weeks. LV was compared with normal reference curves and correlated with abdominal and herniated volumes.

RESULTS

Omphalocele (p < 0.001) and gastroschisis (p < 0.001) fetuses had smaller LV than normal fetuses. LV was positively correlated with abdominal volume (omphalocele, r = 0.86; gastroschisis, r = 0.88), whereas LV was negatively correlated with omphalocele-herniated volume/abdominal volume (p < 0.001, r = -0.51). LV was smaller in omphalocele fetuses that died (p = 0.002), were intubated (p = 0.02), or had secondary closure (p < 0.001). In gastroschisis, a smaller LV was observed in fetuses discharged using oxygen (p = 0.002).

CONCLUSION

Fetuses with AWD had smaller 3D LV than normal fetuses. Fetal abdominal volume was inversely correlated with LV. In omphalocele fetuses, a smaller LV was associated with neonatal mortality and morbidity.

Right Bochdalek congenital diaphragmatic hernia: a tertiary center's experience over 13 years

Background

Right Bochdalek congenital diaphragmatic hernia (RB-CDH) is far less common than left Bochdalek congenital diaphragmatic hernia, accounting for only 13% of cases. There are limited published data on the outcomes and survival rate of RB-CDH.

We aimed at investigating the clinical characteristics and analyzing the risk factors of survival in neonates with RB-CDH treated in our center over a period of 13 years.

Results

Fifteen infants with RB-CDH were identified. Most of the patients were full term (74%). The mean birth weight was 2.90± 0.72 kg. The ratio of male to female was 2:1. The mean APGAR score at 1 min was 5.31±2.34, and 7.30±1.59 at 5 min. Ten patients (67%) were imaged by antenatal ultrasound. Eleven patients (73.33%) survived to go for surgical repair. The hernia sac was found in 5 patients (45%). Most hernial defects were closed in a primary fashion. The mean age at the operative repair was 8.11±9.90 days. The average NICU stay for all patients was 40.47±50.38 days. The mean follow-up period was 20.45±9.34 months. Three patients had postoperative complications. The total survival rate in neonates with RB-CDH was 9/15 (60%). Nine out of 11 (82%) neonates survived after surgical repair. Four patients (27%) died before surgical repair. Ventilation-related bilateral pneumothorax was a contributing cause of death in three patients. Birth weight was found lower in the non-survivor’s group (P < 0.05). Moreover, the degree of pulmonary hypertension was more severe among non-survivors. No statistical significance was observed between other variables and mortality.

Conclusion

We found that low birth weight and the presence of severe PHTN were risk factors for mortality in neonates with RB-CDH. These results are in line with previous studies on prognostic factors in CDH. Ventilator-related pneumothorax appears to be a significant contributing cause of death. Long-term follow-up studies of infants born with RB-CDH are needed as small number of cases limits large-volume RB-CDH studies.

Reproducibility of Liver-to-Thorax Area Ratio Ultrasound Measurements in Congenital Diaphragmatic Hernia

OBJECTIVES

The aim of this study was to investigate the reproducibility of a standardized method to assess the ultrasound liver-to-thoracic area ratio in fetuses with congenital diaphragmatic hernia.

METHODS

We selected 24 images of 9 fetuses diagnosed with left-sided at our institution between January 2010 and December 2017. Eight operators (1 maternal-fetal medicine specialist and 7 sonographers) reviewed the selected images and assessed the ultrasound liver-to-thoracic area ratio according to a standardized protocol. We evaluated the correlation between operators using the intraclass correlation coefficient and compared agreement between the sonographers and a physician with experience in measuring the ultrasound liver-to-thoracic area ratio using a Bland-Altman analysis.

RESULTS

Good intraoperator reproducibility was observed for the standardized ultrasound liver-to-thoracic area ratio (intraclass correlation coefficient, 0.78). Good agreement among sonographers and the physician was also observed for the standardized measurements (bias, 0.01; precision, 0.03; limits of agreement, -0.05 to + 0.07).

CONCLUSIONS

We demonstrated that good intraoperator and interoperator reproducibility of ultrasound liver-to-thoracic area ratio assessment is feasible after standardizing the method in our center.

The role of three-dimensional ultrasonography fetal lung volume measurement in the prediction of neonatal respiratory function outcome

BACKGROUND

Respiratory distress is commonly encountered among premature babies immediately after birth resulting in significant neonatal morbidity or mortality.

OBJECTIVES

To evaluate the possible correlation between three dimensional fetal lung volumes (FLVs) and neonatal respiratory outcomes.

STUDY DESIGN

A cohort study included 100 pregnant women who participated in the study and were divided into two groups; group A (n: 50 - women pregnant ±34-37 weeks) and group B (n: 50 - women pregnant ±37⁺¹ to 40 weeks). A three dimensional measurement of the right fetal lung was made using virtual organ computer-aided analysis (VOCAL) software then correlated to neonatal respiratory functions namely Apgar score at birth and the occurrence of respiratory distress syndrome (RDS).

RESULTS

In group A, FLV was negatively correlated with Apgar score and the occurrence of RDS. In group B, FLV showed no statistical correlation with Apgar score and the occurrence of RDS.

CONCLUSIONS

Three dimensional fetal lung volumes might be an accurate noninvasive predictor for the development of RDS among preterm fetuses.

Reproducibility of Lung-to-Head Ratio Ultrasound Measurements in Congenital Diaphragmatic Hernia

OBJECTIVES

This study investigated the reproducibility of standardization of lung-to-head ratio measurements in congenital diaphragmatic hernia (CDH) at our center among sonographers after we standardized the method.

METHODS

We reviewed ultrasound images of 12 fetuses with CDH at Mayo Clinic from 2010 to 2016. Nine operators (1 maternal-fetal medicine specialist with experience in measuring the lung-to-head ratio and 8 sonographers), who were blinded to previous findings, reviewed 33 selected images from 12 fetuses with left CDH. The method for lung-to-head ratio measurement was standardized before starting the measurements. The lung-to-head ratio was assessed by different methods to obtain the lung areas: anteroposterior, longest, and area tracing. We evaluated the correlation between operators using the intraclass correlation coefficient (ICC). We also compared agreement between the sonographers and a physician with experience in measuring the lung-to-head ratio using a Bland-Altman analysis.

RESULTS

The methods with the best interoperator reproducibility were the standardized anteroposterior lung-to-head ratio (ICC, 0.69) and the standardized lung-to-head ratio tracing (ICC, 0.65) compared to the longest lung-to-head ratio (ICC, 0.56). The standardized lung-to-head ratio tracing had the best agreement among sonographers and the physician (bias, 0.11; limits of agreement, -0.27 to +0.49) than the anteroposterior lung-to-head ratio (bias, 0.35; limits of agreement, -0.13 to + 0.83) and the longest lung-to-head ratio (bias, 0.27; limits of agreement, -0.35 to +0.89).

CONCLUSIONS

We demonstrated that the lung-to-head ratio tracing method has high interoperator reproducibility and the best agreement among the operators at our center. Further multicenter studies are necessary to confirm our results.

Growth Patterns of Fetal Lung Volumes in Healthy Fetuses and Fetuses With Isolated Left-Sided Congenital Diaphragmatic Hernia

OBJECTIVES

To evaluate fetal lung growth using 3-dimensional sonography in healthy fetuses and those with congenital diaphragmatic hernia (CDH).

METHODS

Right and total lung volumes were serially evaluated by 3-dimensional sonography in 66 healthy fetuses and 52 fetuses with left-sided CDH between 20 and 37 weeks' menstrual age. Functions fitted to these parameters were compared for 2 groups: (1) healthy versus those with CDH; and (2) fetuses with CHD who survived versus those who died.

RESULTS

Fetal right and total lung volumes as well as fetal observed-to-expected right and total lung volume ratios were significantly lower in fetuses with CDH than healthy fetuses (P< .001) and in those fetuses with CDH who died (P< .001). The observed-to-expected right and total lung volume ratios did not vary with menstrual age in healthy fetuses or in those with CDH (independent of outcome).

CONCLUSIONS

Lung volume rates were lower in fetuses with left-sided CDH compared to healthy fetuses, as well as in fetuses with CDH who died compared to those who survived. The observed-to-expected right and total lung volume ratios were relatively constant throughout menstrual age in fetuses with left-sided CDH, suggesting that the origin of their lung growth abnormalities occurred before 20 weeks and did not progress. The observed-to-expected ratios may be useful in predicting the outcome in fetuses with CDH independent of menstrual age.

Recent advances in sonographic imaging of fetal thoracic structures

Recent ultrasonographic methods applied in the evaluation of fetal thoracic structures and anomalies are presented. Fetal lung volumetric assessment by 3D ultrasonography, analysis of the thoracic wall by 3D-rendered image and 3D skeletal-mode imaging, intrathoracic vessel evaluation by 3D power Doppler ultrasonography, analysis of heart anatomy and abnormalities by 4D spatiotemporal image correlation, identification of normal and abnormal intrathoracic almost isoechogenic structures by volume contrast imaging and evaluation of the heart and great vessels by 3 and 4D inverse mode will be reviewed.

Three-dimensional ultrasonographic assessment of fetal total lung volume as a prognostic factor in primary pleural effusion

OBJECTIVES

The purpose of this study was to predict perinatal outcomes using fetal total lung volumes assessed by 3-dimensional ultrasonography (3DUS) in primary pleural effusion.

METHODS

Between July 2005 and July 2010, total lung volumes were prospectively estimated in fetuses with primary pleural effusion by 3DUS using virtual organ computer-aided analysis software. The first and last US examinations were considered in the analysis. The observed/expected total lung volumes were calculated. Main outcomes were perinatal death (up to 28 days of life) and respiratory morbidity (orotracheal intubation with mechanical respiratory support >48 hours).

RESULTS

Twelve of 19 fetuses (63.2%) survived. Among the survivors, 7 (58.3%) had severe respiratory morbidity. The observed/expected total lung volume at the last US examination before birth was significantly associated with perinatal death (P < .01) and respiratory morbidity (P < .01) as well as fetal hydrops (P < .01) and bilateral effusion (P = .01).

CONCLUSIONS

Fetal total lung volumes may be useful for the prediction of perinatal outcomes in primary pleural effusion.

Assessment of lung volume by 3-dimensional sonography and magnetic resonance imaging in fetuses with congenital diaphragmatic hernias

OBJECTIVES

The purpose of this study was to evaluate the influence of different rotation angles in assessment of the contralateral lung volume by 3-dimensional (3D) sonography in comparison to magnetic resonance imaging (MRI) in fetuses with congenital diaphragmatic hernias.

METHODS

A total of 126 measurements by 3D sonography and MRI were conducted in 81 patients between 18 and 39 weeks' gestation. The 3D sonographic volumes of the contralateral fetal lung were calculated by the rotational technique (virtual organ computer-aided analysis) with rotation angles of 6°, 15°, and 30°. Transverse multiplanar T2-weighted MRI was performed for the MRI measurements. To compare the accuracy of 3D sonographic volumetry using different rotation angles, MRI assessment was taken as the reference method, and percentage errors and limits of agreement were calculated for each angle.

RESULTS

Three-dimensional sonographic volume measurements showed a high correlation with MRI (6° angle, R(2) = 0.86; 15° angle, R(2) = 0.78; 30° angle, R(2) = 0.68). The mean percentage error showed no systematic error. With regard to random error, the 6° step had significantly lower values than the larger angles 30° step (R = 0.472) and the narrowest limits of agreement.

CONCLUSIONS

Especially when using a small rotation angle, assessment of the contralateral fetal lung volume by 3D sonography in congenital diaphragmatic hernias is a reliable alternative to MRI.

In vitro models of the fetal lung: comparison of lung volume measurements with 3-dimensional sonography and magnetic resonance imaging

OBJECTIVES

Three-dimensional (3D) sonography is an established volumetric method in gynecology and obstetrics. The aim of this study was to investigate the variability of 3D sonographic measurements and their accuracy in comparison with magnetic resonance imaging (MRI) for assessing fetal lung volume using in vitro lung models.

METHODS

Twenty-three in vitro lung models with randomly defined volumes ranging from 1 to 60 mL were made from gelatin with plastic sheaths, manually molded into the shape of fetal lungs. The models were measured using 3D sonography and MRI. The 3D sonographic volumes were calculated using the rotational technique with angles of 6° and 30°. Multiplanar T2-weighted sequences were used for the MRI measurements. The percentage error and absolute percentage error were calculated for each method, and intraobserver and interobserver variability in 3D sonographic measurements was assessed with intraclass correlation coefficients (ICCs). Agreement between calculated and real volumes using the limits of agreement method was also evaluated.

RESULTS

The ICCs for the rotation angles indicated very good intraobserver and interobserver variability (6°, 0.995 and 0.996; 30°, 0.997 and 0.985). No systematic errors were observed in the mean percentage errors for 3D sonographic measurements or MRI volumetry. The lowest median absolute percentage error (1.76) was obtained with MRI volumetry, significantly lower than the values for sonography (6°, 5.00; P < .001; 30°, 5.49; P < .001). There were no significant differences in absolute percentage errors between the rotation angles (P = .82) and no significant differences in limits of agreement between 3D sonography and MRI (6°, P = .76; 30°, P = .39).

CONCLUSIONS

Three-dimensional sonographic volumetry was almost as accurate as MRI in this in vitro model and can be regarded as a good alternative method. Further research is needed to confirm these findings in vivo and to assess the prognostic value in fetuses with lung hypoplasia (eg, congenital diaphragmatic hernias).

Influence of different rotation angles in assessment of lung volumes by 3-dimensional sonography in comparison to magnetic resonance imaging in healthy fetuses

OBJECTIVES

Three-dimensional (3D) sonographic volumetry is established in gynecology and obstetrics. Assessment of the fetal lung volume by magnetic resonance imaging (MRI) in congenital diaphragmatic hernias has become a routine examination. In vitro studies have shown a good correlation between 3D sonographic measurements and MRI. The aim of this study was to compare the lung volumes of healthy fetuses assessed by 3D sonography to MRI measurements and to investigate the impact of different rotation angles.

METHODS

A total of 126 fetuses between 20 and 40 weeks' gestation were measured by 3D sonography, and 27 of them were also assessed by MRI. The sonographic volumes were calculated by the rotational technique (virtual organ computer-aided analysis) with rotation angles of 6° and 30°. To evaluate the accuracy of 3D sonographic volumetry, percentage error and absolute percentage error values were calculated using MRI volumes as reference points. Formulas to calculate total, right, and left fetal lung volumes according to gestational age and biometric parameters were derived by stepwise regression analysis.

RESULTS

Three-dimensional sonographic volumetry showed a high correlation compared to MRI (6° angle, R(2) = 0.971; 30° angle, R(2) = 0.917) with no systematic error for the 6° angle. Moreover, using the 6° rotation angle, the median absolute percentage error was significantly lower compared to the 30° angle (P < .001). The new formulas to calculate total lung volume in healthy fetuses only included gestational age and no biometric parameters (R(2) = 0.853).

CONCLUSIONS

Three-dimensional sonographic volumetry of lung volumes in healthy fetuses showed a good correlation with MRI. We recommend using an angle of 6° because it assessed the lung volume more accurately. The specifically designed equations help estimate lung volumes in healthy fetuses.

Three-dimensional ultrasound fetal lung volumes and infant respiratory outcome: a prospective observational study

OBJECTIVE

To determine if fetal lung volumes (FLVs), determined by three-dimensional rotational ultrasound and virtual organ computer-aided analysis software (vocal), correlated with neonatal respiratory outcomes in surviving infants who had a high risk [fetuses with congenital diaphragmatic hernia (CDH)], lower risk [fetuses with anterior wall defects (AWDs)] and no risk (controls) of abnormal antenatal lung growth.

DESIGN

Prospective observational study.

SETTING

Tertiary fetal medicine and neonatal intensive care units.

POPULATION

Sixty fetuses (25 with CDH, 25 with AWDs and ten controls).

METHODS

FLVs were measured and expressed as the percentage of the observed compared with the expected for gestational age.

MAIN OUTCOME MEASURES

Neonatal respiratory outcome was determined by the duration of supplemental oxygen, mechanical ventilation and dependencies, and assessment of lung volume using a gas dilution technique to measure functional residual capacity (FRC).

RESULTS

The infants with CDH had lower FLV results than both the infants with AWDs (P=0.05) and the controls (P<0.05). The infants with CDH had longer durations of mechanical ventilation (P<0.001) and supplementary oxygen (P<0.001) dependence, compared with infants with AWDs. The infants with CDH had a lower median FRC than both the infants with AWDs (P<0.001) and the controls (P<0.001). FLV results correlated significantly with the durations of dependency on ventilation (r= -0.744, P<0.01) and oxygen (r= -0.788, P<0.001), and with FRC results (r=0.429, P=0.001).

CONCLUSIONS

These results suggest that FLVs obtained using three-dimensional rotational ultrasound might be useful in predicting neonatal respiratory outcome in surviving infants who had varying risks of abnormal lung growth. Larger and more comprehensive studies are needed to clarify the role that lung volume measurements have in assessing lung function and growth.

Reproducibility of fetal heart volume by 3D-sonography using the XI VOCAL method

Background

To assess the reliability of fetal heart volume measurement by three-dimensional sonography (3DUS) using the eXtended Imaging Virtual Organ Computer-aided AnaLysis (XI VOCAL) method.

Methods

This reliability study enrolled 30 pregnant women with singleton healthy pregnancies between 19 and 34 weeks of gestation. All volume acquirements were performed with a convex volumetric transducer (C3-7ED) coupled to an Accuvix XQ sonography device (Medison, Korea). The XI VOCAL 10 planes was the method of choice for volumetric measurement. 3D datasets were analyzed by two observers (EQSB and HJFM); fetal heart volume was measured twice by the first and once by the second observer to calculate intra and interobserver reproducibility. Statistical analysis used pareated Student's t test (p) and calculated Intraclass correlation coefficients (ICC). Bland-Altman plots were also constructed.

Results

We observed an excellent intra- and interobserver reliability for fetal cardiac volume assessed by XI VOCAL. For the intraobserver the ICC was 0.998 (95% CI: 0.997; 0.999), with mean of differences of 0.12 cm³ (95% limits of agreement: -0.84; +0.84; p = 0.130). For interobserver the ICC was 0.899 (95%CI: 0.996; 0.998), mean of differences 0.05 cm³ (95% limits of agreement: -0.84; +0.84; p = 0.175).

Conclusion

Fetal cardiac volume assessed by 3DUS using XI VOCAL method is highly reproducible between 19 to 34 gestational weeks.

Fetal lung volume in fetuses with urinary tract malformations: comparison by 2D-, 3D-sonography and magnetic resonance imaging

OBJECTIVE

To evaluate the concordance between two-dimensional ultrasonography (2DUS), three-dimensional ultrasonography (3DUS) and magnetic resonance imaging (MRI) in the assessment of lung volume in fetuses with urinary tract malformations (UTM).

METHODS

This was a cross-sectional study involving 12 pregnancies between 19 and 34 weeks, with various fetal UTM. Pulmonary volume was obtained by 2DUS using the following equation: total lung volume = [right lung antero-posterior diameter (X) x transverse diameter (Y) x cranial-caudal diameter x 0.152 + left lung (X1) x (Y1) x (Z1) x 0.167]. Pulmonary volume by 3DUS was obtained using the virtual organ computer-aided analysis (VOCAL) method with a 30 degrees (VOL30), 18 degrees (VOL18) and 12 degrees (VOL12) rotation. A fast sequence of transverse lung section was also obtained by MRI. The intraclass correlation coefficient was used to evaluate the correlation between the three methods. The paired student t-test was used to compare the means.

RESULTS

There was a strong correlation between the three methods, and the highest correlations were between MRI and VOL18 for the right (ICC = 0.913) and left (ICC = 0.947) lungs. A strong correlation was also found between the lung volumes obtained through MRI and VOL12 as well as VOL18 (p = 0.544 and 0.286, respectively). However, for the left lung there was only a correlation between MRI and VOL12 (p = 0.49).

CONCLUSIONS

There is a good concordance between 3DUS (VOL12) and MRI in the evaluation of lung volume in fetuses with UTM.

Reference range of fetal lung volume by 3D-ultrasonography using the rotational method (VOCAL)

AIM

To determine reference ranges for fetal lung volume by 3-dimensional ultrasonography using the VOCAL (Virtual Organ Computed-aided Analysis) method.

METHODS

A longitudinal prospective study was conducted with 61 uncomplicated pregnancies between 24 and 32 weeks of gestation. A separate measurement of both lungs volume was conducted by VOCAL with 30 degrees rotation angle. For each gestational age, an average, standard deviation and maximal and minimal values were established in addition to the percentiles 5, 10, 25, 50, 75 and 90 for right and left lung volume. To evaluate the correlation between lung volume and gestational age, and estimated fetal weight, a polynomial regression with determination coefficient adjustment (R(2)) was used. The intra-observer reproducibility was evaluated by the intraclass correlation coefficient (ICC), whereas the inter-observer reproducibility was evaluated by Cronbach alpha statistic test.

RESULTS

The average right lung volume varied from 12.5+/-0.7 cm(3) at the 24(th) week to 31.8 cm(3)+/-1.8 cm(3) at the 32(nd) week. The average left lung volume varied from 9.2+/-0.9 cm(3) at the 24(th) week to 22.0 cm(3)+/-1.6 cm(3) at the 32(nd) week. We observed a strong correlation between right lung volume and gestational age (R(2)=0.975) and estimated fetal weight (R(2)=0.905), as well as between the left lung volume with gestational age (R(2)=0.970) and estimated fetal weight (R(2)=0.908). We observed a good intra-observer reproducibility for the right lung volume (ICC=0.990) and for the left lung volume (ICC=0.986). Similarly, we observed good inter-observer reproducibility for right lung volume (0.975) and left lung volume (0.962).

CONCLUSION

Reference range of fetal lung volume by 3D-ultrasonography using the VOCAL method was determined.

Three- and four-dimensional ultrasound: new methods for evaluating fetal thoracic anomalies

OBJECTIVE

To study three- (3D) and four-dimensional (4D) ultrasound applications for the evaluation of fetal thoracic anomalies.

METHODS

Volume datasets of 23 fetuses with thoracic anomalies were acquired with static 3D and cine 4D ultrasound, i.e. spatiotemporal image correlation (STIC) mode. The volumes were analyzed and displayed by multiplanar and tomographic ultrasound imaging (TUI) modes and static volume contrast imaging (VCI). Color Doppler was added to the volumes acquired, and various rendering modes were used to display the volume datasets.

RESULTS

The mean gestational age at evaluation was 22 (range, 14-34) weeks. The anomalies were identified as: diaphragmatic hernia (n = 5), lung dysplasia (n = 11), skeletal dysplasia with small thorax/thanatophoric dysplasia (n = 2), abnormal situs (n = 2), hydrothorax (n = 2) and esophageal atresia (n = 1). The TUI mode achieved optimal display of the thorax, thereby aiding the diagnosis of diaphragmatic hernia and lung dysplasia. In right diaphragmatic hernias, the VCI mode proved invaluable as it distinguished liver from lung tissue. High-definition color Doppler with glass-body rendering significantly contributed to the detection of abnormal vascularization in lung dysplasia. Maximal transparent mode with a transvaginal transducer provided accurate diagnosis of skeletal dysplasia in the first trimester. Situs abnormalities were best viewed with a minimal transparent mode, in which abnormal organs and positions of vessels were clearly identified. Pleuroamniotic shunt localization was monitored precisely by 3D in a fetus with hydrothorax, and inversion mode added important information regarding the size of an esophageal pouch in a fetus with esophageal atresia.

CONCLUSION

The 3D-4D technique is a novel, useful sonographic tool for evaluating the fetal thorax. It enhances precise diagnosis and provides better spatial visualization of the anomalies involved.

Three-dimensional sonographic measurement of contralateral lung volume in fetuses with isolated congenital diaphragmatic hernia

PURPOSE

To use 3-dimensional sonography (3DUS) to measure contralateral lung volume and evaluate the potential of this measurement to predict neonatal outcome in isolated congenital diaphragmatic hernia (CDH).

METHODS

Between January 2002 and December 2004, the contralateral lung volumes of 39 fetuses with isolated CDH were measured via 3DUS using rotational multiplanar imaging. The observed/expected contralateral fetal lung volume ratios (o/e-ContFLVR) were compared with the lung/head ratio (LHR), observed/expected total fetal lung volume ratio (o/e-TotFLVR), and postnatal outcome.

RESULTS

Contralateral lung volumes are less reduced than total lung volumes in CDH. The bias and precision of 3DUS in estimating contralateral lung volumes were 0.99 cm(3) and 1.11 cm(3), respectively, with absolute limits of agreement ranging from -1.19 cm(3) to +3.17 cm(3). The o/e-ContFLVR was significantly lower in neonatal death cases (median, 0.49 cm(3); range, 0.22-0.99 cm(3)) than in survival cases (median, 0.58 cm(3); range, 0.42-0.92 cm(3) [p < 0.01]). Overall accuracy of the o/e-ContFLVR, o/e-TotFLVR, and LHR in predicting neonatal death were 67.7% (21/31), 80.7% (25/31), and 77.4% (24/31), respectively.

CONCLUSION

Although o/e-ContFLVR can be precisely measured with 3DUS and can be used to predict neonatal death in CDH, it is less accurate than LHR and o/e-TotFLVR for that purpose.

Predicting perinatal outcome in isolated congenital diaphragmatic hernia using fetal pulmonary artery diameters

OBJECTIVE

The aim of the study was to evaluate the potential of fetal pulmonary artery (PA) diameters to predict perinatal death and pulmonary arterial hypertension (PAH) in congenital diaphragmatic hernia (CDH).

STUDY DESIGN

In this prospective observational study, observed PA (main, right, and left) diameters were measured at the level of the 3 vessels in 21 fetuses with isolated CDH and in 85 controls at 22 to 36 weeks. The observed/expected (o/e) diameters of the main, contralateral, and ipsilateral PAs were calculated by comparing these measurements with reference values obtained in our previous study and correlated with perinatal death and postnatal PAH.

RESULTS

The o/e PA diameters were significantly reduced in fetuses with CDH compared to controls (P < .001) and in fetuses with CDH who died (P < .050). However, there was no significant association between PA diameters and PAH (P >or= .050).

CONCLUSIONS

The PA diameters might be useful to predict perinatal death in isolated CDH but not postnatal PAH, suggesting that PA diameters are probably related to the severity of pulmonary hypoplasia.

Congenital diaphragmatic hernia

The incidence of congenital diaphragmatic hernia (CDH) may be as high as 1 in 2000. Over the past two decades, antenatal diagnosis rates have increased, the pathophysiology of CDH has become better understood, and advances in clinical care, including foetal surgery, have occurred. However, there remains a paucity of randomised controlled trials to provide evidence-based management guidelines. Reports of improved survival rates appear to be confined to a select subset of CDH infants, surviving to surgical repair, while the overall mortality, at over 60%, appears to be unchanged, largely due to the often forgotten 'hidden mortality' of CDH. The significant long-term morbidity in surviving infants has become apparent, and the need for long-term multidisciplinary follow up established. A total of 10% of cases may present later in life, and misdiagnosis on initial chest X-ray may lead to significant morbidity.

Pulmonary artery diameters in healthy fetuses from 19 to 40 weeks' gestation

OBJECTIVE

The purpose of this study was to construct nomograms for diameters of the fetal main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA) according to gestational age (GA) and estimated fetal weight (EFW).

METHODS

Between May 2005 and February 2006, MPA and branch artery diameters were prospectively estimated with ultrasonography in 220 healthy fetuses from 19 to 40 weeks' gestation and correlated with GA and EFW.

RESULTS

Mean MPA, RPA, and LPA diameters ranged from 2.93, 1.71, and 1.66 mm, respectively, at 19 weeks to 9.23, 5.49, and 5.65 mm at 40 weeks. Linear regression yielded the following formulas for the expected diameters according to GA: MPA=-2.77 + 0.30 x GA; RPA=-1.71 + 0.18 x GA; and LPA=-1.95 + 0.19 x GA. The following formulas were obtained by logarithm distribution for the expected diameters according to EFW: MPA=-1.165 + 0.247 x log of estimated fetal weight (lnFW); RPA=-0.651 + 0.141 x lnFW; and LPA=-0.718 + 0.150 x lnFW.

CONCLUSIONS

Nomograms of MPA and branch pulmonary artery diameters according to GA and EFW have been described, generating reference values.

T2 quantifications of lungs in the fetal lamb with experimentally-induced congenital diaphragmatic hernia

OBJECTIVE

As an aid to evaluate lung hypoplasia, we investigated the difference between T2 value in fetal lungs of lambs with surgically-induced left-sided diaphragmatic hernia (DH) and gestational age (GA)-matched control littermates (normal [NL]).

METHODS

Lungs were divided into two groups: DH (n = 4) and NL (n = 6). DH was induced at 65-75 days GA (term = 145 days). Fetal MRI was performed (mean GA: 120 days) with half-Fourier acquisition single-shot turbo spin-echo (TE: 60 ms) and rapid acquisition with relaxation enhancement (TE: 350 ms) in the same location (1.5-T Philips, Gyroscan, Best, The Netherlands). T2 of each lung was calculated for multiple regions of interest by taking natural logarithm of signal-to-noise ratio. Mean T2 was compared between DH and NL (unpaired analysis for entire group). Paired comparison between left/right lung was made within DH and NL.

RESULTS

Unpaired analysis showed significantly lower T2 of left respectively right lungs in DH (p = 0.02 [respectively] 0.05]) compared to NL (n = 6), as well as between the T2 of all DH versus NL (p = 0.001). In DH, calculated T2 appeared to be lower in left than in right lungs (difference ranged from -2 to +49%). In NL, left and right lungs showed comparable T2.

CONCLUSION

Measurement of T2 signal intensity in DH lungs is feasible and show lower T2 in comparison to NL lungs. Left lungs from lambs with DH show lower T2 than right lungs.

Quantitative analysis of fetal pulmonary vasculature by 3-dimensional power Doppler ultrasonography in isolated congenital diaphragmatic hernia

OBJECTIVE

The purpose of this study was to evaluate the potential of 3-dimensional (3D) power Doppler imaging to predict neonatal outcome and pulmonary arterial hypertension (PAH) in congenital diaphragmatic hernia (CDH).

STUDY DESIGN

In this prospective observational study, 3D-power Doppler ultrasonography was performed in 21 cases with isolated CDH between 23 and 33 weeks of gestation and in 58 controls between 20 and 40 weeks. Using the same preestablished settings for all cases, power Doppler was applied to each lung, and fetal lung volumes (FLV) were estimated using the rotational technique. The 3D power Doppler histogram was used to determine the vascular indices, which were plotted against gestational age and compared with neonatal outcome, PAH, gestational age, and FLV.

RESULTS

Fetal pulmonary vascular indices showed a constant distribution throughout gestation, being significantly lower in cases with CDH than in controls (P < .001). Among CDH cases, the vascular indices were significantly lower in fetuses who died (P < .05), and in fetuses with neonatal PAH (P < .05). The severity of neonatal PAH was also associated with a progressive reduction in prenatal vascular indices (P < .05). All vascular indices correlated with o/e-FLV, but not with gestational age.

CONCLUSION

All vascular indices seem to be constant throughout gestation. In isolated CDH, perinatal outcome and postnatal PAH can be predicted using the vascular indices assessed by 3D power Doppler histogram.

Predicting pulmonary hypoplasia using the sonographic fetal lung volume to body weight ratio--how precise and accurate is it?

OBJECTIVES

To determine the precision and accuracy of ultrasound in estimating the fetal lung to body weight ratio (FLB ratio) using two-dimensional (2D) and three-dimensional (3D) ultrasound by comparison with postmortem measurements, and to evaluate its potential to diagnose pulmonary hypoplasia.

METHODS

Lung volumes were estimated by 3D ultrasound (rotational technique) and fetal weights were measured by 2D ultrasound (Hadlock equation) in 35 fetuses immediately before termination of pregnancy at 15-38 weeks. Sonographic estimates of FLB ratio were compared with postmortem values. Based on the pathological definition of pulmonary hypoplasia, the accuracy of sonographic estimation of the FLB ratio was analyzed.

RESULTS

The mean gestational age at termination of pregnancy was 26.7 (range, 15-38) weeks. The mean FLB ratios were 0.018 (SD, 0.006) on ultrasound and 0.019 (SD, 0.007) at autopsy (P = 0.730). Bias and precision of sonographic FLB ratio were - 0.001 and 0.003 (absolute limits, - 0.007 to + 0.006), respectively. Pulmonary hypoplasia was diagnosed in 12 (34.3%) cases at autopsy. The sonographic FLB ratio was significantly lower in fetuses with pulmonary hypoplasia at autopsy (median, 0.011; range, 0.004-0.014) than it was in those without pulmonary hypoplasia (median, 0.022; range, 0.013-0.045, P < 0.001). The sensitivity and specificity of the sonographic FLB ratio for diagnosing pulmonary hypoplasia were 91.7% (11/12) and 91.3% (21/23), respectively, the positive and negative predictive values were 84.6% (11/13) and 95.5% (21/22), and the accuracy was 91.4% (32/35).

CONCLUSION

FLB ratio can be estimated precisely on ultrasound examination, albeit with wide limits of agreement. The sonographically estimated FLB ratio may be useful in the prediction and diagnosis of pulmonary hypoplasia.

Prenatal diagnosis and perinatal outcome of 38 cases with congenital diaphragmatic hernia: 8-year experience of a tertiary Brazilian center

PURPOSE

To evaluate the perinatal results for neonates with congenital diaphragmatic hernia diagnosed prenatally.

METHOD

We reviewed data from 38 cases of congenital diaphragmatic hernia diagnosed prenatally from January 1995 to December 2003 in the Fetal Medicine Unit of the Department of Obstetrics and Gynecology, São Paulo University Medical School. The main data analyzed were gestational age at diagnosis, fetal karyotyping, side of diaphragmatic defect, presence of associated structural malformations, hepatic herniation, and severe mediastinal shift. Perinatal outcomes were obtained by reviewing hospital documents or by directly calling the patients' immediate relatives.

RESULTS

Mean gestational age at diagnosis was 29 weeks (range, 16-37 weeks). Thirty (79%) cases had a left diaphragmatic defect and 8 (21%) had a right lesion. Associated structural malformations were observed in 21 (55%) cases, in which 12 fetuses had a normal karyotype and 9 had chromosomal abnormalities. Isolated congenital diaphragmatic hernia was confirmed in 17 (45%) cases. The overall perinatal mortality rate was 92%. Rates of fetal deaths, early neonatal deaths, late neonatal deaths, and survival were 42%, 50%, 0%, and 8%, respectively, in cases with associated structural malformations but normal karyotyping; 56%, 44%, 0%, and 0% for cases with chromosomal abnormalities; and, 0%, 76%, 12%, and 12% in cases with isolated congenital diaphragmatic hernia. The neonatal mortality rate was 89% in cases with isolated congenital diaphragmatic hernia.

CONCLUSION

Perinatal mortality was very high in prenatally diagnosed cases of congenital diaphragmatic hernia. Earlier perinatal deaths are associated with the presence of other structural defects or chromosomal abnormalities. In cases of isolated congenital diaphragmatic hernia, mortality is related to the presence of herniated liver, right-sided lesion, and major mediastinal shift.

A nomogram of fetal lung volumes estimated by 3-dimensional ultrasonography using the rotational technique (virtual organ computer-aided analysis)

OBJECTIVE

The purpose of this study was to build a nomogram of normal fetal lung volumes throughout gestational age estimated by 3-dimensional ultrasonography using the rotational technique (Virtual Organ Computer-Aided Analysis [VOCAL]; GE Healthcare, Kretztechnik, Zipf, Austria).

METHODS

Fetal lung volume was assessed in 146 healthy fetuses by 3-dimensional ultrasonography using the technique of rotation of the multiplanar imaging (VOCAL). Inclusion criteria were healthy women with singleton normal pregnancies, normal fetal morphologic ultrasonographic findings, reliable dating established by dates and by ultrasonographic measurement of the crown-lump length in the first trimester, and gestational age from 20 to 37 weeks. Exclusion criteria were discordance between clinical and ultrasonographic dating, patients lost to follow-up, and birth weight disorders. Each patient was scanned once during pregnancy.

RESULTS

The right, left, and total mean pulmonary volumes ranged, respectively, from 5.37, 4.66, and 9.95 cm3 at 20 weeks to 46.06, 37.34, and 84.35 cm3 at 37 weeks. The logistic transformation analysis yielded the following formulas: right lung volume = exp(4.07/[1 + exp(21.90 - gestational age/5.44)]); left lung volume = exp(3.82/(1 + exp[22.03 - gestational age/5.17)]); and, total lung volume = exp(4.72/[1 + exp(20.30 - gestational age/6.05)]).

CONCLUSIONS

A new nomogram of fetal lung (right, left, and total) volumes throughout gestational age using the rotational technique (VOCAL) is described, and reference values have been generated.

Left and right lung volumes in fetuses with diaphragmatic hernia

OBJECTIVE

To compare the volume of the ipsilateral and contralateral lungs in fetuses with congenital diaphragmatic hernia (CDH).

METHODS

Left and right lung volumes were measured using three-dimensional (3D) ultrasonography in 42 fetuses with CDH at median 26 (range, 20-32) weeks of gestation. Each value was then expressed as a difference, in standard deviations, from the normal mean for gestation, previously established from the study of 650 normal fetuses at 12-32 weeks (Z-score). The Mann-Whitney U-test was used to determine the significance of the differences between the measurements in fetuses with CDH and normal fetuses and between the ipsilateral and contralateral lungs in fetuses with left- and right-sided CDH.

RESULTS

There were 34 fetuses with left-sided CDH and eight with right-sided CDH. In CDH both the ipsilateral and contralateral lung volumes were substantially lower than in normal fetuses. In left CDH the left lung volume was 4.03 (median; range, 3.11-4.78) SDs below the normal mean for gestation, and the respective values for the right lung were 3.04 (median; range, 1.78-4.31) SDs (P < 0.001 for both). In right CDH, the left lung volume was 2.91 (median; range, 1.62-4.07) SDs below the normal mean for gestation and the respective values for the right lung were 4.35 (median; range, 3.07-4.99) SDs (P < 0.001 for both). In both left and right diaphragmatic hernia the deficit in the volume of the ipsilateral lung was significantly greater than the deficit in the contralateral lung.

CONCLUSIONS

In fetuses with CDH both the ipsilateral and contralateral lung volumes are substantially lower than in normal fetuses.

Three- and 4-dimensional ultrasound in obstetric practice: does it help?

OBJECTIVE

The purpose of this article was to review the published literature on 3-dimensional ultrasound (3DUS) and 4-dimensional ultrasound (4DUS) in obstetrics and determine whether 3DUS adds diagnostic information to what is currently provided by 2-dimensional ultrasound (2DUS) and, if so, in what areas.

METHODS

A PubMed search was conducted for articles reporting on the use of 3DUS or 4DUS in obstetrics. Seven-hundred six articles were identified, and among those, 525 were actually related to the subject of this review. Articles describing technical developments, clinical studies, reviews, editorials, and studies on fetal behavior or maternal-fetal bonding were reviewed.

RESULTS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, especially facial clefts. There is also evidence that 3DUS provides additional diagnostic information in neural tube defects and skeletal malformations. Large studies comparing 2DUS and 3DUS for the diagnosis of congenital anomalies have not provided conclusive results. Preliminary evidence suggests that sonographic tomography may decrease the examination time of the obstetric ultrasound examination, with minimal impact on the visualization rates of anatomic structures.

CONCLUSIONS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical role of 3DUS and 4DUS for the diagnosis of congenital heart disease and central nervous system anomalies. Future studies should determine whether the information contained in the volume data set, by itself, is sufficient to evaluate fetal biometric measurements and diagnose congenital anomalies.

Prenatal prognosis of congenital diaphragmatic hernia using magnetic resonance imaging measurement of fetal lung volume

OBJECTIVES

To investigate the correlation between fetal lung volume (FLV), measured with magnetic resonance imaging (MRI), and postnatal mortality in newborns with prenatally diagnosed isolated congenital diaphragmatic hernia (CDH).

METHODS

In a 4-year prospective multicenter study, 77 fetuses with isolated CDH diagnosed between 20 and 33 weeks' gestation underwent fast spin-echo T2-weighted lung MRI. These MRI-FLV measurements were compared with a previously published normative curve obtained in 215 fetuses without thoracoabdominal malformations and with normal ultrasound biometric findings. FLV measurements were correlated with postnatal survival. The mean gestational age at MRI was 31.3 weeks.

RESULTS

The measured/expected FLV ratio was significantly lower in the newborns with CDH who died compared with those who survived (23.6 +/- 12.2 vs. 36.1 +/- 13.0, P < 0.001). When the ratio was below 25%, there was a significant decrease in postnatal survival (19% vs. 40.3%, P = 0.008). Survival was significantly lower for neonates when one lung could not be seen by fetal MRI compared with those fetuses with two visible lungs on MRI (17.9% vs. 62.1%, P < 0.001).

CONCLUSION

In isolated CDH, FLV measurement by MRI is a good predictor of postnatal mortality due to pulmonary hypoplasia.

Accuracy of fetal lung volume assessed by three-dimensional sonography

OBJECTIVE

To determine the accuracy and precision of prenatal three-dimensional (3D) ultrasound in estimating fetal lung volume using the rotational multiplanar technique (VOCAL) by comparing it to postmortem volume measurements.

METHODS

Fetal lung volume was measured during 3D ultrasound examination using a rotational multiplanar technique in eight cases of congenital diaphragmatic hernia (CDH) (six left and two right-sided) and in 25 controls without pulmonary malformation, immediately before termination. Prenatal 3D sonographic estimates of fetal lung volume were compared with postmortem measurement of fetal lung volume achieved by water displacement.

RESULTS

The intraclass correlation coefficient of fetal lung volume estimated by 3D ultrasound and measured at postmortem examination was 0.95 in CDH cases and 0.99 in controls. Based on Bland-Altman analysis, the bias, precision and limits of agreement were, respectively, 0.35 cm(3), 1.46 cm(3) and between -2.51 and + 3.21 cm(3) in cases with CDH and 0.08 cm(3), 2.80 cm(3) and between -5.41 and + 5.57 cm(3) in controls. The mean relative error of 3D ultrasound fetal lung volume measurement was -7.19% (from -42.70% to + 18.11%) in CDH cases and -0.72% (from -30.25% to + 19.22%) in controls, while the mean absolute error of 3D ultrasound fetal lung volume measurement was 1.40 (range, 0.71-2.52) cm(3) and 2.12 (range, 0.05-4.98) cm(3), respectively. Accuracy of 3D ultrasound for measuring fetal lung volumes was 84.86 (range, 57.30-99.48)% in cases with CDH and 91.38 (range, 69.75-99.45)% in controls. The mean intraobserver variability for lung volume estimated by 3D ultrasound was 0.28 cm(3) in controls and 0.17 cm(3) in CDH cases.

CONCLUSION

Prenatal 3D ultrasound can estimate accurately fetal lung volume using the rotational multiplanar technique for volume measurements (VOCAL), even in fetuses with very small lungs, such as cases with isolated CDH.

Antenatal diagnosis of congenital diaphragmatic hernia

Congenital diaphragmatic hernia occurs in approximately 1 of 2200 live births and is associated with a high degree of morbidity and mortality. Poor outcome in these cases is primarily related to the presence of additional anomalies or abnormal karyotype and the development of pulmonary and cardiovascular complications. Prenatal diagnosis occurs in approximately 50% of cases. Multiple ultrasound markers have been identified as being predictive of outcome. Three-dimensional ultrasound, fetal echocardiography, and magnetic resonance imaging have been identified as additional imaging modalities that can assist in making the antenatal diagnosis and accurately assessing perinatal outcome.

Fetal lung volumetry using two- and three-dimensional ultrasound

OBJECTIVES

To compare methods of measuring fetal pulmonary volume and to establish nomograms of fetal pulmonary volume according to gestational age for the accurate diagnosis of pulmonary hypoplasia.

METHODS

Three methods of measuring fetal pulmonary volume in 39 normal fetuses were compared: two-dimensional (2D) ultrasound measurement assuming that the lung is a geometrical pyramid, three-dimensional (3D) ultrasound using the VOCAL rotational method, and the conventional multiplanar 3D mode. Linear regression was used to construct an equation for 3D volume calculation from 2D measurements (the re-evaluated pulmonary volume equation (RPVE)). Lung volume measurements were recorded from 622 singleton fetuses in order to construct nomograms.

RESULTS

There was no statistically significant difference between the lung volume values obtained using the two 3D modes. However, in comparison with the 2D measurements the volumes obtained were larger (mean difference = 11.99, P < 0.1 x 10(-6)). The relationship between the 2D and 3D volumes was determined using a statistical linear regression method: RPVE (mL) = 4.24 + (1.53 x 2DGPV), where 2DGPV (2D geometric pulmonary volume) = (surface area right lung base (cm2) + surface area left lung base (cm2)) x 1/3 height right lung (cm). Two nomograms were constructed, one for use with 2D and one for 3D technology.

CONCLUSION

2D pulmonary volume assessment can be used in clinical situations where fetal prognosis depends on lung volume and its growth potential. It is routinely available and easy to perform particularly when repeat measurements are required in evaluation of lung growth. We therefore propose this method as an alternative to magnetic resonance imaging or 3D ultrasound.

Fetal lung volume estimated by 3-dimensional ultrasonography and magnetic resonance imaging in cases with isolated congenital diaphragmatic hernia

OBJECTIVE

To assess the agreement of 3-dimensional ultrasonography and magnetic resonance imaging in estimating fetal lung volume in cases with isolated congenital diaphragmatic hernia.

METHODS

Fetal lung volume was measured in 11 cases of congenital diaphragmatic hernia (10 left and 1 right) by 3-dimensional ultrasonography and magnetic resonance imaging. These examinations were performed during the same week. The operators were blinded to each other's results. Intraclass correlation was used to evaluate the agreement between 3-dimensional ultrasonography and magnetic resonance imaging estimations of the ipsilateral, contralateral, and total fetal lung volume. A Bland-Altman graph was plotted to detect possible discordant observations.

RESULTS

The global intraclass correlation coefficient between magnetic resonance imaging and 3-dimensional ultrasonographic measurement of fetal lung volume was 0.94 (95% confidence interval, 0.78-0.98) with no outliers observed on the Bland-Altman plot.

CONCLUSIONS

There is a good agreement between 3-dimensional ultrasonography and magnetic resonance imaging for fetal lung volume estimation in cases with congenital diaphragmatic hernia.