Clinical profiles of placenta accreta spectrum: the PACCRETA population-based study.

OBJECTIVE: To describe and compare the characteristics of women with placenta accreta spectrum (PAS) and their pregnancy outcomes according to the presence of placenta praevia and a prior caesarean section. DESIGN: Prospective population-based study. SETTING: All 176 maternity hospitals of eight French regions. POPULATION: Two hundred and forty-nine women with PAS, from a source population of 520 114 deliveries. METHODS: Women with PAS were classified into two risk-profile groups, with or without the high-risk combination of placenta praevia (or an anterior low-lying placenta) and at least one prior caesarean. These two groups were described and compared. MAIN OUTCOME MEASURES: Population-based incidence of PAS, characteristics of women, pregnancies, deliveries and pregnancy outcomes. RESULTS: The PAS population-based incidence was 4.8/10 000 (95% CI 4.2-5.4/10 000). After exclusion of women lost to follow up from the analysis, the group with placenta praevia and a prior caesarean included 115 (48%) women and the group without this combination included 127 (52%). In the group with both factors, PAS was more often suspected antenatally (77% versus 17%; P < 0.001) and more often percreta (38% versus 5%; P < 0.001). This group also had more hysterectomies (53% versus 21%, P < 0.001) and higher rates of blood product transfusions, maternal complications, preterm births and neonatal intensive care unit admissions. Sensitivity analysis showed similar results after exclusion of women who delivered vaginally. CONCLUSION: More than half the cases of PAS occurred in women without the combination of placenta praevia and a prior caesarean delivery, and these women had better maternal and neonatal outcomes. We cannot completely rule out that some of the women who delivered vaginally had placental retention rather than PAS; however, we found similar results among women who delivered by caesarean. TWEETABLE ABSTRACT: Half the women with PAS do not have both placenta praevia and a prior caesarean delivery, and they have better maternal outcomes.

Non-invasive evaluation of placental blood flow: lessons from animal models.

In human obstetrics, placental vascularisation impairment is frequent as well as linked to severe pathological events (preeclampsia and intrauterine growth restriction), and there is a need for reliable methods allowing non-invasive evaluation of placental blood flow. Uteroplacental vascularisation is complex, and animal models are essential for the technical development and safety assessment of these imaging tools for human clinical use; however, these techniques can also be applied in the veterinary context. This paper reviews how ultrasound-based imaging methods such as 2D and 3D Doppler can provide valuable insight for the exploration of placental blood flow both in humans and animals and how new approaches such as the use of ultrasound contrast agents or ultrafast Doppler may allow to discriminate between maternal (non-pulsatile) and foetal (pulsatile) blood flow in the placenta. Finally, functional magnetic resonance imaging could also be used to evaluate placental blood flow, as indicated by studies in animal models, but its safety in human pregnancy still requires to be confirmed.

Impact on obstetric outcome of third-trimester screening for small-for-gestational-age fetuses.

OBJECTIVES: To evaluate the performance of screening for small-for-gestational-age (SGA) fetuses by ultrasound biometry at 30-35 weeks' gestation, and to determine the impact of screening on obstetric and neonatal outcomes. METHODS: For this prospective cohort study, pregnant women were recruited from two French university maternity centers between 2003 and 2006. Performance measures of third-trimester biometry for the prediction of SGA, defined as estimated fetal weight < 10(th) centile, were analyzed. Obstetric outcomes and neonatal health status were compared, first, between SGA neonates diagnosed correctly at ultrasound examination (true positive (TP); n = 45) and SGA neonates that went undiagnosed (false negative (FN); n = 110) and, second, between non-SGA neonates identified as normal at ultrasound examination (true negative (TN); n = 1641) and non-SGA neonates diagnosed incorrectly as SGA (false positive (FP); n = 101). RESULTS: In the prediction of SGA, third-trimester ultrasound had a sensitivity of 29.0% (95% CI, 22.5-36.6%) and specificity of 94.2% (95% CI, 93.0-95.2%). Positive and negative predictive values were 30.8% (95% CI, 23.9-38.7%) and 93.7% (95% CI, 92.5-94.8%), respectively. One hundred and ten SGA neonates went undiagnosed at ultrasound. Compared to the TN neonates considered as of normal weight at ultrasound, planned preterm delivery (before 37 weeks) and elective Cesarean section for a fetal growth indication were 2.4 (P = 0.01) and 2.85 (P = 0.003) times more likely to occur, respectively, in the FP group of non-SGA neonates, diagnosed incorrectly as SGA during the antenatal period. There was no statistically significant difference in 5-min Apgar score < 7, cord blood pH at birth < 7.15 and need for neonatal resuscitation between the two subgroups (TN vs FP and TP vs FN). CONCLUSIONS: The performance of third-trimester ultrasound screening for SGA seems poor, as it misses the diagnosis of a large number of SGA neonates. The consequences of routine screening for SGA in a low-risk population may lead to unnecessary planned preterm deliveries and elective Cesarean sections in FP pregnancies, without improved neonatal outcome in the FN pregnancies.

Type 2 diabetes in pregnancy: Rates of fetal malformations and level of preconception care.

An observational study was performed to assess the prevalence of fetal malformations and the level of preconception care in women with Type 2 diabetes. Pregnant women with Type 2 diabetes who delivered between 2002 and 2010 were recruited to the study. The fetal malformation rate of patients with Type 2 diabetes was compared with the rate in a control group; the general population. The malformation rate was 3.2 (7.2-2.2%; p < 0.0001) greater in the diabetes group. In addition, only 4% of women with Type 2 diabetes had preconception care. Despite evidence of benefits in women receiving preconception care, patients with Type 2 diabetes do not attend for preconception counselling and the malformation rate is high.

Evaluation of utero-placental vascularization using contrast-enhanced ultrasound: Early first trimester maternal perfusion of the intervillous space is confirmed.

INTRODUCTION: The objective was to confirm and semiquantify the maternal perfusion of the intervillous space between 8 and 13 + 6 gestational weeks (GW). METHODS: We conducted a prospective, multicenter, and nonrandomized open study. Women undergoing voluntary termination of pregnancy at three different gestational ages (Group 8 GW: 8 to 8 + 6 GW, Group 11GW: 11 to 11 + 6 GW and Group 13GW: 13 to 13 + 6 GW) were included, with 14 subjects per group. Women presenting with a personal risk of preeclampsia and/or intrauterine growth restriction were excluded. Contrast-enhanced ultrasound (CEUS) was performed with an intravenous bolus administration of 2.4 mL of microbubbles. The region of interest (ROI) was the entire placenta. The perfusion curves and kinetic parameters, including wash-in perfusion index, peak enhancement and mean transit time, were calculated. RESULTS: Of the 42 women initially included, interpretable perfusion curves could be obtained for 33. Regardless of the gestational age, contrast was observed in the entire placenta. No significant difference in perfusion parameters was observed between groups. There was an association between signal intensity and both maternal heart frequency and placental location. Signal intensity was decreased when the heart frequency increased (p < 0.05) and when the placenta was in a nonanterior position (p > 0.005). DISCUSSION: We confirmed the presence of maternal perfusion of the intervillous space as early as 8 GW. No significant increase in perfusion parameters was observed between 8 and 13 + 6 GW. Our observations, in accordance with the previous experiment published by Roberts et al.1, strongly challenge the classic trophoblastic plug theory.

Characterization of the skin-to-bone mechanical interaction on porcine scalp: A combined experimental and computational approach.

Fasciae are soft tissues permitting a large but finite sliding between organs, but also between skin and its underlying elements. The contribution of fasciae has been seldomly reported in the literature, and is usually neglected or overly simplified within simulations. In the present contribution, we propose to use peeling tests in order to quantify the skin-to-bone interaction associated with a simple computational approach based on a geometrical modeling of the skin-to-bone interface. To this aim, a new experimental set up combined with a computational model to characterize the skin-to-bone interaction were proposed. The current work is devoted to the porcine scalp complex since it constitutes a common mechanical surrogate for the human scalp complex. The ad hoc computational approach and peeling set up were firstly evaluated on a validation material, before being used to characterize the skin-to-bone interaction within 6 porcine specimens harvested from the scalp. Our experimental setup allowed to measure the peeling response of porcine scalp, showing a three-regimes response including a plateau force. The computational approach satisfyingly reproduced the peeling response based uniquely on experimental-based parameters and on a discrete modeling of skin-to-bone interface. The presented methodology is a first attempt to propose a computationally efficient geometrically based model able to take into account the skin-to-bone interaction up to failure and corroborated by experimental data, and may be largely extended to the modeling of soft interactions between biological human tissues in the future.

A preliminary quantification of the clinical gesture during vacuum assisted delivery on a training dummy.

BACKGROUND: The vacuum assisted delivery represents, in France, the most used operative vaginal delivery technique. The purpose was to provide a preliminar quantification of the operator's hand kinematics while performing a vacuum assisted delivery. METHODS: A group of 21 participants composed of 12 trainees and 9 obstetricians were recorded performing a vacuum assisted delivery on a training dummy, the matching fetal presentation was a left occiput anterior position. FINDINGS: The mean movement was composed of a first phase corresponding to a descendant pull, followed by an ascendant finish of the gesture. No significative difference were found between the trainees and the obstetricians' mean gesture. INTERPRETATION: This is the first quantification of the clinical gesture associated with the vacuum assisted delivery.

[Systematic karyotyping before ICSI: A necessary procedure? Analysis of case studies in the Nancy University Hospital Fertility Centre]. / Le caryotype avant ICSI, une procédure à abandonner ? Étude de pratiques au centre d'AMP du CHRU de Nancy.

INTRODUCTION: A constitutional karyotype is often assayed for the couple before ICSI management. The objective of this study was to assess the prevalence of chromosomal abnormality in an infertile population, the impact on the care of couples and its cost. METHODS: A single-center retrospective study was carried out at the Fertility Center of the University Hospital of Nancy, including all infertile couples who underwent a karyotype analysis from June 2009 to December 2016. RESULTS: 1252 couples were included. 7.9% had at least one abnormal karyotype. A change in care affected 22% of these couples, i.e. 1.7% of the total population. 9% of couples with karyotype abnormality underwent PGD. In the male population, the percentage of abnormal spermograms is significantly higher in the group with karyotype abnormality compared to the control group (85.7% vs. 46.5%, P<0.001). DISCUSSION: The constitutional karyotype, due to its high economic and human cost, and limited interest, is a screening method for chromosomal abnormalities that has no place systematically before performing IVF. The future lies in the restriction of the indications for prescribing the karyotype as well as in the realization of PGS in targeted situations.

Analysis of suction-based gripping strategies in wildlife towards future evolutions of the obstetrical suction cup.

The design of obstetrical suction cups used for vacuum assisted delivery has not substantially evolved through history despite of its inherent limitations. The associated challenges concern both the decrease of risk of soft tissue damage and failure of instrumental delivery due to detachment of the cup. The present study firstly details some of the suction-based strategies that have been developed in wildlife in order to create and maintain an adhesive contact with potentially rough and uneven substratum in dry or wet environments. Such strategies have permitted the emergence of bioinspired suction-based devices in the fields of robotics or biomedical patches that are briefly reviewed. The objective is then to extend the observations of such suction-based strategies toward the development of innovative medical suction cups. We firstly conclude that the overall design, shape and materials of the suction cups could be largely improved. We also highlight that the addition of a patterned surface combined with a viscous fluid at the interface between the suction cup and scalp could significantly limit the detachment rate and the differential pressure required to exert a traction force. In the future, the development of a computational model including a detailed description of scalp properties should allow to experiment various designs of bioinspired suction cups.

New insights into human functional ultrasound imaging.

Ultrasound imaging is a vital tool for exploring in vivo the placental function which is essential to understand pathological phenomena such as preeclampsia or intrauterine growth restriction. As technology advances including ready availability of three-dimensional (3D) probes and novel software, new markers of placental function become possible. The objective of this review was to provide an overview of the new ultrasound markers of placental function with a focus on the potential clinical application of three-dimensional power Doppler (3DPD). A broad-free text literature search was undertaken based on human placental studies and sixty full-text studies were included in this review. Three-dimensional power Doppler is a promising technique to predict preeclampsia in the first trimester. However, the influence of external factors such as body mass index, parameter standardisation and machine settings still need to be addressed. Contrast-enhanced ultrasound is currently reserved for research, because the required injected contrast mediums are not currently approved for use in pregnancy, although the safety data is reassuring.

Assessment of placental perfusion using contrast-enhanced ultrasound: A longitudinal study in pregnant rabbit.

OBJECTIVES: The main aim of the study was to quantitatively characterize placental perfusion using contrast-enhanced ultrasound in a longitudinal study performed in pregnant rabbits. As a secondary objective, we qualitatively assessed the placental perfusion. METHODS: Three pregnant rabbits were used. Contrast-enhanced ultrasound was performed twice for each dam, either on embryo development (ED) day 14, 21 or 28 of pregnancy, under general anesthesia. Both qualitative and quantitative analyses were performed based on ultrasound assessment. RESULTS: Altogether, data from 29 fetuses were analyzed: 10 at ED-14; 12 at ED-21, and 7 at ED-28. Placental vascularization was mainly peripheral at the earliest gestational age and became gradually homogeneous within the whole placenta as pregnancy progressed. Intensity parameters and relative blood flows significantly increased with gestational age. The wash-in and wash-out rates were correlated and a significant increase in wash-in compared to in wash-out rates was observed with increased gestational age. CONCLUSION: Contrast-enhanced ultrasound is feasible in animal models and allows qualitative and quantitative analysis of placental vascularization during pregnancy.

[Retrospective validation of a model to predict the outcome of pregnancies of unknown location]. / Évaluation rétrospective d'un algorithme d'aide à la décision concernant les grossesses de localisation indéterminée.

OBJECTIVE: The prediction model M6 classifies pregnancy of unknown location (PUL) into a low-risk or a high-risk group in developing ectopic pregnancy (EP). The aim of this study was to validate the two-step M6 model's ability to classify PUL in French women. MATERIAL AND METHODS: All women with a diagnosis of PUL over a year were included in this single center retrospective study. Patients with a diagnosis of EP at the first consultation of with incomplete data were excluded. For each patient, the M6 model calculator was used to classified them into "high risk of EP" and "low risk of EP" group. The reference standard was the final diagnostic: failed PUL (FPUL), intrauterine pregnancy (IUP) of EP. The statistical measures of the test's performance were calculated. RESULTS: Over the period, 255 women's consulted for a PUL, 197 has been included in the study. Final diagnosis were: 94 FPUL (94/197; 47.7%), 74 IUP (74/197; 37.6%) et 29 EP (29/197; 14.7%). The first step of the M6 model classified 16 women in the FPUL group of which 15 (15/16; 93.7%) correctly. The second step of the M6 model classified 181 women: 90 (90/181; 49.7%) in the "high risk of EP" group of which 63 (63/90; 70%) were FPUL/IUP and 27 (27/90; 30%) were EP. 91 (91/181; 50.3%) was classified in the "low risk of EP" group of which 90 (90/91; 98.9%) were FPUL/IUP and 1 (1/91; 1.1%) were EP. EP were correctly classified with sensitivity of 96.4%, negative predictive value of 98.9%, specificity of 58.8% and positive predictive value of 30.0%. CONCLUSIONS: The prediction model of PUL M6 classified EP in "high risk of EP group" with a sensitivity of 96.4%. It classified 50.3% of PUL in a "low risk of EP" group with a negative predictive value of 98.9%.

Short-term very low-calorie diet in obese females improves the haemostatic balance through the reduction of leptin levels, PAI-1 concentrations and a diminished release of platelet and leukocyte-derived microparticles.

BACKGROUND: In obesity, metabolic stress and inflammation in injured tissues could favour enhanced shedding of procoagulant microparticles (MPs). At sites of endothelium injury, the swift recruitment of procoagulant leukocyte-derived MPs enables the initiation of blood coagulation and thrombus growth. OBJECTIVES: In obese females, we sought to evaluate the impact of a very low-calorie diet (VLCD) on procoagulant MP levels, fibrinolytic status, inflammation and endothelium damage. METHODS: Circulating biomarkers of vascular damage, fibrinolytic status, platelet activation and inflammation were measured before, 30 and 90 days after starting a short-term VLCD. MPs were measured by flow cytometry and capture assays. Their procoagulant potential was quantified using functional prothrombinase assays and their cellular origin were determined using flow cytometry (endothelium, platelet, leukocyte, lymphocyte and erythrocyte-derived MP) or capture assays. RESULTS: A total of 24 obese females (39 ± 10 years) with a mean body mass index of 35 ± 4 kg m(-2) were prospectively enroled. Procoagulant leukocyte-derived MPs were associated with the waist circumference at baseline (r=0.534; P=0.010) and at 90 days follow-up (r=0.487; P=0.021). At 90 days, weight reduction (-9.8%) was associated with a lowering of blood pressure, improvement of metabolic parameters and a significant reduction of plasminogen activator inhibitor-1 (PAI-1) (-38%), procoagulant platelet-derived MPs (-43%), leukocyte-derived MPs (-28%) and leptin (-32%) levels. CONCLUSION: In obese females, a short-term VLCD results in an overall improvement of the haemostatic balance characterized by the reduction of PAI-levels, diminished release of platelet and leukocyte-derived MPs and a reduction in leptin levels, an adipocyte-derived cytokine.

Semi-automated adjusted measurement of nuchal translucency: feasibility and reproducibility.

OBJECTIVE: The variability of nuchal translucency thickness (NT) measurements in the first trimester appears to be associated in part with caliper placement. Methods for obtaining semi-automated adjusted measurements (SAAMs) can provide several NT values (maximum, minimum, mean and median) automatically within a manually set frame in the zone of interest. This study sought to assess the feasibility and reproducibility of these SAAM-NTs. METHODS: Three readers, two experts and one less experienced, examined archive images of 160 patients and obtained SAAM-NTs from them, on two separate occasions. The intra- and interobserver reproducibility were assessed by calculating the intraclass correlation coefficients (ICCs) for maximum, mean and median SAAM-NTs, and Bland-Altman plots were constructed. RESULTS: SAAM-NTs were technically feasible for all 160 images. The range of ICCs for intraobserver reproducibility was 0.76-0.93 for mean SAAM-NT, 0.76-0.95 for median SAAM-NT and 0.74-0.95 for maximum SAAM-NT. Interobserver ICCs were 0.85, 0.85 and 0.84 for mean SAAM-NT, median SAAM-NT and maximum SAAM-NT, respectively. There were no significant differences for intra- and interobserver reproducibility of median, mean and maximum SAAM-NTs. CONCLUSIONS: SAAM-NT is feasible with a high level of intra- and interobserver reproducibility. This easy-to-use method has the potential to simplify screening during the first trimester. It should be evaluated further and compared with the manual measurement method.

[Retrospective comparison of effectiveness of balloon catheter versus dinoprostone for cervical ripening]. / Comparaison rétrospective de l'efficacité du ballonnet extra-amniotique à la dinoprostone dans la maturation cervicale.

OBJECTIVE: To compare the effectiveness and the safety of cervical ripening between two methods: the Cook double balloon catheter and the dinoprostone pessary (Propess 10mg). METHODS: We performed a retrospective comparative study in a French maternity. We analyzed 404 women with induction of labour after 37 gestational weeks, with singleton cephalic live fetus, unscarred uterus, unruptured membranes, and Bishop score<6. The primary endpoint was the time between the start of the ripening and the delivery. Secondary endpoints include effectiveness and safety outcomes of the methods. RESULTS: Compared to dinoprostone pessary, the balloon catheter was associated with a longer time to delivery (34.4±16.5 vs 25.5±15.3h; P<0.001). This difference is found in both primiparous and multiparous women. Balloon catheter is also associated with a smaller improvement of the Bishop score (2.5±2.1 vs 4.2±2.9 Bishop's points; P<0.001) and more failure to achieve delivery in 24h (32.3% vs 56.7%; P<0.001). There was no difference in mother and fetal safety. CONCLUSION: In this retrospective study, cervical ripening using balloon catheter seems to lengthen the induction of labour. No difference in safety outcomes with dinoprostone was found.

[Skills assessment for the practice of fetal ultrasound biometry: Prospective validation of the OSAUS METHOD score]. / Évaluation des compétences pour la pratique de la biométrie échographique fœtale : validation prospective du score OSAUS METHOD.

OBJECTIVES: To develop and validate a customized variant for fetal biometry of the generic OSAUS score (Objective Structured Assessment of Ultrasound Skills) METHODS: The 5-points OSAUS METHOD grid was elaborated by defining five target skills specific to fetal biometry for each thematic item of the generic score. The level of skills of 43 trainees was prospectively assessed during an ultrasound examination by using this grid. The results of the "novice" level group (experience<10 ultrasounds) were compared to those of the "intermediate" level group (experience≥10 ultrasounds) (I). The reached/non-reached skills ratio within the different items composing the score allowed the identification of priority areas of improvement (II). Previously published distribution and actual distribution of ratings according to the generic pass/fail score were compared (III). RESULTS: Median scores of "novices" (n=29) and "intermediates" (n=14) groups were statistically different, 1.87 (±0.75) and 3.31 (±0.83) (P=1.85-5), respectively and corresponded to the pre-existing experience (I). A lower ratio of reached skill allowed the identification of "documentation of the examination" item as a priority area of improvement for both groups (II). The relevance of the pass/fail score is consolidated, even if an overlap was observed between novices and intermediates groups (III). CONCLUSIONS: The relevancy and feasibility of using OSAUS scoring method for fetal biometry are supported. In addition, the possibility of comparisons with generic OSAUS remains.

Fetal biometry in ultrasound: A new approach to assess the long-term impact of simulation on learning patterns.

CONTEXT: Simulation-based education (SBE) has demonstrated its acceptability and effectiveness in improving ultrasound training. Because of the high cost of its implementation (investment in equipment and supervision), a pragmatic assessment of the transfer of skills learned in SBE to clinical practice and the identification of its optimal scheduling conditions have been requested to optimize its input. OBJECTIVES: To quantify the long-term impact of simulation-based education (SBE) on the adequate performance of ultrasound fetal biometry measurements (I). The secondary objective was to identify the temporal patterns that enhanced SBE input in learning (II). METHODS: Trainees were arbitrarily assigned to a 6-month course in obstetric ultrasound with or without an SBE workshop. In the SBE group, the workshop was implemented 'before' or at an 'early' or a 'late-stage' of the course. Those who did not receive SBE were the control group. The ultrasound skills of all trainees were prospectively collected, evaluated by calculating the delta between OSAUS (Objective Structured Assessment of Ultrasound Skills) scores before and after the course (I). Concomitantly, the accuracy of trainees' measurements was assessed throughout the course by verifying their correlation with the corresponding measurements by their supervisors. The percentage of trainees able to perform five consecutive sets of correct measurements in the control group and in each SBE subgroup were compared (II). RESULTS: The study included 61 trainees (39 SBE and 22 controls). Comparisons between groups showed no significant difference in the quantitative assessment of skill enhancement (difference in the pre- and post-internship OSAUS score: 1.09 ± 0.87 in the SBE group and 0.72 ± 0.98 in the control group) (I). Conversely, the predefined acceptable skill level was reached by a significantly higher proportion of trainees in the 'early' SBE subgroup (74%, compared with 30% in the control group, P<0.01)(II). CONCLUSIONS: The quantitative assessment does not support the existence of long-term benefits from SBE training, although the qualitative assessment confirmed SBE helped to raise the minimal level within a group when embedded in an 'early' stage of a practical course.

[Challenges of coronary catheterization after TAVR]. / Difficultés de cathétérisme coronaire après TAVI.

PURPOSE: Coronary catheterization after transcatheter aortic valve implantation (TAVR) may be challenging. The main objective of the study is to assess the feasibility of coronary catheterization and angioplasty according to each type of valve. PATIENTS AND METHOD: We retrospectively studied coronary angiography or percutaneous angioplasty procedures after TAVR in two different centers. The catheterization success of coronary artery was evaluated according to the quality of engagement in ostium and opacification of the artery. Other indicators were collected including catheters used, fluoroscopy and angiography times, DAP and the volume of the contrast agent. RESULTS: Among 1512 TAVR procedures, 33 patients were included. The Sapien 3® valve was implanted in 22 patients and the Evolut® in 11 patients (7 Evolut-R® and 4 Evolut Pro®). Coronary angiography with selective or partially selective catheterization has been successfully performed in all patients with a Sapien 3® valve. In the Evolut® group we identified 3 cases of non-selective catheterization for the right coronary and 1 case for the left coronary. Standard Judkins catheters seem to be the most suitable for both types of valve with very good efficiency. CONCLUSION: The results of our study is promising for the future of TAVR with a coronary catheterization success rate close to 100% with some difficulties for the Evolut® supra-annular valves. Special attention should be paid to the technique of implantation and orientation of cups in the aortic sinus.

Correlation between uteroplacental three-dimensional power Doppler indices and true uterine blood flow: evaluation in a pregnant sheep model.

OBJECTIVES: Three-dimensional (3D) Doppler quantification within the uteroplacental unit could be of great help in understanding and screening for pre-eclampsia and intrauterine growth restriction. Yet the correlation between 3D Doppler indices and true blood flow has not been confirmed in vivo. The aim of this study was to evaluate this correlation in a pregnant sheep model. METHODS: A blood flow quantitative sensor and a controllable vascular occlusion system were placed around the common uterine artery in seven sheep in late pregnancy, while all the other arterial supplies were ligated. Several occlusion levels were applied, from 0 to 100%, simultaneously with 3D Doppler acquisitions of several placentomes, using standardized settings. Each placentome was analyzed using VOCAL™ (Virtual Organ Computer-aided AnaLysis) software. The correlation between true blood flow and Doppler indices (vascularization index (VI), flow index (FI) and vascularization flow index (VFI)) was evaluated, together with measurement reproducibility. RESULTS: Forty-eight acquisitions were analyzed. All 3D Doppler indices were significantly correlated with true blood flow. Higher correlations were observed for VI and VFI (r = 0.81 (0.74-0.87), P < 0.0001 and r = 0.75 (0.67-0.82), P < 0.0001) compared with FI (r = 0.53 (0.38-0.64) P < 0.0001). Both intra- and interobserver reproducibility were high, with intraclass correlation coefficients of at least 0.799. CONCLUSION: This is the first in-vivo experimental study confirming a significant correlation between true blood perfusion and quantitative 3D Doppler indices measured within the uteroplacental unit. These results confirm the potential usefulness of 3D Doppler ultrasound for the assessment of placental vascular insufficiency both in clinical cases and in a research setting.