Assessment of early chorionic circulation by three-dimensional power Doppler

Assessment of uteroplacental vascularisation in early first-trimester pregnancy with contrast-enhanced ultrasound and 3D power Doppler angiography: protocol for a prospective, cross-sectional, multicentre and non-randomised open study ("HOPE Study")

INTRODUCTION

Knowledge about the mechanisms leading to the establishment of uteroplacental vascularisation is inadequate, and some of what has been thought to be known for decades has recently been challenged by showing that the intervillous space, the major area of maternal-fetal exchange, appears to be perfused by maternal blood at as early as 6 weeks of gestation. The vascular flow then seems relatively constant until 13 weeks when it appears to increase suddenly.

OBJECTIVES

The principal objective is to quantify the perfusion of the intervillous space by contrast-enhanced ultrasonography (CEUS) during the first-trimester at three different gestational ages (8, 11 and 13 weeks). The secondary objectives are to: (1) describe the indicators of vascularisation of the placenta (intervillous space) and the myometrium at the three gestational ages, measured by CEUS and three-dimensional power Doppler (3DPD) angiography; (2) compare the diagnostic performance of CEUS and 3DPD for the demonstration and quantification of uteroplacental vascularisation and (3) establish a biological collection of placentas to increase knowledge about placental development and functions during pregnancy.

METHODS AND ANALYSIS

This is a prospective, cross-sectional, multicentre and non-randomised open study. We will include 42 women with ongoing pregnancy and divided into three groups of gestational ages (ie, 14 women by per group): 8, 11 and 13 weeks of gestation. 3DPD and then CEUS will be performed and the data about the perfusion kinetics and the 3DPD indices will be calculated and then compared with each other and for each gestational age.

ETHICS AND DISSEMINATION

The appropriate French Ethics Committee Est III approved this study and the related consent forms on 5 April 2016, and the competent authority (Agence Nationale de Sécurité du Médicament et des Produits de Santé) authorised the study on 21 June 2016. The results of this study will be published in a peer-reviewed journal and will be presented at relevant conferences.

TRIAL REGISTRATION NUMBERS

ClinicalTrials.gov registry (NCT02884297); EudraCT registry (2015-005655-27).

Can early ultrasonography explain the lower miscarriage rates in twin as compared to singleton pregnancies following assisted reproduction?

Objective:

To compare first trimester 2D conventional and 3D power Doppler angiography measures in twins and singletons following assisted reproduction.

Methods:

We prospectively evaluated 50 singleton and 47 twin pregnancies that eventually ended in live births. Patients were recruited from a single assisted reproductive technology (ART) center with standard treatment protocols. Obstetric ultrasound was performed at 8–9 weeks +6 days. Intervillous flow, uteroplacental circulation and uterine artery pulsatility (PI) and resistance index (RI) using two-dimensional (2D) ultrasound examination were evaluated. Using three-dimensional (3D) power Doppler angiography, placental volume and the 3D power Doppler indices from the intervillous and uteroplacental circulation were calculated.

Results:

Demographic and cycle characteristics were similar in mothers of singletons and twins. Placental volume was significantly (1.6-fold) larger in twins. Vascular density and blood perfusion in the intervillous space were lower in twins. The comparison of the other parameters did not show significant differences between singletons and twins.

Conclusion:

The data confirm the larger placental volume in twins, denoting a probable higher production of placental hormones that would support an early twin pregnancy. The lower vascular density and blood perfusion in the intervillous space in twins may also confer a reproductive advantage to them.

Evaluation of placental vascularization indices in monochorionic diamniotic and dichorionic diamniotic twin pregnancies

OBJECTIVES

We aimed to investigate and compare placental vascularization indices between monochorionic-diamniotic, dichorionic-diamniotic normal twin pregnancies, and normal singular pregnancies. We hypothesized that there is correlation between placental three-dimensional power Doppler vascularization indices and birth weight in case of twin pregnancies, and that normal singular pregnancies have higher placental vascularization indices than normal twin pregnancies.

STUDY DESIGN

Placental three-dimensional power Doppler vascularization indices, such as vascularization index, flow index, and vascularization-flow index were measured in monochorionic-diamniotic (N = 15) and dichorionic-diamniotic (N = 36) normal twin pregnancies, and in normal singular (N = 109) pregnancies. Correlations were analyzed between vascularization indices, and birth weight, APGAR score, umbilical pH, umbilical venous bicarbonate, lactate, and base excess.

RESULTS

Vascularization indices and birth weight were significantly (p < 0.01) higher in normal singular gestations (vascularization index = 10.36, flow index = 46.08, vascularization-flow index = 4.08, average birth weight = 3377 g at 38.2 weeks average gestational age) compared to monochorionic-diamniotic and dichorionic-diamniotic normal twin pregnancies. No significant differences were found in vascularization indices between monochorionic-diamniotic and dichorionic-diamniotic normal twins. There were no significant differences in APGAR score, umbilical pH, umbilical venous bicarbonate, lactate, and base excess between groups examined (p < 0.01). We found strong linear correlations between placental vascularization indices and birth weight in both twin groups.

CONCLUSION

Placental three-dimensional power Doppler vascularization indices seem appropriate for predicting birth weight in monochorionic-diamniotic and dichorionic-diamniotic normal twin pregnancies. Our pilot study revealed reference values for vascularization indices in case of twin pregnancies examined.

Use of placental vascularization indices and uterine artery peak systolic velocity in early detection of pregnancies complicated by gestational diabetes, chronic or gestational hypertension, and preeclampsia at risk

AIM

We aimed to investigate correlations between uterine artery peak systolic velocity (AUtPSV), and placental vascularization in groups of normal blood pressure (NBP) and hypertensive disorders of pregnancy (chronic hypertension (CHT), gestational hypertension (GHT) and preeclampsia (PE)) alone or in combination with gestational diabetes mellitus (GDM), and hypothesized that AUtPSV rises when GDM complicates pregnancy hypertension.

METHODS

Placental 3-dimensional power Doppler indices, such as vascularization index (VI), flow index (FI), and vascularization-flow index (VFI), and uterine artery peak systolic velocity (AUtPSV) were measured in CHT (N=43), CHT+GDM (N=15), GHT (N=57), GHT+GDM (N=23) and PE (N=17) pregnancies, and compared to NBP (N=109). Correlations were analyzed between vascularization indices, AUtPSV, pregestational BMI and adverse pregnancy outcome rates.

RESULTS

In our results VI was higher in CHT (P=0.010), while FI was lower in CHT (P=0.009), GHT and PE (P=0.001) compared to NBP. In case of VFI, significant difference was found between CHT and GHT (P=0.002), and NBP and PE (P=0.001). FI was found prognostic for umbilical pH and neonatal birth weight. Pre-gestational BMI was significantly higher in GHT+GDM compared to GHT, and in CHT+GDM compared to the CHT group. As for AUtPSV, significant difference was found between NBP and CHT (P=0.012), NBP and CHT+GDM (P=0.045), NBP and GHT+GDM (P=0.007), NBP and PE (P=0.032), and GHT and GHT+GDM (P=0.048) groups.

CONCLUSION

Our study revealed that vascularization indices and AUtPSV show significant differences due to gestational pathology, and can be useful in detection of pregnancies at risk.

Three-dimensional Evaluation of the Placenta: Review of the Literature

The introduction of the three-dimensional (3D) ultrasound made feasible the quantitative and qualitative evaluation of the placenta's characteristics like the volume, the surface rendered imaging, the vascularization and the blood flow. These novel techniques may assist the early detection of pregnancies at high risk for fetal growth restriction (FGR), pre-eclampsia (PET) and pregnancy-induced hypertension (PIH) and help clinicians to detect pregnancies at risk earlier and to assess new therapeutic strategies in order to prevent adverse pregnancy outcomes. However, in this new technique there are still limitations regarding the assessment of the placenta employing 3D ultrasound in everyday clinical practice. In the following article, we perform a review of the literature regarding the importance of 3D evaluation of the placenta in pregnancy.

How to cite this article

Natsis S, Antsaklis P, Antsaklis A, Kurjak A. Three-dimensional Evaluation of the Placenta: Review of the Literature. Donald School J Ultrasound Obstet Gynecol 2013;7(1):73-79.

Placental volume and vascular flow assessed by 3D power Doppler and adverse pregnancy outcomes

OBJECTIVE

To estimate the utility of first-trimester 3D-placental volume and vascular flow indices in the prediction of adverse pregnancy outcomes.

METHODS

A prospective cohort study including women with singleton pregnancies seen between 11 and 14 weeks as part of a screening program for aneuploidy. Placental volume and vascularization indices were obtained using 3D power Doppler imaging and the VOCAL technique. Placental volume (PV), Vascularization Index (VI), Flow Index (FI) and Vascularization Flow Index (VFI) were calculated. The adverse pregnancy outcomes investigated include preeclampsia (PE), gestational hypertension (GH) and small for gestational age (SGA). The predictive ability of each variable was evaluated using receiver-operating characteristic (ROC) curves.

RESULTS

Of 388 women included, PE was seen in 30 (7.7%), GH in 37 (9.0%) and SGA in 31 (8.0%). Placental volume was not significantly different between the pregnancies with adverse outcomes and those without. The mean values of the VI and VFI were significantly lower in the pregnancies that developed PE but not in GH or SGA. The area under the ROC curve for the prediction of PE was 0.71, 0.69 and 0.70 for VI, FI and VFI, respectively.

CONCLUSION

The study confirms lower 3D power Doppler vascular flow indices in pregnancies that develop PE. The discriminatory ability of using these indices alone for predicting PE appears modest.

Intervillous and uteroplacental circulation in normal early pregnancy and early pregnancy loss assessed by 3-dimensional power Doppler angiography

OBJECTIVE

To assess intervillous and uteroplacental circulation in early normal pregnancies and miscarriages.

STUDY DESIGN

One hundred normal pregnancies and 46 delayed miscarriages were evaluated by 3-dimensional vaginal ultrasound and power Doppler angiography. Volumes of the early placenta and the subplacental area were obtained between 5 and 12.6 weeks' gestation. The placental volume, vascularization index, flow index, and vascularization flow index was calculated.

RESULTS

Intraclass correlation coefficients ranged from 0.961 for placental volume to 0.885 for intervillous flow index. Intervillous power Doppler signals were not detected before the sixth week. Placental volume (R(2) = 0.68), intervillous vascularization index (R(2) = 0.30), flow index (R(2) = 0.33) and vascularization flow index (R(2) = 0.35), uteroplacental flow index (R(2) = 0.34), and vascularization flow index (R(2) = 0.17) increase significantly (P < .001) throughout the first trimester of normal pregnancies. Uteroplacental vascularization index was not significantly related to gestational age. Intervillous vasculariztion index, flow index, and vascularization flow index were significantly raised in miscarriages, but there were no significant differences for uteroplacental vascularization index, flow index, or vascularization flow index.

CONCLUSION

Intervillous and uteroplacental blood flow increases throughout the first trimester of normal pregnancies. Intervillous circulation is abnormally increased when a miscarriage is diagnosed.

Is three-dimensional power Doppler ultrasound useful in the assessment of placental perfusion in normal and growth-restricted pregnancies?

OBJECTIVES

To investigate three-dimensional (3D) power Doppler ultrasound indices in the assessment of placental perfusion and their relationship to gestational age (GA), placental position and umbilical artery Doppler flow velocity waveform (FVW) patterns in normal and intrauterine growth-restricted (IUGR) pregnancies.

METHODS

Forty-five pregnant women at 23-37 weeks' gestation were studied, of whom 30 had IUGR and 15 were controls. Nine of the IUGR group had normal umbilical FVWs (NED), nine had abnormal patterns but positive end-diastolic velocities (PED) and 12 had absent or reversed end-diastolic velocities (AED). Placental position was assessed as being posterior, anterior or lateral. 3D power Doppler indices related to placental perfusion (vascularization index (VI), vascularization flow index (VFI) and flow index (FI)) were obtained from five different sampling sites in each placenta.

RESULTS

VI, VFI and FI were not significantly dependent on GA or placental position. VI and VFI were significantly lower in PED and AED cases compared with controls, while FI was reduced in the AED group only. VI and VFI showed high variability between different sampling sites within each placenta, while the variability of FI was much lower.

CONCLUSIONS

3D power Doppler sonography can provide new insights into placental pathophysiology. FI, which identifies the most severe cases of placental impairment, appears to be the most reliable index because of its low intraplacental variability. Further studies are needed to verify its accuracy when applied in clinical practice as a substitute for or an adjunct to umbilical artery Doppler studies.

How useful is 3D and 4D ultrasound in perinatal medicine?

AIM

The purpose of this paper is to review and analyze the published literature on the use of three-dimensional (3DUS) and four-dimensional (4DUS) ultrasound in perinatal medicine.

METHODS

We systematically searched Medline through PubMED (January 2000-January 2006), including EMBASE/Excerpta Medica database as well as the Cochrane Database of Systematic Reviews. The search terms used to identify clinical application of 3DUS and 4DUS studies in perinatal medicine were technical development, special features, and recommendation for fetal imaging, research on 3DUS or 4DUS, and the usage of invasive 3DUS or 4DUS procedures. The reference bibliographies of relevant books were also manually searched for supplementary citations. Inclusion criteria were as follows: (1) studies related to the use of 3DUS or 4DUS in perinatal medicine; (2) full text were available in English; (3) publication format of original scientific articles, case reports, editorials or literature reviews and chapters in the books.

RESULTS

Five hundred and seventy-five articles were identified, and among those, 438 were relevant to this review.

CONCLUSIONS

3DUS and 4DUS provided additional information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical utility of 3DUS and 4DUS for the diagnosis of congenital heart disease, central nervous system (CNS) anomalies and detection of fetal neurodevelopmental impairment assessed by abnormal behavior in high-risk fetuses.

Sonoembryology by three-dimensional ultrasonography: pictorial essay

CONTEXT

Three-dimensional ultrasonography in obstetrics has evolved in the last years, and nowadays it is a methodology that greatly helps prenatal diagnosis. Through its rendering mode it allows the careful evaluation of fetal face and limbs, and in multiplanar mode it allows the assessment of the anatomy through the many possible planes. In the first trimester of gestation, three-dimensional ultrasonography permits the detailed evaluation of embryonic development. Its main advantages over two-dimensional ultrasonography are shorter examination time and the possibility of storage of the volumes for later processing and analysis.

AIM

We present a pictorial essay with normal embryo development in the first trimester of pregnancy by three-dimensional ultrasonography, from the fifth to ninth week.

Three-dimensional transvaginal sonographic diagnosis of early and asymptomatic interstitial pregnancy

CONTEXT

The interstitial gestation is a rare form of tubal pregnancy which is associated with high morbidity. The diagnosis of an interstitial gestation can be reached through a bidimensional transvaginal ultrasonography (2D-TVUS), however, sometimes when making use of this technique it is not possible to appropriately evaluate the position of the gestational sac in relation to the uterine cavity. The three-dimensional transvaginal ultrasonography (3D-TVUS) allows accessibility to plans that the bidimensional does not, thus it makes it possible to reach a more accurate diagnosis and it also allows for an appropriate therapeutic planning.

CASE REPORT

We present a case of interstitial gestation diagnosed in the sixth week in an asymptomatic woman, who had a previous diagnosis of primary infertility. The 2D-TVUS revealed the presence of a gestational sac outside of the uterine cavity; moreover the colored Doppler and the power Doppler indicated a thriving vascular ring. The 3D-TVUS in the surface and transparency mode demonstrated that the gestational sac was located in the interstitial region of the uterine tube, and the niche mode accurately evaluated the relationship between the gestational sac and the uterine cavity. The patient was successfully treated with a local injection of methotrexate guided by a transvaginal ultrasonography. The 3D-TVUS was of great importance to confirm the diagnosis, to allow appropriate therapeutic choices and to decrease the morbidity.

Reproducibility of the study of placental vascularization by three-dimensional power Doppler

AIMS

To assess the reproducibility of 3D power Doppler study of placental vascularization in order to establish its methodological bases for its further application in normal and pathological pregnancies.

METHODS

A prospective study was carried on 30 normal singleton pregnancies from 14 to 40 weeks. To evaluate placental vascularization 3D power Doppler was applied to obtain a "placental biopsy". The spherical volume acquired was analyzed using the VOCAL imaging program. Two consecutive measurements were taken from each patient by a single observer, obtaining a total of 60 datasets. Placental volume (PV), Mean Gray (MG), Vascularization Index (VI), Flow Index (FI) and Vascularization Flow Index (VFI) were calculated. Intra-class correlation coefficient (ICC) and intra-observer agreement was evaluated.

RESULTS

PV and MG presented an ICC of 0.98 and 0.94 respectively, with differences approaching zero. All 3D power Doppler vascular indices (VI, FI and VFI) showed a correlation greater than 0.85, with a better intra-observer agreement for the flow indices (FI and VFI).

CONCLUSIONS

Placental vascular biopsy through 3D power Doppler is a new and simple tool to routinely study placental vascularization in human pregnancy. Our results provide the validation of the technique demonstrating a good reproducibility of the 3D power Doppler parameters when applied to the study of the placental vascular tree in normal pregnancies.

Comprehensive assessment of fetal wellbeing: which Doppler tests should be performed?

PURPOSE OF REVIEW

Doppler applications in pregnancy are expanding exponentially. Flow velocity waveforms provide important information 12 weeks to term, from maternal vessels, placental circulation and fetal systemic vessels, with implications for both mother and fetus. As applications proliferate, awareness of the complexity of fetal and placental circulations, in normal pregnancy and in sequential responses to compromise, has also grown. The necessary data are now available to establish core values in Doppler evaluation for at-risk pregnancies.

RECENT FINDINGS

Uterine arteries depict maternal vascular effects of the invading placenta, predicting the frequency and severity of pre-eclampsia and intrauterine growth restriction. New evidence suggests early treatment based on this principle, significantly reduces these impacts. Umbilical artery Doppler reflects downstream placental vascular resistance, strongly correlated with intrauterine growth restriction and the multisystem effects of placental deficiency. Abnormalities are progressive, with reduction, loss, and finally a reversal of diastolic flow. When umbilical arteries become abnormal, the differentiation of fetal status requires Doppler information from systemic vessels. Middle cerebral artery changes begin when the redistribution of cardiac output reflects rising placental resistance, demonstrating 'brain sparing' when cerebrovascular dilation occurs. In the compromised intrauterine growth retarded fetus, precordial veins illustrate fetal cardiac function, changing as the respiratory status declines. This Doppler information is combined with biophysical profile scoring to determine the need for and timing of intervention.

SUMMARY

Doppler evaluation of at-risk pregnancies provides crucial prognostic and diagnostic detail about placentation and fetal adaptation. What has been research detail is now becoming the standard of care, in comprehensive fetal-maternal assessment.