Luciano Marcondes Machado Nardozza

Fetal growth restriction: current knowledge

BackgroundFetal growth restriction (FGR) is a condition that affects 5–10% of pregnancies and is the second most common cause of perinatal mortality. This review presents the most recent knowledge on FGR and focuses on the etiology, classification, prediction, diagnosis, and management of the condition, as well as on its neurological complications.MethodsThe Pubmed, SCOPUS, and Embase databases were searched using the term “fetal growth restriction”.ResultsFetal growth restriction (FGR) may be classified as early or late depending on the time of diagnosis. Early FGR (<32 weeks) is associated with substantial alterations in placental implantation with elevated hypoxia, which requires cardiovascular adaptation. Perinatal morbidity and mortality rates are high. Late FGR (≥32 weeks) presents with slight deficiencies in placentation, which leads to mild hypoxia and requires little cardiovascular adaptation. Perinatal morbidity and mortality rates are lower. The diagnosis of FGR may be clinical; however, an arterial and venous Doppler ultrasound examination is essential for diagnosis and follow-up. There are currently no treatments to control FGR; the time at which pregnancy is interrupted is of vital importance for protecting both the mother and fetus.ConclusionEarly diagnosis of FGR is very important, because it enables the identification of the etiology of the condition and adequate monitoring of the fetal status, thereby minimizing risks of premature birth and intrauterine hypoxia.

Heart stroke volume, cardiac output, and ejection fraction in 265 normal fetus in the second half of gestation assessed by 4D ultrasound using spatio-temporal image correlation

Objectives. The aim of this study was to establish nomograms for fetal stroke volume (SV), cardiac output (CO), and ejection fraction (EF) using four-dimensional ultrasound with spatio-temporal image correlation (STIC) modality. Methods. The fetal heart was scanned using STIC modality, starting with classic four-chamber view plane, during fetal quiescence with abdomen uppermost, at an angle of 20–30°, without color Doppler flow mapping. In post-processing virtual organ, computer-aided analysis technique was used to obtain a sequence of six sections of each ventricular volume in end-systolic volume (ESV) and end-diastolic volume (EDV). The SV (SV = EDV–ESV), CO (CO = SV × fetal heart rate), and EF (EF = SV/EDV) for each ventricle were then calculated. Intra- and interobserver agreement were then calculated. Results. Two hundred sixty-five fetuses, ranging in gestational age (GA) from 20 to 34+6 weeks, were included in the study. The left and right SV and CO increased exponentially with gestation and EF remained fairly stable through gestational. Mean left and right SV increased from 0.211 ml and 0.220 ml at 20 weeks to 1.925 ml and 2.043 ml, respectively, at 34 weeks. Mean left and right CO increased from 30.25 ml/min and 31.52 ml/min at 20 weeks to 268.49 ml/min and 287.80 ml/min, respectively, at 34 weeks. Both left and right mean EF remained constant at around 0.63 with advancing GA. Nomograms were created for LSV, RSV, LCO, RCO, LEF, and REF vs. gestational age. Intra- and interobserver agreement reached 95%. Conclusions. Four-dimensional ultrasound using STIC represents a simple and reproducible method for estimating fetal cardiac function. STIC seems to overcome many of the pitfalls of conventional ultrasound methods and has the potential to become the method of choice.

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.

Reliability and Validity of In Vitro Volume Calculations by 3-Dimensional Ultrasonography Using the Multiplanar, Virtual Organ Computer-Aided Analysis (VOCAL), and Extended Imaging VOCAL Methods

Objective. The purpose of this study was to assess the reliability and validity of in vitro volume calculations by 3‐dimensional ultrasonography. Methods. This observational study was performed by 2 examiners to obtain volumes of 3 objects of different shapes and sizes filled with ultrasound gel and immersed in water. The examiners used the multiplanar (5‐mm interval), virtual organ computer‐aided analysis (VOCAL, 30°) and extended imaging (XI) VOCAL (5, 10, 15, and 20 planes) methods to estimate the volumes of each object. A paired Student t test (P) and intraclass correlation coefficients (ICCs) were used to assess reproducibility of the methods. Validity was assessed comparing the percent differences between the estimated and the real volumes using the P value, mean differences, and ICC for each method. Results. All methods were highly reliable and valid. There were no significant differences in interobserver variability; there was a strong interobserver correlation. There were no significant differences in the percent differences between the estimated and real volumes of the objects using the 3 methods. The XI VOCAL method was superior to the multiplanar and VOCAL methods in the measurement of irregularly shaped objects. The XI VOCAL method with 10 planes estimated volumes closest to the real volumes. Conclusions. All 3 methods were reliable and valid; however, XI VOCAL was superior to the other methods in the measurement of irregularly shaped objects.

XI VOCAL (eXtended Imaging VOCAL): a new modality for three-dimensional sonographic volume measurement

AbstractIntroductionThe important technological evolutions that three-dimensional ultrasonography devices have gone through in the last years have brought great benefits for the volumetric measurement of fetal organs and structures. In clinical practice, three-dimensional volumetry has helped to identify abnormalities in fetal compartment and other related organs, assisting in the diagnosis and risk estimation of several pathological conditions in fetal medicine.AimThe authors describe a new methodology for volumetric calculation through three-dimensional ultrasonography called eXtended Imaging VOCAL (XI VOCAL), which is part of the software Three-dimensional eXtended Imaging (3DXI)TM. This software virtualizes real organs, by analyzing the volume through a diagram of slice sections (Multi-slice view) that simultaneously shows a sequence of images in parallel planes, and establishes the volume of the organ. Because of the importance of accurate volumetric measurements in obstetric ultrasonography, a new method allowing this measurement should be regarded as of great interest.

The cross-sectional area of umbilical cord components in normal pregnancy

Objective: To determine the normal cross‐sectional areas of the umbilical vein, umbilical artery, and Wharton jelly in healthy pregnancies, and correlate the obtained values with fetal anthropometric parameters. Methods: A cross‐sectional study was performed with 312 women between the 24th and 39th weeks of a normal pregnancy. The cross‐sectional areas of umbilical cord vessels were measured at the junction of the cord and fetal abdomen, and the values were subtracted from the total cord cross‐sectional area to assess the cross‐sectional area of the Wharton jelly. The anthropometric parameters analyzed were biparietal diameter, head circumference, femur length, and estimated fetal weight, and the Spearman correlation was used to assess the correlation between the cross‐sectional areas of umbilical cord components and fetal anthropometric parameters. A polynomial regression analysis was performed to identify the curves that best adjusted to mean and standard deviation according to gestational age. Results: A statistically significant correlation was observed between the cross‐sectional areas of cord components and fetal anthropometric parameters (P < 0.001) as well as gestational age (P < 0.001). Conclusions: Reference measurements of the cross‐sectional areas of umbilical cord components are important tools in the assessment of fetal growth.

Evolution of 3-D power Doppler indices of fetal brain in normal pregnancy.

We assessed the vascular indices of the anterior territory of the middle cerebral artery (MCA) in normal pregnancies using 3-D power Doppler (3DPD). A cross-sectional study was carried out on 90 normal pregnancies between 24 and 35 weeks. All examinations were performed by a single operator using a volumetric transducer. The anterior territory of the MCA was scanned and the volumes were captured using 3DPD. The sphere mode of the VOCAL program was used to calculate the following vascular indices: vascularization index (VI), flow index (FI) and vascularization and flow index (VFI). Models of polynomial regression and Pearsons correlation coefficient were used to evaluate the correlation between gestational age (GA) and the vascular indices. The 3DPD vascular indices had a low correlation with gestational age (VI - r = 0.324, p = 0.002; FI - r = 0.375, p < 0.001; VFI - r = 0.374, p < 0.001). There was a low correlation between GA and the 3DPD vascular indices of the anterior territory of the MCA.

Reference Range of Fetal Renal Volume by Three-Dimensional Ultrasonography Using the Vocal Method

Objective: To establish reference values for fetal renal volume by three-dimensional sonography using the VOCAL (Virtual Organ Computer-Aided Analysis) method. Methods: This prospective longitudinal study involved 57 healthy pregnant women who were examined between 24 and 34 weeks of pregnancy. Each fetal kidney was evaluated separately using the VOCAL method with a 30° rotation angle. For each gestational age, the following measures were obtained for the right and left kidneys: mean, standard deviation, minimum and maximum values, and the 5th, 10th, 25th, 50th, 75th and 90th percentiles. Polynomial regression models were constructed to assess the relationship between renal volume and gestational age, adjusted by the determination coefficient (R2). The Wilcoxon test was used to evaluate the concordance between the right and left renal volumes. Bland-Altman graphs were used to assess intra- and inter-observer variability. Results: The right renal volume increased from 4.5 ± 1.3 cm3 at 24 weeks to 12.1 ± 1.5 cm3 at 34 weeks. The left renal volume increased from 4.6 ± 0.8 cm3 at 24 weeks to 11.9 ± 1.1 cm3 at 34 weeks. There was a strong correlation between both the right and left renal volumes and gestational age (R2 = 0.975 and 0.970, respectively). There were no significant differences between the right and left renal volumes. The mean difference between repeated measures by the same examiner was –0.07 cm3 (–0.88 to 0.75) for the right kidney and –0.21 cm3 (–0.95 to 0.75) for the left kidney. The mean difference between repeated measures obtained by two different examiners was –0.07 cm3 (–1.25 to 1.12) for the right kidney and 0 cm3 (–1.53 to 1.53) for the left kidney. Conclusion: Reference values were generated for fetal renal volume assessed by three-dimensional ultrasonography using the VOCAL method.

Evaluation of Placental Volume at 7–10 + 6 Weeks of Pregnancy by 3D-Sonography

The aim of the study was to establish normative data for placental volume (PV) at 7-10+6 weeks of gestation using three-dimensional ultrasound (3DUS). The cross-sectional study involved 70 healthy pregnancies between 7 and 11 weeks. The VOCAL (Virtual Organ Computer-aided Analysis) method with a 30 degrees rotation angle and six planes was used for volumetric calculations. Regression models were constructed to assess the correlation between PV and crown-rump length (CRL) adjusted by the determination coefficient (R2). The method proposed by Royston and Wright was used to establish the 2.5th; 10th; 50th; 90th and 97.5th percentiles (percentile=mean+KxSD). The intraclass correlation coefficient (ICC), Bland-Altman graphs and Students paired t-tests were used to assess intra- and interobserver variability. PV ranged from 1.7 to 42.6 cm3, with a mean of 13.6cm3 (+/-9.4cm3). There was a strong correlation between PV and CRL; the exponential equation was the model that best expressed the correlation between them (R2=0.76). For CRL between 9 and 40 mm, the mean PV increased 10.5 times, while CRL increased only 4.4 times. Inter- and intraobserver correlation were excellent (ICC=0.979 and 0.971, respectively). Bland-Altman graphs indicated a good reproducibility with a mean intraobserver and interobserver difference of 0.2 cm3 (95% CI: -0.7-1.2cm3) and -0.2cm3 (95% CI: -1.3-0.9cm3), respectively. Reference limits were generated for first trimester PV assessed by 3DUS using the VOCAL method. There is a strong correlation between PV and CRL. Placental volume obtained through this method was highly reproducible.

Placental blood flow measured by three-dimensional power Doppler ultrasound at 26 to 35 weeks gestation in normal pregnancies.

Objective. To evaluate placental vascular indices, in pregnancies between 26 and 35 weeks, using three-dimensional power Doppler (3DPD) ultrasound and the effect of placental location on these indices. Methods. This was a cross-sectional study involving 283 patients. The placental vascularization index (VI), flow index (FI) and vascularization and flow index (VFI) was obtained using the VOCAL program. Pearsons linear correlation coefficient was used to assess the relationship between gestational age and these indices. Students parametric t-test and Levenes test were used to analyse the results between VI, FI and VFI and placental location. Results. There was no linear correlation between gestational age (GA) and VI (p = 0.390) and VFI (p = 0.053). Only the FI presented a significant linear correlation (p = 0.004), with a slow increase according to GA. It was possible to construct a reliable nomogram only for this index. There were no significant differences in the VI, FI and VFI according to placental location (p = 0.323, 0.172 and 0.120, respectively). Conclusion. Placental FI assessed by 3DPD increases progressively and significantly between 26 and 35 weeks. Placental location has no influence on the three vascular indices studied. The FI reference values obtained in this study can be used as a parameter for future investigations on placental vascularization using 3DPD.