OBJECTIVE: To evaluate the interobserver reproducibility of vascular indices obtained with three-dimensional power Doppler (3D power Doppler) ultrasonography at the first trimester of gestation. MATERIALS AND METHODS: The present reproducibility study involved 32 healthy pregnant women with 7 to 10 weeks and 6 days of gestation. The VOCAL (Virtual Organ Computer-aided AnaLysis) method was utilized to calculate embryos volume, with a 12° rotational angle. Subsequently, the software automatically displayed three 3D power Doppler vascular indices: vascularization index (VI), flow index (FI) and vascularization and flow index (VFI). In order to calculate the interobserver variability, an investigator performed a second blind measurement of the 32 embryos, and another investigator performed a third blind measurement of the same volumes. The interclass correlation coefficient (ICC) and Bland-Altman plots were utilized for statistical analysis. RESULTS: A good interobserver reproducibility was observed in relation to the three vascular indices. The VI presented ICC = 0.9 and mean difference between measurements = -1.1. For the FI, the ICC was 0.9 and mean difference = -0.5. The VFI presented ICC = 0.9 and mean difference = -1.1. CONCLUSION: The vascular indices, particularly the FI, obtained with 3D power Doppler ultrasonography at the first trimester of gestation demonstrated a high reproducibility.

Keywords: First trimester of gestation, Color Doppler ultrasonography, Reproducibility of results, Three-dimensional imaging

OBJECTIVE: To evaluate fetal nuchal translucency, ductus venosus, nasal bone and maternal age > 35 years by means of aneuploidy screening between the 12th and 14th gestational weeks in a high-risk population. MATERIALS AND METHODS: Prospective, observational study involving 92 pregnant women at 12-14 gestational weeks, who were submitted to chorionic villus sampling because of high risk for trisomy 21 based on the measurement of nuchal translucency thickness (17.4%) or on maternal age > 35 years (78.3%). Before the chorionic villus sampling, fetal nuchal translucency thickness was measured, ductus venosus flow was evaluated and the nasal bone was identified. Sensitivity, specificity, positive predictive value and negative predictive value were calculated for tests in parallel and in sequence. RESULTS: Chromosomal abnormalities were found in 12 fetuses (13.5%); 7 (58.3%) were positive for trisomy 21. The nasal bone was present in all cases with chromosomal abnormalities. Isolated nuchal translucency, ductus venosus or maternal age showed low sensitivity (41.67-58.33%) and low positive predictive value (10-45.45%). Combined nuchal translucency + ductus venosus + maternal age showed the best results (100% sensitivity; 6.49% specificity; 14.29% positive predictive value; 100% negative predictive value). CONCLUSION: In pregnant women with >35 years of age, combined nuchal translucency + ductus venosus have showed the highest sensitivity as an indication for invasive procedure.

Keywords: Nuchal translucency measurement, Ductus venosus, Nasal bone, Maternal age, Trisomy

OBJECTIVE: To establish reference values for fetal nasal bone length measurements between 11 and 15 gestational weeks in a Brazilian population. MATERIALS AND METHODS: A cross-sectional study was developed with 171 normal pregnant women between their 11th and 15th gestational weeks. The fetal nasal bone was measured by means of transabdominal ultrasound in all of the cases. The 5th and 95th percentiles for the nasal bone length were calculated by the formula: mean ± 1.645 standard deviation. The Spearman correlation coefficient with 95% confidence interval was utilized to correlate the nasal bone length with fetal anthropometric parameters. RESULTS: The nasal bone could be measured in all of the cases with the mean length ranging between 1.69 mm and 2.94 mm. Nasal bone length demonstrated to be strongly correlated with all of the fetal anthropometric parameters (p < 0.001) and with the gestational age (R² = 0.59). CONCLUSION: Despite the preliminary character of the present study, a reference range of fetal nasal bone length was established.

Keywords: Fetal biometry, Nasal bone, Normality range, Ultrasound

OBJECTIVE: To determine reference values for placental volume at 7 to 10 + 6 weeks of gestation by means of three-dimensional ultrasonography with the XI VOCAL (eXtended Imaging Virtual Organ Computer-aided Analysis) method. MATERIALS AND METHODS: A cross-sectional study was developed with 70 pregnant women at 7 to 10 + 6 weeks of gestation. The XI VOCAL method with ten sequential adjacent planes was utilized in the volume calculations. Means, medians, standard deviation, minimum and maximum values for placental volume were calculated. A scatter plot adjusted by the determination coefficient (R²) was constructed to correlate placental volume and gestational age. RESULTS: Mean placental volume ranged from 4.6 cm³ (2.6-8.6 cm³) to 28.9 cm³ (11.4-66.9 cm³). The placental volume (PV) has shown to be highly correlated with the gestational age (GA) and the best fit equation was [PV = exp(0.582 × GA + 0.063); R² = 0.82]. CONCLUSION: Reference values for placental volume in the first gestational trimester were determined with the XI VOCAL method.

Keywords: Early placental phase, First trimester of pregnancy, Gestational age, Organ volume, Three-dimensional imaging

Cardiac tumors constitute a rare condition, affecting 0.17-28/10,000 of the general population. Rhabdomyomas represent the most frequently found type of tumor in the prenatal period. The present report describes the case of a 31-week fetus presenting with a large intracardiac tumor with severe clinical repercussions.

Keywords: Prenatal diagnosis, Ultrasonography, Fetal masses, Fetal tumors

OBJECTIVE: To evaluate the correlation between the yolk sac volume measured by three-dimensional ultrasonography with gestational age at 7-10 weeks. MATERIALS AND METHODS: A cross-sectional study involving 72 healthy pregnant women at 7th-10th gestational weeks. The multiplanar method with 1.0 mm intervals was utilized. Regression models were constructed to analyze the correlation between yolk sac volume and gestational age, adjusted by the determination coefficient (R²). Mean, median, standard deviation, maximum and minimum values for yolk sac volume were calculated for each gestational age. RESULTS: A poor correlation was observed between yolk sac volume (YSV) and gestational age (GA). The quadratic regression was the model that best expressed this correlation: YSV = 0.9757 - 0.2499 × GA + 0.0172 × GA² (R² = 0.234). Mean yolk sac volume ranged from 0.07 cm³ (0.02-0.11) to 0.20 cm³ (0.02-0.74) between the 7th and 10th weeks (mean, 0.11 cm³, ± 0.10 cm³). CONCLUSION: There was a poor correlation between yolk sac volume and gestational age.

Keywords: Yolk sac, First trimester of pregnancy, Gestational age, Prenatal ultrasonography, Three-dimensional imaging

OBJECTIVE: To determine a reference curve for the peak systolic velocity of fetal middle cerebral artery. MATERIALS AND METHODS: The authors developed a cross-sectional study with 143 healthy pregnant women between the 23rd and 35th gestational weeks. A bidimensional axial scan of the fetal skull was performed, including the thalami and pellucid septum. Subsequently, the middle cerebral artery was visualized with the color Doppler mode. The pulsed-wave Doppler transducer was positioned over the origin of this vessel, at < 20° insonation angle. The correlation between the peak systolic velocity of the middle cerebral artery and gestational age was evaluated by means of the Pearson's correlation coefficient (r). Regression models were utilized in the construction of a table with multiples of the medians of the middle cerebral artery peak systolic velocity for each gestational age. Additionally, reference values for this variable were determined. RESULTS: A strong correlation was observed between the middle cerebral artery peak systolic velocity and gestational age (r = 0.70; p < 0.001). Values of middle cerebral artery peak systolic velocity were calculated for the following multiples of the medians: 1.0, 1.29, 1.5, 1.55. The 2.5th and 97.5th percentiles were determined for the middle cerebral artery peak systolic velocity ranging between 24.33 cm²/s and 78.36 cm²/s. CONCLUSION: A nomogram for the fetal middle cerebral artery peak systolic velocity during the second half of pregnancy was generated.

Keywords: Middle cerebral artery, Doppler, Ultrasonography, Nomogram, Fetus

For the last years three-dimensional ultrasonography has become an imaging diagnosis method of great importance in obstetrics. One of its advantages would be the higher sensitivity compared with two-dimensional ultrasound in the diagnosis of some fetal malformations. The potential applications of this new method would be an improved accuracy in the measurement of fetal organs, the possibility of reviewing volumes in the absence of the patient, and using different planes to assess specific anatomical structures, as well as the capacity to transfer data files to remote reference centers. Ultrasonographic evaluation of fetal cerebellum is particularly important, since developmental alterations are correlated with the fetal growth alterations and congenital anomalies. The objective of this updating is to demonstrate the VOCAL™ and 3D XI™ methods in the evaluation of the fetal cerebellum, their potential benefits, and the latest information in the literature about this subject.

Keywords: Fetus, Cerebellum, Volume of organs, Prenatal diagnosis, Three-dimensional ultrasound

The fetal limb volume reflects the nutritional status and intra-uterine growth of the fetus. The arrival of the three-dimensional ultrasound has allowed a more accurate volumetric evaluation of irregularly shaped structures such as fetal organs. The three-dimensional multiplanar mode is the most efficient technique to evaluate fetal limb volume as a parameter for a more accurate birth weight prediction. Currently, this method is useful for monitoring the development of soft tissue and for early detection of fetal growth deviations. In our country, where fetal growth restriction is frequent, with poor access to a skilled neonatal assistance, the dissemination of this technique could definitely contribute to reduce the rates of perinatal morbidity and mortality.

Keywords: Three-dimensional ultrasound, Fetal limbs, Volume

OBJECTIVE: To evaluate and compare existing ultrasound findings in women with Rh-alloimmunized pregnancies with diagnosis of fetal anemia by spectrophotometric analysis of amniotic fluid or Doppler ultrasound of the fetal middle cerebral artery. MATERIALS AND METHODS: This was an observational descriptive study involving 99 patients evaluated between January 1995 and January 2004. Patients were divided into two groups: 74 Rh-isoimmunized women submitted to spectrophotometry of the amniotic fluid (group S) and 25 Rh-isoimmunized women submitted to Doppler ultrasound of fetal middle cerebral artery (group D) to evaluate fetal anemia. Ultrasound findings in the two groups were compared. RESULTS: Placental anomalies, mainly placentomegaly and textural irregularities were more frequently seen in pregnant women followed up with spectrophotometry of the amniotic fluid compared to those followed up with Doppler ultrasound (64% X 32%, p = 6,294). CONCLUSION: The frequency of abnormal ultrasound findings was 2-fold higher in pregnancies evaluated with spectrophotometry of the amniotic fluid compared to those followed up with Doppler ultrasound.

Keywords: Red blood cell isoimmunization, Fetal anemia, Middle cerebral artery, Doppler ultrasonography, Isoantibodies, Fetal erythroblastosis

Although congenital heart defect is the most frequent anomaly in newborns, its antenatal detection rate through conventional ultrasound remains low. 3D and 4D ultrasound technology was developed early in the nineties, bringing great benefits in obstetrics, especially in cases of dubious diagnosis at 2D ultrasound. The spatio-temporal image correlation (STIC) is a significant development in the field of 4D ultrasound. A software coupled with a Voluson 730 Expert equipment allows a volumetric acquisition of the fetal heart and its vascular connections. Volumetric analyses are performed in multiplanar and surface rendering modes or, alternatively in association with color Doppler. Major advantages are fast images acquisition and the possibility of a later analysis by fetal echocardiography specialists. Differently from 2D ultrasound, this technique may be applied for evaluating any congenital cardiopathy because of the increased number of frames acquired from a specific anatomical region. Main disadvantage is related to the necessity of fetal immobility. The higher diffusion of this method may improve prenatal detection of heart malformations since volumes data captured by a sonographer may be sent through the Internet for analysis by fetal echocardiography specialists.

Keywords: Congenital heart defect, Prenatal diagnosis, STIC

OBJECTIVE: To assess the reproducibility of fetal thigh and upper arm volumes measurement by threedimensional ultrasonography utilizing the eXtended Imaging Virtual Organ Computer-aided AnaLysis (XI VOCAL) method. MATERIALS AND METHODS: This reproducibility study enrolled 43 pregnant women with healthy singleton pregnancies between 20 and 37 gestational weeks. The XI VOCAL 10 planes was the method utilized for volumetric measurement of the fetal limbs. The calculation of the interobserver reproducibility was based on blind volumetric measurements of fetal thighs and upper-arms performed by two observers in 43 fetuses. Intraclass correlation coefficient (ICC), Bland-Altman plots and paired Student's t-test (p) were utilized in the statistical analysis. RESULTS: A high interobserver reproducibility was observed. For the upper arm volume ICC was 0.996 (confidence interval [CI] 95%: 0.992; 0.998) and mean difference = 0.13 ± 1.29% (95% limits of agreement: -2.54; +2.54%). For the thigh volume, ICC was 0.997 (CI 95%: 0.995; 0.999) and mean difference = 0.24 ± 7.60% (95% limits of agreement: -7.6; +7.6%). CONCLUSION: Fetal thigh and upper arm volumes measured by three-dimensional ultrasonography with the XI VOCAL method presented a high interobserver reproducibility.

Keywords: Reproducibility; Fetal limbs volume; Three-dimensional ultrasonography; XI VOCAL.

Objective: To evaluate the intra- and interobserver reproducibility of three-dimensional power Doppler sonography (3D power Doppler) in the assessment of fetal brain blood flow in the middle cerebral artery territory. Materials and methods: A cross-sectional study was developed with 20 healthy pregnant women between 26 and 34 gestational weeks. The middle cerebral artery territory closest to the transducer was scanned and the blood flow volume was calculated with the method Virtual Organ Computer-aided AnaLysis. The following 3D power Doppler indices were later obtained: vascularization index (VI), flow index (FI) and vascularization-flow index (VFI). The intraclass correlation coefficient (ICC) and Bland-Altman plots were utilized for calculating the intra- and interobserver variability. Results: A good intra- and interobserver agreement was observed, with ICC > 0.90 for all the 3D power Doppler indices: VI [ICC = 0.992 (CI 95%: 0.981–0.997)], FI [ICC = 0.999 (CI 95%: 0.998–0.999)], VFI [ICC = 0.995 (CI 95%: 0.987–0.998)]. Interobserver reproducibility: VI [ICC = 0.988 (CI 95%: 0.970–0.995)], FI [ICC = 0.999 (CI 95%: 0.997– 1.000)], VFI [ICC = 0.994 (CI 95%: 0.994–0.998)]. Conclusion: 3D power Doppler has shown to be a practical and easy method in the assessment of fetal brain blood flow, with good intra- and interobserver reproducibility. The FI presented the best intra- and interobserver agreement.

Keywords: Reproducibility of results; Prenatal ultrasonography; Fetal brain flow; Power Doppler; Threedimensional sonography.

Objective: To evaluate the possible repercussions of the previous cesarean scar at uterine arteries Doppler velocimetry between the 26th and 32nd gestational weeks. Materials and Methods: Prospective cross-sectional study including 45 women between 11 and 14 weeks of gestation, divided into three groups: 17 pregnant women with uterine scar resulting from a previous elective cesarean section (group A); 14 with uterine scar resulting from a previous cesarean section performed during labor (group B); and 14 pregnant women with a single previous vaginal delivery (group C). Uterine arteries Doppler velocimetry was performed with transabdominal approach. Means, medians and standard deviation (SD) were calculated for each group in the study. The groups comparison regarding pulsatility index was performed with the non-parametric Kruskal-Wallis test. Results: In group A, the pulsatility index ranged from 0.60 to 1.60 (mean: 0.90; SD: 0.29), in group B, from 0.53 to 1.43 (mean: 0.87; SD: 0.24), and in group C, from 0.65 to 1.65 (mean: 1.01; SD: 0.37); with p = 0.6329. Conclusion: No repercussion of previous cesarean scar was observed at uterine arteries Doppler velocimetry performed in the period between the 26th and 32nd gestational weeks.

Keywords: Pregnancy; Uterine scar; Previous cesarean section; Uterine arteries Doppler velocimetry.

A congenital ranula is a rare cystic malformation seen in the oral cavity. This pseudocyst is normally located in the sublingual space between the mylohyoid muscle and the lingual mucosa. A 24-year-old woman, gravida 3, para 2, at 29 weeks' gestation was referred to our institution because of polihydramnios and large oral mass.

Keywords: Prenatal diagnosis; Ultrasound; Oral tumor; Ranula.

Beckwith-Wiedemann syndrome is a genetic syndrome characterized by macroglossia, omphalocele, fetal gigantism and neonatal hypoglycemia. The authors report a case of Beckwith-Wiedemann syndrome diagnosed in a 32-year-old primigravida in whom two-dimensional ultrasonography revealed the presence of abdominal wall cyst, macroglossia and polycystic kidneys. Three-dimensional ultrasonography in rendering mode was of great importance to confirm the previous two-dimensional ultrasonography findings.

Keywords: Prenatal diagnosis; Beckwith-Wiedemann syndrome; Two-dimensional ultrasonography; Three-dimensional ultrasonography.

OBJECTIVE: To establish reference intervals for the fetal cisterna magna volume by means of two-dimensional (2D) method using the multiplanar mode of three-dimensional ultrasonography. MATERIALS AND METHODS: Cross-sectional study with 224 healthy pregnant women between the 17th and 29th gestational weeks. The volume was automatically obtained by multiplying the three major axes in axial and sagittal planes by the constant 0.52. Polynomial regression was utilized to establish the correlation between fetal cisterna magna volume and gestational age, with adjustments by coefficient of determination (R²). Reliability and agreement were obtained by intraclass correlation coefficient (ICC) and limits of agreement, respectively. RESULTS: Mean fetal cisterna volume with the 2D method ranged from 0.71 ± 0.19 cm³ to 4.18 ± 0.75 cm³ at the 17th and 29th weeks, respectively. The authors observed a good correlation between fetal cisterna magna volume and gestational age (R² = 0.67), excellent intraobserver reliability and agreement with ICC = 0.89 and limits of agreement 95% (–52.0; 51.8), respectively, and low interobserver reliability and agreement with ICC = 0.64 and limits of agreement 95% (–110.1; 84.6), respectively. CONCLUSION: Reference intervals for fetal cisterna magna volume by means of 2D method using the multiplanar mode of three-dimensional ultrasonography were established and presented excellent intraobserver reliability and agreement.

Keywords: Fetus; Cisterna magna; Reference intervals; Two-dimensional ultrasonography; Three-dimensional ultrasonography.

Fetal development is studied since the advent of two-dimensional ultrasonography. However, a detailed assessment of structures and surfaces improved with three-dimensional ultrasonography. Currently, it is possible to identify embryonic components and fetal parts with greater detail, at all pregnancy trimesters, using the HD live software, where the images gain realistic features by means of appropriate control of lighting and shadowing effects. In the present study, the authors utilized this resource to follow-up, by means of images, the development of a normal pregnancy along all trimesters.

Keywords: Embryo; Fetus; Normal development; Three-dimensional ultrasonography; HD live.

Central nervous system malformations constitute the second most common group of anomalies in fetuses. Such malformations have assumed clinical importance because of their association with high rates of perinatal morbidity and mortality. Therefore, it is extremely important to assess the fetal central nervous system during the prenatal period, in order to identify any changes in its development and thereby gain sufficient information to advise parents about pregnancy follow-up, options for fetal therapy, and the timing/type of delivery, as well as the postnatal treatment and prognosis. The objective of this review was to describe the ultrasonographic evaluation of the fetal central nervous system as per the guidelines of the International Society of Ultrasound in Obstetrics and Gynecology.

Keywords: Fetus; Central nervous system; Ultrasonography; Practice guidelines as topic.