Three-dimensional sonographic volume measurement of the fetal lung

AIM: The objective of this longitudinal study was to evaluate the growth of the fetal lung in normal pregnancies, using 3-D ultrasound. METHODS: 3-D sonographic examinations were performed on 14 appropriate-for-gestational-age fetuses. Fetal lung volumes (left, right, and total lung volumes) were measured every 2-3 weeks from 20 weeks of gestational age until delivery. The common multiplanar technique was used to calculate fetal lung volume. RESULTS: Curvilinear relationships were found between the gestational age and left (R2 = 86.9%, P < 0.0001), right (R2 = 83.9%, P < 0.0001) and total (R2 = 83.8%, P < 0.0001) lung volumes. The data described in this study were fairly comparable with previous data from autopsy series. However, there were big differences for predicted values of the fetal total lung volumes using 3-D ultrasound among the present study and previous investigations. CONCLUSION: Our findings suggest that the standard curve for fetal lung volume using 3-D ultrasound provides a role for evaluating the normal lung growth in the fetus. However, we do cast doubt on the reliability and reproducibility of fetal lung volume measurements using 3-D ultrasound. Moreover, the data and its interpretation in our study should be taken with some degree of caution because of the small number of subjects studied. Further studies involving a larger sample size would be needed to confirm these findings.     

Three-dimensional sonographic measurement of normal fetal brain volume during the second half of pregnancy

OBJECTIVES: This study was undertaken to develop a three-dimensional (3D) ultrasound method of measuring fetal brain volume. STUDY DESIGN: Serial 3D sonographic measurements of fetal brain volume were made in 68 normal singleton pregnancies at 18 to 34 weeks of gestation. A comparison was made with fetal brain volume estimates from two-dimensional (2D) sonographic measurement of head circumference and published postmortem fetal brain weights. RESULTS: Coefficient of variation for fetal brain volume (3D) caused by differences between repeated tests was 10.2% and between analyses of the same recorded volume 2.2%. Median brain volume increases from 34 mL at 18 weeks to 316 mL at 34 weeks. Median brain weight represented approximately 15% of total fetal weight. The 3D ultrasound-derived brain weight is larger than postmortem brain weight. However, this is not so for brain weight derived from total fetal weight at autopsy. A good agreement between 3D and 2D brain volume was found. CONCLUSION: Sonographic measurement of fetal brain volume demonstrated an acceptable intraobserver variability and a nearly 10-fold increase during the second half of gestation.     

Three-dimensional ultrasound fetal urinary bladder volume measurement: reliability of rotational (VOCAL) technique using different steps of rotation

Objective The aim of the study was to investigate the inter- and intraobserver reliability in measuring the fetal bladder volume by 3d ultrasound imaging by VOCAL^TM. In addition a comparison of 15° and 30° rotation steps calculation had been performed. Methods Measurements (n = 240) of FB volume were performed in 30 low-risk patients with gestation times ranging from 22 to 39 weeks by two independent observers blind to each other. All fetuses were examined and no ultrasound detectable malformation was found. The volume for each FB was measured twice by the observers who used the Virtual Organ Computed-aided Analysis (VOCAL^TM) technique. Distinct sets of 12 and 6 planes were obtained after sequential rotations of 15° and 30°, respectively. The internal contour of fetal bladder was determined manually and carefully as to exclude adjacent structures from volume calculation. Wilcoxon signed-rank test was used for the comparison of paired samples in the cases of replication within and between observers. Spearman’s rank correlation was used to study the relationship among angles. Bland and Altman’s graphical approach was used to investigate the agreement between observers. Results Both techniques were shown to be highly reliable. No significant difference was found between the measurements of FB volume with the VOCAL^TM technique by varying either the steps of rotation or the observers. Conclusion Excellent correlations were found for both observers in the use of rotation angles of 15° and 30°. Since a significantly faster evaluation was obtained by using a 30° rotation step it must be preferred to assess the FB volume. Our results show that the VOCAL^TM technique, with a plane rotation of 30°, can be used in a simple way to estimate fetal urine production.     

Four-dimensional sonographic assessment of fetal movement in the late first trimester

Objective

To evaluate, using four-dimensional (4D) sonography, the frequency of fetal movements during the late first trimester of normal singleton pregnancies.

Methods

Singleton pregnancies were studied—using transvaginal 4D sonography—for 10 minutes at 10-11 and 12-13 weeks of gestation. The frequencies of 5 fetal movements (isolated arm, isolated leg, short trunk, long trunk, and jumping movements) were evaluated.

Results

In the 17 pregnancies studied, the most frequent fetal movements were isolated arm movement at 10-11 weeks and jumping movement at 12-13 weeks. There was a significant difference in the frequency of jumping movement between 10-11 and 12-13 weeks (P < 0.05).

Conclusion

The difference in frequency of 5 fetal movements at 10-11 and 12-13 weeks of gestation may be caused by early neuromuscular development and differentiation of the neuromuscular system.     

Placental volume relative to fetal weight estimated by sonography in diabetic pregnancies

Objective: Our purpose was to analyze the fetal weight and placental volume (PV) ratio in diabetic pregnancies during mid-pregnancy.

Method: One hundred and forty nine diabetic pregnancies [75 gestational diabetes mellitus (GDM) and 74 diabetes mellitus type I (T1DM) with good glycemic control] and 232 healthy patients were analyzed by three-dimensional sonographic volumetry of the placenta, while fetal weight was estimated by two-dimensional technique.

Results: The gestational age-specific estimated fetal weight (EFW) [EFWGDM: 1840.8?±?932.82?g; EFWT1DM: 1475.6?±?914.7?g (mean?±?standard deviation) and placental ratio (PR)] was significantly higher (p?<?0.05) in pregnancies complicated by GDM and T1DM (PRGDM: 5.5?±?1.67?g/cm³, PRT1DM: 4.56?±?3.2?g/cm³) compared to control group (Q) (EFWQ: 532?±?186.49?g; PRQ: 2.2?±?0.8?g/cm³), whereas PV was significantly higher (p?<?0.05) only in GDM (PVGDM: 334.3?±?111.5?cm³) compared to control data (PVQ: 232?±?78.9?cm³). In contrast to GDM, T1DM with good glycemic control did not predispose to any changes in placental sonographic volumetric differences compared to control values.

Conclusions: Fetal weight related to the PV is already elevated in second trimester in pregnancies complicated by gestational diabetes mellitus and type I diabetes mellitus compared to normal pregnancies.     

Comparison of the two-dimensional and multiplanar methods and establishment of a new constant for the measurement of fetal lung volume

Objectives. To compare the two-dimensional (2D) and multiplanar methods in the measurement of lung volume in normal fetuses, to obtain a new constant to be incorporated into the 2D equation, and to apply the new equation in fetuses with pulmonary hypoplasia (PH) confirmed postnatally.

Methods. A cross-sectional study was performed on 51 pregnant women at between 20 and 35 weeks of gestation. The ellipsoid formula (x × y × z × 0.52) was used to calculate lung volume by the 2D method. A sequence of multiple planes with 2.0-mm intervals was used with the multiplanar method. In order to compare the techniques, the intra-class correlation coefficient (ICC) and the Student's t-test (p) were used. First-order linear regressions were used to establish a new constant, with three-dimensional (3D) lung volume as dependent variable and gestational age and 2D volume as independent variables. In order to validate it, the new equation was applied to 11 fetuses with confirmed lethal PH.

Results. The mean volumes obtained by the 2D method were overestimated when compared to the multiplanar method (right lung: 23.87 vs. 18.26 mL, respectively, p < 0.001 and left lung: 16.18 vs. 14.33 mL, respectively, p = 0.008). Using a first-order polynomial regression, new constants were obtained for the right lung (0.152) and for the left lung (0.167). When compared to the traditional formula, the new equation presented higher sensitivity (18.1%) in predicting lethal PH.

Conclusion. The recalculated 2D equation can be a promising alternative to 3D ultrasonography in the prediction of PH.     

Three-dimensional versus two-dimensional ultrasound for fetal nasal bone evaluation in the second trimester

Objectives: To compare two-dimensional with three-dimensional ultrasound evaluation of the fetal nasal bone in the second trimester.

Methods: A prospective, non-interventional study was conducted, in 55 singleton fetuses, between 18 and 24 weeks’ gestation. Fetal nasal bone length was measured in the midsagittal plane by two-dimensional imaging and in the midsagittal and coronal plane with three-dimensional ultrasound. All three measurements were compared with one another using one-way repeated samples-measures ANOVA and paired samples t-test.

Results: The average fetal nasal bone length (mean?±?SD) as determined by the three methods was 7.01?±?0.94?mm for the two-dimensional midsagittal, 6.96?±?1.34?mm for the three-dimensional midsagittal, and 6.98?±?1.32?mm for the three-dimensional coronal plane; comparisons between one another were not statistically significant. Unilateral hypoplasia and bifid shape of the fetal nasal bone were detected in 8.2% and 20.4% of cases, respectively, by three-dimensional ultrasound, whereas all cases evaded detection with two-dimensional ultrasound (p?<?0.001 and p?=?0.001, respectively).

Conclusions: Fetal nasal bone length measured with two-dimensional ultrasound does not differ significantly from three-dimensional measurements. However, three-dimensional ultrasound is superior in detecting unilateral nasal bone hypoplasia or absence and in assessing fetal nasal bone shape. Hence, fetal nasal bone examination in the second trimester should include three-dimensional ultrasound evaluation.     

Smoking and its effect on maternal plasma volume during and after normal pregnancy

Smoking during pregnancy decreases birthweight significantly. The mechanisms causing this decrease have not yet been clarified. Plasma volume (expansion) is positively related to birthweight. There are indications that plasma volume expansion in pregnancy is lower among smokers. A group of healthy women (n = 70) producing healthy mature babies after an uncomplicated pregnancy was studied. No difference in plasma volume was observed between non-smokers and smokers during and after pregnancy. It is unlikely that the growth-depressing effect of smoking during pregnancy is mediated by an influence on plasma volume expansion.     

Prediction of lethal pulmonary hypoplasia by means fetal lung volume in skeletal dysplasias: a three-dimensional ultrasound assessment

Objective: The aim of this study was to assess the capacity of three-dimensional ultrasound (3DUS) for predicting lethality in fetuses with skeletal dysplasia.

Methods: Twenty-four fetuses between 20 and 32 weeks of gestation were assessed. Bilateral lung volume scans were performed three times in each fetus during one ultrasound session. The virtual organ computer-aided analysis method was used to obtain a sequence of six sections of each lung around a fixed axis, and a rotation angle of 30° was adopted. Fetal lung volume measurements were analyzed according to the reference range. After birth, lung hypoplasia was diagnosed considering clinical and radiological criteria.

Results: Of all cases of skeletal dysplasia, 18 (75%) were lethal. Among the lethal cases, after postnatal diagnosis, four were osteogenesis imperfecta type II, three were thanatophoric dysplasia and two were campomelic dysplasia. The remaining nine cases remained without a definitive diagnosis. The accuracy of 3DUS in predicting lethality in fetuses with skeletal dysplasia was high, with a sensitivity of 83.3%, specificity of 100%, positive predictive value of 100% and negative predictive value of 66.7%. The kappa index of 0.174 showed a good agreement between the possibility of lethality when the 3DUS volume measurement was altered and real lethality after birth (p?<?0.001).

Conclusion: This study suggests that the 3DUS lung volume measurement is a good predictor of lethal pulmonary hypoplasia in fetuses with skeletal dysplasia, with high accuracy.     

Three-dimensional reconstruction of fetal abnormalities using ultrasonography and magnetic resonance imaging

Objective: We aimed to compare three-dimensional (3D) fetal malformation images obtained using ultrasonography (US) and magnetic resonance imaging (MRI) on the same day during the third trimester of pregnancy.

Methods: Total 33 fetuses were selected from cases evaluated for malformations. Morphological abnormalities were first scanned using 3DUS. MRI was used to confirm the previous preliminary 3DUS findings, and diagnoses were confirmed postnatally. 3DUS scans were performed transabdominally using an Rab (4–8?L) probe, Voluson 730 Pro/Expert and E8 (General Electric, Healthcare, Zipf, Austria). MRI was performed using a 1.5-T scanner (Magneton Avanto, Siemens, Erlangen, Germany) with a body coil. The 3D reconstruction of the structure of interest was manually performed from a True FISP sequence using an interactive pen tablet (Syngo multimodality 2009B, Siemens, Erlangen, Germany).

Results: Despite recent advancements in 3DUS, the quality of 3D images obtained from MRI was superior during the third trimester. 3DUS had certain limitations, such as being influenced by the fetal position, the volume of amniotic fluid, and maternal obesity. Fetal movements during image acquisition were one of the main challenges for MRI.

Conclusion: The quality of the 3D images obtained using MRI was superior to that of images obtained using US during the third trimester of pregnancy.     

Reference range of fetal cisterna magna volume by three-dimensional ultrasonography using the VOCAL method

Abstract

Objective: To determine reference values for the fetal cisterna magna volume by three-dimensional ultrasonography (3DUS) using the virtual organ computer-aided analysis (VOCAL) method.

Methods: A cross-sectional study was conducted with 224 healthy pregnant women between 17 and 29 completed weeks. Measurement of the fetal cisterna magna volume was performed in the standard axial plane of the transverse diameter of the cerebellum through the VOCAL method with a 30° angle. For the determination of reference values, polynomial regressions with adjustments by the coefficient of determination (R²) were held. The reliability and agreement were made by the intra-class correlation coefficient (ICC) and limits of agreement of the Bland-Altman graph.

Results: The average of the fetal cisterna magna volume ranged from 0.73?±?0.25 to 3.79?±?1.10?cm³ between 17 and 29 weeks, respectively. Correlation was observed between the fetal cisterna magna volume and the gestational age (GA), best represented by a quadratic equation: ?1.918+0.0284?×?GA + 0.0065?×?GA² (R^2?=?0.67). It was observed good reliability and intra-observer agreement, with ICC?=?0.92 and 95% limits of agreement (?49.7; 48.4). There was low inter-observer reliability and agreement, with ICC?=?0.58 and 95% limits of agreement (?114.0; 80.2).

Conclusion: Reference values for the fetal cisterna magna volume by 3DUS using the VOCAL method were determined and showed good agreement and intra-observer reliability.     

Three-dimensional ultrasound in the imaging of multifetal pregnancy

The great advances in imaging techniques, such as high-resolution probes and three-dimensional ultrasound, have enabled us to image multifetal pregnancies from the time β-human chorionic gonadotropin is positive. The importance of three-dimensional sonographic evaluation of multifetal pregnancy before 12 weeks of gestation, using multiplanar sections and surface rendering, should be emphasized. In this review, we also discuss the importance of three-dimensional ultrasound imaging in second- and third-trimester multifetal pregnancy, and in the assessment of fetal weight and amniotic fluid volume. Finally, we outline the importance of novel techniques: three-dimensional power Doppler and four-dimensional ultrasound in the field of multifetal pregnancy and in performance of interventional procedures. Because three-dimensional ultrasound is still a novel sonographic modality, many of its potential utilities await studies to prove efficacy and cost-effectiveness.     

Normal standards of fetal behavior assessed by four-dimensional sonography

Objective.?In this prospective randomized study, fetal behavior was investigated in order to determine the standard parameters of fetal movements and facial expressions in all three trimesters of normal pregnancy.

Methods.?Sixty-three pregnant women with singleton pregnancies in all trimesters were included in the investigation. Four-dimensional (4D) ultrasound was performed for each patient over a 30-minute period. Variables of maternal and fetal characteristics including gestational age, eight fetal movement patterns in the first trimester, and sixteen parameters of fetal movement and fetal facial expression patterns in the second and third trimesters were recorded for the construction of fetal neurological charts.

Results.?In the first trimester, a tendency towards an increased frequency of fetal movement patterns with increasing gestational age was noticed. Only the startle movement pattern seemed to occur stagnantly during the first trimester (p > 0.05). At the beginning of the second trimester, the frequency of fetal movement patterns tended to increase. During the second and third trimester, multiple regression and polynomial regression revealed statistically significant changes in tongue expulsion (p < 0.05), smiling (p < 0.05), grimacing (p < 0.05), swallowing (p < 0.05), eye blinking (p < 0.01), head movements, and all hand to body contact movements (p < 0.01), except for head anteflexion (p > 0.05). There were no statistically significant changes during the second and third trimesters in mouthing, yawning, and sucking (p > 0.05). At the middle of the third trimester, the fetuses displayed decreasing or stagnant incidence of fetal facial expressions except for eye blinking, which showed increased frequency with increasing gestational age. A statistically significant correlation was found between all head movements and hand to body contact patterns during the second and third trimesters except for head anteflexion (r = ?0.231; p > 0.05).

Conclusions.?The full range of quantitative fetal facial expressions and fetal movement patterns can be assessed successfully by 4D sonography. It is important to be able to assess normal fetal behavior throughout gestation to identify abnormal behavior before birth.     

Three-dimensional sonographic features of fetal central nervous system anomaly

OBJECTIVE: To visualize an intracranial structure of the fetal central nervous system (CNS) anomaly using transabdominal three-dimensional (3D) sonography. METHODS: A total of 12 cases with fetal CNS anomalies (one unilateral ventriculomegaly; three hydrocephalus; three anencephaly; three holoprosencephaly; one Dandy-Walker cyst; and one enlarged cisterna magna) from 17 to 37 weeks of gestation were studied with transabdominal 3D sonography (3.5 MHz). RESULTS: In unilateral ventriculomegaly, insight view of dilated lateral ventricle, especially dilated atrium was depicted. In hydrocephalus, severely dilated bilateral ventricles and thin brain mantle were very clearly shown. In anencephalus, an absence of the brain and defect of the vault of the skull was clearly noted. In holoprosencephaly, absent interhemispheric fissure, common ventricle, and the extent of thalamic fusion were evident. In Dandy-Walker cyst, cerebellar hemisphere was clearly depicted due to the agenesis of cerebellar vermis. In enlarged cisterna magna, posterior intracranial view of the fetus showed a large space of cisterna magna. Although the diagnosis of each CNS anomaly was made using conventional two-dimensional sonography, 3D sonography proved most helpful delineating the exact nature and anatomic level of the anomaly. CONCLUSIONS: These results suggest that 3D sonography provides a novel means of visualizing fetal CNS anomalies in utero. However, it should be noted that our 3D sonography cannot depict intracranial brain structures in normal fetuses or some CNS anomaly such as intracranial tumor.     

Erroneous statement regarding 2D ultrasound fetal urinary bladder volume measurement

The aim of the current paper is to inform the readers of an erroneous statement on the standard deviation (SD) when estimating the volume of fetal urinary bladder by 2D ultrasound. In the Archives of Gynecology and Obstetrics 2007; 276 (4), page 345-349, the authors Peixoto-Filho F.M. et al. refer to some studies presented by our group versus other studies regarding volume estimation of the fetal urinary bladder, in particular the ellipsoid method pioneered by Stuart Campbell in 1973 and the sum-of-cylinders method from our group. In our studies the volume estimation method was improved in three steps using methodological modifications. The SD was reduced from 17.3-10.9% to 12.9-5.5%, and 8.8-3.5% (bladder volumes 5-40 mL) The reductions were accompanied by P-values of 0.0270 (1 vs. 2) and 0.0543 (2 vs. 3), respectively. When comparing method 3 vs. 1 the P value was 0.0032. The SD reduction using method 3 vs. 2 did not reach statistical significance, however. Using this lack of significance on the 5% significance level, to prove that there were no improvements at all with our methodological modifications of the 2D ultrasound, as done by the authors, is misleading.     

Fetal thymus: visualization rate and volume by integrating 2D- and 3D-ultrasound during 2nd trimester echocardiography

Objective: To assess the visualization rate and transverse diameter of fetal thymus by two-dimensional ultrasound (2DUS) as well as the fetal thymus volume by three-dimensional ultrasound (3DUS) during the 2nd trimester echocardiography.

Methods: A prospective cross-sectional study involving 100 normal fetuses between 18w0d and 23w6d was performed. The identification of fetal thymus and peri-thymic vessels was realized at level of three vessels and trachea (3VT). The transverse diameter was obtained placing a line cursor perpendicular to the line connecting the sternum and the spine. The fetal thymus volume was obtained by virtual organ computer-aided analysis (VOCAL) with 30° of rotation. We used the percentage of visualization rate of 2D structures and means and 95% confidence intervals (CI) for fetal thymus transverse diameter and volume.

Results: The visualization rate of fetal thymus by 2DUS was of 100% in all gestational ages using the 3VT view. Addition of color Doppler ultrasound facilitates identification of the thy-box and enhanced the calculation of both fetal thymus transverse diameter and volume. The mean fetal thymus transverse diameter by 2DUS ranged from 11?mm at 18 weeks to 19?mm at 23 weeks of gestation. The mean fetal thymus volume by 3DUS ranged from 1.25?cm³ at 18 weeks to 2.61?cm³ at 23 weeks of gestation.

Conclusion: We demonstrated a high visualization rate of fetal thymus and peri-thymic vessels by 2DUS during the 2nd trimester echocardiography. The measurements of transverse diameter by 2DUS and the volume by 3DUS also showed a high success rate.     

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.     

Three-dimensional sonographic visualization of fetal skeleton in the second trimester of pregnancy

PURPOSE: To demonstrate the potential of using three-dimensional (3D) sonography to reveal anomalies of fetal skeleton. MATERIALS AND METHODS: Forty-two normal fetuses and 3 anencephalic fetuses from 14 to 27 weeks' gestation were studied with a specially developed abdominal 3D transducer (3.5 MHz). This imaging system provided conventional two-dimensional (2D) sonographic images and also generated within seconds high-quality 3D images in the surface and transparent mode with no need for an external workstation. RESULTS: Using this imaging system, we obtained 2D and 3D images of fetal skeleton (skull, scapula, spine, rib, humerus, ulna/radius, pelvis, femur, and tibia/fibula) at two gestational ages. The percentages of fetal skeletal visualization at less than 20 weeks of gestation using 3D sonography were 78-100%, whereas those with 2D sonography were all 100%. The percentages of skeletal structures revealed after 20 weeks' gestation using 3D sonography were 82-100%, whereas those with 2D sonography were all 100%. We found no significant differences in detection rates of the fetal skeleton between 2D and 3D sonography. However, 3D sonographic images generally provided a more comprehensive view of the fetal skeleton than did conventional 2D sonography. In 2 cases with anencephaly, 3D sonography clearly revealed the defect of cranium. CONCLUSION: The new 3D sonographic technology can generate within seconds high-quality 3D images of the fetal skeleton. The 3D technology seems to perform at least as well as conventional 2D sonography. Our results suggest that 3D sonography has the potential to supplement 2D sonography and might be useful in identifying malformations of the fetal skeleton and chromosomal abnormalities in utero.