Prediction of preeclampsia in the first trimester of pregnancy using maternal characteristics, mean arterial pressure, and uterine artery Doppler data in a Brazilian population.

OBJECTIVE: To evaluate the performance of the preeclampsia (PE) screening algorithm of the Fetal Medicine Foundation (FMF) during the first trimester in a Brazilian population using maternal characteristics, mean arterial pressure (MAP), and uterine artery Doppler data. METHODS: This is a prospective cohort study that evaluated 701 pregnant women during the first trimester ultrasound screening for chromosomal abnormalities (11-13+6 weeks). All patients provided information regarding clinical and obstetric history, MAP, and mean uterine artery pulsatility index (mean PI). Patients were assigned to four groups based on the presence of PE and gestational age at delivery: group 1 (control), patients without hypertensive disorders (n=571); group 2, PE and delivery before 34 weeks of gestation (n=7); group 3, PE and delivery before 37 weeks of gestation, including patients from group 2 and patients that presented PE with delivery between 34 and 37 weeks (n=17); and group 4, PE and delivery before 42 weeks of gestation, including patients from both groups 2 and 3 and patients that presented PE with delivery between 37 and 42 weeks of gestation (n=34). RESULTS: After the exclusion of 96 patients, we evaluated the data of 605 patients. By combining maternal characteristics, MAP, and the mean uterine artery PI for the detection of PE, we found a sensitivity of 71.4% in group 2, 50% in group 3, and 41.2% in group 4 (false positive rate=10%). CONCLUSION: Using maternal characteristics, MAP, and uterine artery Doppler data, we were able to identify a significant proportion of patients who developed preterm PE.

Validation of Fetal Medicine Foundation algorithm for prediction of pre-eclampsia in the first trimester in an unselected Brazilian population.

OBJECTIVE: The objective of this study is to evaluate the predictive performance of the Fetal Medicine Foundation (FMF) algorithm for prediction of preeclampsia (PE) between 11 and 14 weeks of gestation in an unselected Brazilian population. METHODS: We conducted a prospective cohort study with 617 singleton pregnancies of unselected risk. Biophysical markers (mean pulsatility index, mean arterial pressure) and biochemical markers (placental growth factor (PLGF) and PAPP-A) were inserted into the FMF software and converted into multiples of the median (MoM). The subjects were divided into five groups: early-onset PE, parturition <34 weeks' gestation; preterm PE, parturition <37 weeks; PE, parturition at any gestational age; gestational hypertension (GH); and control group. Areas under the receiver operating characteristics curve (AUC) were calculated for the outcomes. RESULTS: Among 617 patients, seven developed early-onset PE, 18 developed preterm PE (seven early PE plus 11 delivered between 34 and 36 + 6 weeks gestation), 34 developed PE (18 preterm PE plus 16 delivered after 37-week gestation), 12 pregnant women developed GH, and 517 women comprised the control group. The best predictive performance using the FMF algorithm occurred in the early-onset PE group, with AUC = 0.946 (95% CI 0.919-0.973) and the detection rate of 28.6% and 85.7% for 5% and 10% false-positive (FP), respectively. CONCLUSIONS: The FMF algorithm to predict PE was effective in a Brazilian population, mainly in the early-onset form of the disease at 10% FP.

Reproducibility of three-dimensional power Doppler placental vascular indices in pregnancies between 26 and 35 weeks.

PURPOSE: Assess intra and interobserver reproducibility of three-dimensional power Doppler (3DPD) placental vascular indices in normal pregnancies between 26 and 35 weeks. METHODS: Thirty 3D volumes were captured by one observer and stored for analysis. Vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated from the spherical placental tissue samples obtained through the automatic Virtual Organ Computer-aided AnaLysis (VOCAL). Two observers analyzed the stored volumes and calculated the indices and their findings were compared. Intraclass correlation coefficients (ICCs) were used to analyze intra and interobserver correlations. Data were analyzed using confidence intervals, reliability coefficients and Bland-Altman graphs with concordance limits. RESULTS: All three indices had good intra and interobserver reproducibility. Intraobserver ICCs for the three indices were > 0.90. The FI had the highest ICC (0.99), the highest interobserver ICC (0.98) and the best concordance on the Bland-Altman graphs. CONCLUSION: 3DPD placental vascular indices obtained using the automatic sphere mode had a good intra and interobserver reproducibility for pregnancies between 26 and 35 weeks. The FI obtained the highest reproducibility scores.

Reprodutibilidade interobservador dos índices vasculares do Doppler de amplitude tridimensional do embrião entre 7 e 10 semanas e 6 dias de gestação / Interobserver reproducibility of vascular indices obtained with three-dimensional power Doppler ultrasonography of embryos at 7 to 10 weeks and 6 days of gestation

OBJETIVO: Avaliar a reprodutibilidade interobservador dos índices de vascularização do Doppler de amplitude tridimensional (Doppler de amplitude 3D) no primeiro trimestre de gestação. MATERIAIS E MÉTODOS: Realizou-se estudo de reprodutibilidade com 32 gestantes normais entre 7 e 10 semanas e 6 dias. Para o cálculo do volume tridimensional dos embriões utilizou-se o método VOCAL (Virtual Organ Computer-aided AnaLysis) com ângulo de rotação de 12°. Em seguida obtiveram-se, automaticamente, os três índices vasculares do Doppler de amplitude 3D: índice de vascularização (VI), índice de fluxo (FI) e índice de vascularização e fluxo (VFI). Para o cálculo da variabilidade interobservador, um examinador realizou uma segunda medida dos 32 embriões e um segundo examinador realizou uma terceira medida dos mesmos volumes, ambos desconhecendo os resultados do outro. Utilizaram-se, para análise estatística, o coeficiente de correlação intraclasse (CCI) e gráficos de Bland-Altman. RESULTADOS: Observou-se boa reprodutibilidade interobservador dos três índices vasculares. O VI apresentou CCI = 0,9 e média da diferença = -1,1; o FI apresentou CCI = 0,9 e média da diferença = -0,5; e o VFI apresentou CCI = 0,9 e média da diferença = -1,1. CONCLUSÃO: Os índices vasculares do Doppler de amplitude 3D do embrião no primeiro trimestre de gestação foram altamente reprodutíveis, em especial o FI.

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.

Avaliação do volume da placenta no primeiro trimestre de gestação por meio da ultrassonografia tridimensional utilizando o método XI VOCAL / Estimation of placental volume by three-dimensional ultrasonography with the XI VOCAL method in the first gestational trimester

OBJETIVO: Determinar valores de referência para o volume da placenta entre 7 e 10 semanas e 6 dias de gestação por meio da ultrassonografia tridimensional utilizando o método XI VOCAL (eXtended Imaging Virtual Organ Computer-aided Analysis). MATERIAIS E MÉTODOS: Realizou-se estudo de corte transversal com 70 gestantes normais entre 7 e 10 semanas e 6 dias. Para o cálculo de volume, utilizou-se o método XI VOCAL com delimitação de dez planos adjacentes. Foram determinadas médias, medianas, desvios-padrão, valores máximo e mínimo para o volume da placenta. Para avaliar a correlação do volume da placenta com a idade gestacional, foi criado gráfico de dispersão, sendo o ajuste realizado pelo coeficiente de determinação (R²). RESULTADOS: A média do volume da placenta variou de 4,6 cm³ (2,6-8,6 cm³) a 28,9 cm³ (11,4-66,9 cm³). O volume da placenta (VP) se mostrou altamente correlacionado com a idade gestacional (IG), sendo o melhor ajuste com a regressão exponencial [VP = exp(0,582 × IG + 0,063); R² = 0,82]. CONCLUSÃO: Valores de referência para o volume da placenta no primeiro trimestre de gestação utilizando o método XI VOCAL foram determinados.

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.

Reference range of embryo volume by 3-D sonography using the XI VOCAL method at 7 to 10 + 6 weeks of pregnancy.

We sought to establish normative data for three-dimensional ultrasound (3DUS) first-trimester embryonic volume using the extended imaging virtual organ computer-aided analysis (XI VOCAL) technique. This cross-sectional study involved 64 normal pregnancies at 7 to 10 + 6 weeks' gestation. Embryonic volume was obtained on 3DUS using the XI VOCAL technique with manual outline of 10 sequential planes. The mean, median, standard deviation, and maximum and minimum values were obtained for each week calculated. Polynomial regression models adjusted by the determination coefficient (R(2)) were created to assess the correlation between embryonic volume and gestational age (GA) and crown rump length (CRL). The intraclass correlation coefficient (ICC) was used to calculate inter- and intraobserver reproducibility. Mean embryonic volume went from 0.20 cm(3) (range 0.10 to 0.89 cm(3)) to 5.12 cm(3) (range 2.90 to 5.98 cm(3)). Embryonic volume was strongly correlated with GA (R(2) = 0.84) and with CRL (R(2) = 0.87). There was a good inter- and intraobserver reproducibility of embryonic volume with ICC = 0.999 and 0.995, respectively. Reference range for 3DUS first-trimester embryonic volume using the XI VOCAL technique were generated for pregnancies at 7 to 10 + 6 weeks, with high inter- and intraobserver reproducibility.

Comparison of gestational sac volume by 3D-sonography using planimetric, virtual organ computer-aided analysis and extended imaging virtual organ computer-aided analysis methods between 7 and 11 weeks of pregnancy.

OBJECTIVE: To compare different three-dimensional (3D) methods in the assessment of gestational sac volume (GSV). DESIGN: Cross-sectional study involving 74 normal pregnancies between 7 and 11 weeks. SETTING: Department of Obstetrics, São Paulo Federal University (UNIFESP). METHODS: GSV was measured through 3D ultrasound using the planimetric, virtual organ computer-aided analysis (VOCAL) and extended imaging virtual organ computer-aided analysis (XI VOCAL) methods. The planimetric method used a sequence of adjacent planes that are 3 mm thick. For the VOCAL methods, six adjacent planes and a 30 degrees rotation were used. A total of 15 adjacent planes were used for the XI VOCAL method. Regression models with a determination coefficient (R(2)) were created to assess the correlation between GSV and gestational age (GA). Intraclass correlation coefficient (ICC) and Bland-Altman graphs were used to assess the correlation between the three methods and ANOVA was used to compare means. RESULTS: All three methods showed a correlation between GSV and GA (R(2) = 0.65 for XI VOCAL, R(2) = 0.65 for planimetric and R(2) = 0.66 for VOCAL). There was a strong correlation between the three methods (XI VOCAL vs. planimetric ICC = 0.995; XI VOCAL vs. VOCAL ICC = 0.998 and planimetric vs. VOCAL ICC = 0.995) without any significant differences according to the Bland-Altman graphs or ANOVA (p < 0.002). CONCLUSIONS: The three 3D ultrasound methods used for GSV assessment between 7 and 11 weeks are concordant. These methods can be used interchangeably during the first trimester of pregnancy to measure GSV.

Nomogram of amniotic fluid volume at 7 to 10+6 weeks of pregnancy by three-dimensional ultrasonography using the rotational method (VOCAL).

PURPOSE: To establish normative data for amniotic fluid volume (AFV) between 7 and 10+6 weeks gestation using three-dimensional ultrasonography (3DUS). METHODS: A cross-sectional study involving 74 normal pregnancies was performed to assess AFV. All measurements were performed using an endocavitary volumetric transducer. The VOCAL (virtual organ computer-aided analysis) method was used for volumetric calculations, with a 30 degrees rotation angle. The AFV was obtained subtracting the embryonic volume from the amniotic sac volume. To analyze the correlation between AFV and gestational age, regression models were constructed and adjustments were made using the determination coefficient (R2). The following AFV values were obtained for each week: mean, median, standard deviation, minimum and maximum. The method proposed by Royston and Wright was used to calculate the reference intervals according to crown-rump length (CRL). RESULTS: Mean AFV increased from 3.97 cm3 (range 1.17-10.97 cm3) at 7 to 7+6 weeks to 23.33 cm3 (ranging from 11.93 to 32.41 cm3) at 10 to 10+6 weeks of pregnancy. There was a significant correlation between AFV and gestational age (R2=0.635) and between AFV and CRL (R2=0.756). Mean AFV increased from 7.81 cm3 (ranging from 0.18 to 15.43 cm3) to 50.28 cm3 (range 16.49-84.07 cm3) for CRL between 12 and 40 mm. CONCLUSIONS: Reference limits for AFV using 3DUS were generated for pregnancies between 7 and 10+6 weeks according to CRL.

Correlação do volume da vesícula vitelínica obtida por meio da ultrassonografia tridimensional com a idade gestacional entre a 7ª e a 10ª semanas usando o método multiplanar / Correlation of yolk sac volume obtained by three-dimensional ultrasonography with the gestational age at 7-10 weeks utilizing the multiplanar method

OBJETIVO: Avaliar a correlação do volume da vesícula vitelínica aferida por meio da ultrassonografia tridimensional com a idade gestacional entre a 7ª e a 10ª semanas. MATERIAIS E MÉTODOS: Realizou-se um estudo do tipo corte transversal envolvendo 72 gestantes normais entre a 7ª e a 10ª semanas de gestação. Para o cálculo do volume da vesícula vitelínica, utilizou-se o método multiplanar com intervalo de 1,0 mm entre os planos. Para o volume da vesícula vitelínica foram determinadas médias, medianas, desvios-padrão e valores máximo e mínimo. Para avaliar a correlação entre o volume da vesícula vitelínica e a idade gestacional, foram criados modelos de regressão, sendo os ajustes realizados pelo coeficiente de determinação (R²). RESULTADOS: O volume da vesícula vitelínica (VV) mostrou-se fracamente correlacionado com a idade gestacional (IG), melhor representado pela regressão quadrática, representada pela equação: volume VV = 0,9757 - 0,2499 × IG + 0,0172 × IG² (R² = 0,234). O volume médio da vesícula vitelínica variou de 0,07 cm³ (0,02-0,11) a 0,20 cm³ (0,02-0,74) entre a 7ª e a 10ª semanas de gestação, com média de 0,11 cm³ (± 0,10 cm³). CONCLUSÃO: O volume da vesícula vitelínica correlacionou-se fracamente com a idade gestacional.

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.

Embryo vascularization by three-dimensional power Doppler ultrasonography at 7-10 weeks of pregnancy.

AIM: Assess vascular indices of 7-10 week embryos using three-dimensional power Doppler (3DPD) and correlate them with the crown-rump length (CRL). METHODS: This cross-sectional study included 65 healthy pregnancies between 7 and 10 weeks. The three-dimensional volume of the embryo was obtained using an endocavitary volumetric transducer and the VOCAL (Virtual Organ Computer-aided Analysis) method, with a 12 degree rotation angle and 15 sequential planes. The vascularization (VI), flow (FI) and the vascular and flow (VFI) indices were obtained using 3DPD and the mean, median, standard deviation, maximum and minimum values were calculated for each gestational age. Pearson's correlation coefficient (r) was used to evaluate the correlation between vascular indices and CRL. RESULTS: The VI ranged from 0.77 to 41.67, mean 14.68 (+/-8.60), the FI went from 25.71 to 139.50, mean 90.61 (+/-21.51) and the VFI from 0.20 to 81.57, mean 15.69 (+/-12.42). The correlation between CRL and all 3D power Doppler vascular indices was low (VI - r=-0.073, P=0.566; FI - r=0.173, P=0.168 and VFI - r=-0.004, P=0.974). CONCLUSION: 3D power Doppler vascular indices in 7-10 week embryos do not correlate with CRL.

Gestational sac volume by 3D-sonography at 7-10 weeks of pregnancy using the VOCAL method.

PURPOSE: Establish normative data for gestational sac volume (GSV) between 7 and 10 weeks gestation using three-dimensional ultrasonography (3DUS). METHODS: A cross-sectional study involving 74 normal pregnancies was performed to assess GSV between 7 and 10 weeks gestation. All measurements were performed using an endocavitary volumetric transducer. The virtual organ computer-aided analysis (VOCAL) method was used for volumetric calculations, with a 30 degrees rotation angle. To analyze the correlation between GSV and gestational age, regression models were constructed and adjustments were made using the determination coefficient (R (2)). For each week the mean, median, standard-deviation, minimum and maximum GSV values were calculated. The method proposed by Royston and Wright was used to calculate the reference intervals according to crown-rump length (CRL). The interclass correlation coefficient (ICC) and Bland-Altman graph were used to evaluate intraobserver variability. RESULTS: There was a high correlation between GSV and gestational age (R (2) = 0.816). Mean GSV increased from 8.50 cm(3) at 7 weeks to 44.35 cm(3) at 10 weeks. There was also a significant correlation between GSV and CRL (R (2) = 0.693) with mean GSV increasing from 5.00 to 50.28 cm(3) for CRL between 9 and 40 mm. Intraobserver variability was excellent with an ICC = 0.9997 (95% CI, 0.9994-0.9998), with an average difference between measurements of 0.5 cm(3). CONCLUSIONS: There is a correlation between GSV and CRL and this is a reproducible first trimester parameter. Reference limits for GSV using 3DUS were generated for pregnancies between 7 and 10 weeks.

[Embryo volume estimated by three-dimensional ultrasonography at seven to ten weeks of pregnancy]. / Volume do embrião estimado pela ultra-sonografia tridimensional entre a sétima e a décima semana de gestação.

PURPOSE: to evaluate the embryo's volume (EV) between the seventh and the tenth gestational week, through tridimensional ultrasonography. METHODS: a transversal study with 63 normal pregnant women between the seventh and the tenth gestational week. The ultrasonographical exams have been performed with a volumetric abdominal transducer. Virtual Organ Computer-aided Analysis (VOCAL) has been used to calculate EV, with a rotation angle of 12 masculine and a delimitation of 15 sequential slides. The average, median, standard deviation and maximum and minimum values have been calculated for the EV in all the gestational ages. A dispersion graphic has been drawn to assess the correlation between EV and the craniogluteal length (CGL), the adjustment being done by the determination coefficient (R(2)). To determine EV's reference intervals as a function of the CGL, the following formula was used: percentile=EV+K versus SD, with K=1.96. RESULTS: CGL has varied from 9.0 to 39.7 mm, with an average of 23.9 mm (+/-7.9 mm), while EV has varied from 0.1 to 7.6 cm(3), with an average of 2.7 cm(3) (+/-3.2 cm(3)). EV was highly correlated to CGL, the best adjustment being obtained with quadratic regression (EV=0.2-0.055 versus CGL+0.005 versus CGL(2); R(2)=0.8). The average EV has varied from 0.1 (-0.3 to 0.5 cm(3)) to 6.7 cm(3) (3.8 to 9.7 cm(3)) within the interval of 9 to 40 mm of CGL. EV has increased 67 times in this interval, while CGL, only 4.4 times. CONCLUSIONS: EV is a more sensitive parameter than CGL to evaluate embryo growth between the seventh and the tenth week of gestation.

Yolk sac volume assessed by three-dimensional ultrasonography using the VOCAL method.

OBJECTIVES: Establish normative data for yolk sac volume (YSV) at 7-10 weeks of gestation assessed by transvaginal three-dimensional ultrasonography (3D-US) using the VOCAL method and analyze its correlation with gestational age (GA) and crown-rump length (CRL). METHODS: A cross-sectional study involving 62 normal pregnancies was performed to assess YSV from 7 to 10 weeks of gestational age. An endocavitary volumetric transducer (3D5-8EK) was used for all measurements. The VOCAL (Virtual Organ Computer-aided AnaLysis) method with a 30 degrees rotation angle was used for volumetric calculations. Regression models were constructed to analyze the correlation between YSV and GA or CRL The mean, standard deviation, median, minimum and maximum values were calculated for each gestational age. RESULTS: There was a poor correlation between YSV and GA or CRL. The quadratic regression was the model that best expressed the correlation between these variables: R2=0.188 for GA and R2=0.203 for CRL. The mean YSV went from 0.063 cm(3) (95% CI: 0.047; 0.080) at 7 weeks to 0.164 cm3 (95% CI 0.095; 0.232) at 10 weeks. CONCLUSION: Reference limits were generated for first trimester YSV using 3D-US. There was a poor correlation between YSV and GA or CRL.

Prenatal diagnosis of Ebstein's anomaly using spatio-temporal image correlation (STIC) and inversion mode.

BACKGROUND: Ebstein's anomaly is a rare cardiac defect where the septal and posterior leaflets are displaced, towards the right ventricle. The leaflets are dysplastic and stuck to the ventricular wall. Its antenatal diagnosis is usually made through bidimensional echocardiography, which also has prognostic value. Recently, the technological breakthrough of three-dimensional ultrasound (3D-US) offered new diagnostic tools for congenital heart defects, less dependent on the ultrasonographer experience, when compared to two-dimensional ultrasound (2D-US). The spatio-temporal image correlation (STIC) technique allows the acquisition of the fetal heart volume and its structures as a 4D cineloop sequence showing the complete cardiac cycle. Inversion mode is a new image analysis tool for the examination of fluid-filled fetal structures that inverts the gray scale. CASE REPORT: We present a case of Ebstein's anomaly diagnosed at 26 weeks of pregnancy through bidimensional echocardiography. We emphasize its main findings in 3D-US using the STIC and inversion mode techniques.

Placenta: angiogenesis and vascular assessment through three-dimensional power Doppler ultrasonography.

The placenta is fundamental for fetal development. It combines the functions of an endocrine organ, kidneys, lungs and intestines, purifying catabolites, oxygenating and nourishing the conceptus. Its fetal portion is the largest part develops from the chorionic sac. The maternal portion, which is smaller, is originated in the endometrium, more specifically in the decidua basalis. The placenta starts its function closer to the fourth week of gestation, when anatomical arrangements for the physiological exchanges are already established. The circulatory function of the placenta appears at an early stage of embryo-placental development and it is strongly related to fetal growth, to the placental size and to uterine and umbilical blood flows. Therefore, an adequate placental angiogenesis is critical for the establishment of a normal placental vascularization with consequent normal development of the fetus. In this review article, the authors discuss about placental ontogeny, focusing on the main aspects of its normal development, and about the recent advances in ultrasonography for the study of the vascular architecture of the placenta through three-dimensional power Doppler ultrasonography.

Volume do embrião estimado pela ultra-sonografia tridimensional entre a sétima e a décima semana de gestação / Embryo volume estimated by three-dimensional ultrasonography at seven to ten weeks of pregnancy

OBJETIVO: avaliar a evolução do volume do embrião (VE) entre a sétima e a décima semana de gestação por meio da ultra-sonografia tridimensional. MÉTODOS: realizou-se um estudo de corte transversal com 63 gestantes normais entre a sétima e a décima semana. Os exames ultra-sonográficos foram realizados por meio de um transdutor endocavitário volumétrico. Para o cálculo do VE, utilizou-se o método VOCAL (Virtual Organ Computer-aided Analysis) com ângulo de rotação de 12º, com delimitação de 15 planos seqüenciais. Para o VE foram calculadas médias, medianas, desvios padrão e valores máximo e mínimo em todas as idades gestacionais. Para se avaliar a correlação entre o VE e o comprimento cabeça-nádega (CCN) foi criado gráfico de dispersão, sendo o ajuste realizado pelo coeficiente de determinação (R²). Para se determinarem intervalos de referência do VE em função do CCN, utilizou-se a seguinte fórmula: percentil =VE+K versus dp, com K=1,96. RESULTADOS: o CCN variou de 9,0 a 39,7 mm, com média de 23,9 mm (±7,9 mm), enquanto o VE variou de 0,1 a 7,6 cm³, com média de 2,7 cm³ (±3,2 cm³). O VE foi altamente correlacionado com o CCN, sendo que o melhor ajuste foi obtido com regressão quadrática (VE=0,165 - 0,055 x CCN + 0,005 x CCN²; R²=0,853). O VE médio variou de 0,1 (-0,3 a 0,5 cm³) a 6,7 cm³ (3,8 a 9,7 cm³) no intervalo de 9 a 40 mm do CCN. Neste intervalo o VE aumentou 67 vezes, enquanto o CCN aumentou apenas 4,4 vezes. CONCLUSÕES: o VE é um parâmetro mais sensível que o CCN para avaliar o crescimento embrionário entre a sétima e a décima semana de gestação.

PURPOSE: to evaluate the embryo's volume (EV) between the seventh and the tenth gestational week, through tridimensional ultrasonography. METHODS: a transversal study with 63 normal pregnant women between the seventh and the tenth gestational week. The ultrasonographical exams have been performed with a volumetric abdominal transducer. Virtual Organ Computer-aided Analysis (VOCAL) has been used to calculate EV, with a rotation angle of 12º and a delimitation of 15 sequential slides. The average, median, standard deviation and maximum and minimum values have been calculated for the EV in all the gestational ages. A dispersion graphic has been drawn to assess the correlation between EV and the craniogluteal length (CGL), the adjustment being done by the determination coefficient (R²). To determine EV's reference intervals as a function of the CGL, the following formula was used: percentile=EV+K versus SD, with K=1.96. RESULTS: CGL has varied from 9.0 to 39.7 mm, with an average of 23.9 mm (±7.9 mm), while EV has varied from 0.1 to 7.6 cm³, with an average of 2.7 cm³ (±3.2 cm³). EV was highly correlated to CGL, the best adjustment being obtained with quadratic regression (EV=0.2-0.055 versus CGL+0.005 versus CGL²; R²=0.8). The average EV has varied from 0.1 (-0.3 to 0.5 cm³) to 6.7 cm³ (3.8 to 9.7 cm³) within the interval of 9 to 40 mm of CGL. EV has increased 67 times in this interval, while CGL, only 4.4 times. CONCLUSIONS: EV is a more sensitive parameter than CGL to evaluate embryo growth between the seventh and the tenth week of gestation.