Role of 3-D ultrasound in clinical obstetric practice: evolution over 20 years

Biopathologic Characterization and Grade Assessment of Breast Cancer With 3-D Multiparametric Ultrasound Combining Shear Wave Elastography and Backscatter Tensor Imaging

OBJECTIVE

Despite recent improvements in medical imaging, the final diagnosis and biopathologic characterization of breast cancers currently still requires biopsies. Ultrasound is commonly used for clinical examination of breast masses. B-Mode and shear wave elastography (SWE) are already widely used to detect suspicious masses and differentiate benign lesions from cancers. But additional ultrasound modalities such as backscatter tensor imaging (BTI) could provide relevant biomarkers related to tissue organization. Here we describe a 3-D multiparametric ultrasound approach applied to breast carcinomas in the aims of (i) validating the ability of BTI to reveal the underlying organization of collagen fibers and (ii) assessing the complementarity of SWE and BTI to reveal biopathologic features of diagnostic interest.

METHODS

Three-dimensional SWE and BTI were performed ex vivo on 64 human breast carcinoma samples using a linear ultrasound probe moved by a set of motors. Here we describe a 3-D multiparametric representation of the breast masses and quantitative measurements combining B-mode, SWE and BTI.

RESULTS

Our results reveal for the first time that BTI can capture the orientation of the collagen fibers around tumors. BTI was found to be a relevant marker for assessing cancer stages, revealing a more tangent tissue orientation for in situ carcinomas than for invasive cancers. In invasive cases, the combination of BTI and SWE parameters allowed for classification of invasive tumors with respect to their grade with an accuracy of 95.7%.

CONCLUSION

Our results highlight the potential of 3-D multiparametric ultrasound imaging for biopathologic characterization of breast tumors.

Automatic measurements of fetal intracranial volume from 3D ultrasound scans

Three-dimensional fetal ultrasound is commonly used to study the volumetric development of brain structures. To date, only a limited number of automatic procedures for delineating the intracranial volume exist. Hence, intracranial volume measurements from three-dimensional ultrasound images are predominantly performed manually. Here, we present and validate an automated tool to extract the intracranial volume from three-dimensional fetal ultrasound scans. The procedure is based on the registration of a brain model to a subject brain. The intracranial volume of the subject is measured by applying the inverse of the final transformation to an intracranial mask of the brain model. The automatic measurements showed a high correlation with manual delineation of the same subjects at two gestational ages, namely, around 20 and 30 weeks (linear fitting R2(20 weeks) = 0.88, R2(30 weeks) = 0.77; Intraclass Correlation Coefficients: 20 weeks=0.94, 30 weeks = 0.84). Overall, the automatic intracranial volumes were larger than the manually delineated ones (84 ± 16 vs. 76 ± 15 cm3; and 274 ± 35 vs. 237 ± 28 cm3), probably due to differences in cerebellum delineation. Notably, the automated measurements reproduced both the non-linear pattern of fetal brain growth and the increased inter-subject variability for older fetuses. By contrast, there was some disagreement between the manual and automatic delineation concerning the size of sexual dimorphism differences. The method presented here provides a relatively efficient way to delineate volumes of fetal brain structures like the intracranial volume automatically. It can be used as a research tool to investigate these structures in large cohorts, which will ultimately aid in understanding fetal structural human brain development.

Tail movements by late-term fetal pitvipers resemble caudal luring: prenatal development of an ambush predatory behaviour

With the advent of powerful imaging instruments, the prenatal behaviour of vertebrates has been discovered to be far more complex than previously believed, especially concerning humans, other mammals and birds. Surprisingly, the fetal behaviour of squamate reptiles (lizards, snakes and amphisbaenians), a group of over 11 000 extant species, are largely understudied. Using ultrasonography, 18 late-term pregnant copperhead snakes (Agkistrodon contortrix) from a single population were inspected for fecundity (number of fetuses). Unexpectedly, during the ultrasound procedure that involved 97 fetuses, we observed sinusoidal tail movements in 11 individuals from eight different copperhead mothers. These movements were indistinguishable from caudal luring, a mimetic ambush predatory strategy which is exhibited by newborn copperheads and other snakes. Caudal luring is initiated shortly after birth and is employed to attract susceptible vertebrate prey. Using the same ultrasound equipment and methods, we tested for this behaviour in two species of rattlesnakes (genus Crotalus) not known to caudal lure and none of the late-term fetuses showed any type of tail movements. Prenatal movements in humans and other vertebrates are known to be important for musculoskeletal and sensorimotor development. The fetal behaviours we describe for copperheads, and possibly other snakes, may be similarly important and influence early survival and subsequent fitness.

On the Epistemic Status of Prenatal Ultrasound: Are Ultrasound Scans Photographic Pictures?

Medical imaging is predominantly a visual field. In this context, prenatal ultrasound images assume intense social, ethical, and psychological significance by virtue of the subject they represent: the fetus. This feature, along with the sophistication introduced by three-dimensional (3D) ultrasound imaging that allows improved visualization of the fetus, has contributed to the common impression that prenatal ultrasound scans are like photographs of the fetus. In this article we discuss the consistency of such a comparison. First, we investigate the epistemic role of both analogic and digital photographic images as visual information-providing representations holding a high degree of objectivity. Second, we examine the structure and process of production of ultrasound scans and argue that a comparison between two-dimensional (2D) ultrasound and photography is justified. This is in contrast to 3D ultrasound images that, due to the intensive mathematical processing involved in their production, present some structural issues that obfuscate their ontological and epistemic status.

Predicting fetal weight by three-dimensional limb volume ultrasound (AVol/TVol) and abdominal circumference

BACKGROUND

Fetal weight is an important parameter to ensure maternal and child safety. The purpose of this study was to use three-dimensional (3D) limb volume ultrasound combined with fetal abdominal circumference (AC) measurement to establish a model to predict fetal weight and evaluate its efficiency.

METHODS

A total of 211 participants with single pregnancy (28-42 weeks) were selected between September 2017 and December 2018 in the Beijing Obstetrics and Gynecology Hospital of Capital Medical University. The upper arm (AVol)/thigh volume (TVol) of fetuses was measured by the 3D limb volume technique. Fetal AC was measured by two-dimensional ultrasound. Nine cases were excluded due to incomplete information or the interval between examination and delivery >7 days. The enrolled 202 participants were divided into a model group (134 cases, 70%) and a verification group (68 cases, 30%) by mechanical sampling method. The linear relationship between limb volume and fetal weight was evaluated using Pearson Chi-squared test. The prediction model formula was established by multivariate regression with data from the model group. Accuracy of the model formula was evaluated with verification group data and compared with traditional formulas (Hadlock, Lee2009, and INTERGROWTH-21st) by paired t-test and residual analysis. Receiver operating characteristic curves were generated to predict macrosomia.

RESULTS

AC, AVol, and TVol were linearly related to fetal weight. Pearson correlation coefficient was 0.866, 0.862, and 0.910, respectively. The prediction model based on AVol/TVol and AC was established as follows: Y = -481.965 + 12.194TVol + 15.358AVol + 67.998AC, R2adj = 0.868. The scatter plot showed that when birth weight fluctuated by 5% (i.e., 95% to 105%), the difference between the predicted fetal weight by the model and the actual weight was small. A paired t-test showed that there was no significant difference between the predicted fetal weight and the actual birth weight (t = -1.015, P = 0.314). Moreover, the residual analysis showed that the model formula's prediction efficiency was better than the traditional formulas with a mean residual of 35,360.170. The combined model of AVol/TVol and AC was superior to the Lee2009 and INTERGROWTH-21st formulas in the diagnosis of macrosomia. Its predictive sensitivity and specificity were 87.5% and 91.7%, respectively.

CONCLUSION

Fetal weight prediction model established by semi-automatic 3D limb volume combined with AC is of high accuracy, sensitivity, and specificity. The prediction model formula shows higher predictive efficiency, especially for the diagnosis of macrosomia.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03002246; https://clinicaltrials.gov/ct2/show/NCT03002246?recrs=e&cond=fetal&draw=8&rank=67.

Assessing lateral uterine wall defects and residual myometrial thickness after cesarean section

OBJECTIVE

Lateral wall ruptures in women with a history of cesarean section are less common but more complicated than anterior wall ruptures. Residual myometrial thickness (RMT) is believed to be valuable for assessing the probability of ruptures. This study aimed to assess the utility of OmniView (a sonographic reslicing technique) in evaluating the lateral uterine wall after cesarean section and evaluate the relationship between lateral and anterior wall RMT using OmniView and sagittal two-dimensional ultrasound.

STUDY DESIGN

This cross-sectional study examined changes in both the anterior and lateral uterine wall in women with a history of cesarean section in the past 12-18 months. OmniView with volume contrast imaging with a 2-mm slice thickness was used to generate coronal planes, and the OmniView RMT (OV-RMT) was calculated as a percentage. Blinded to the OV-RMT results, sonographic multiplanar views were used to acquire the optimum sagittal plane for evaluating the RMT, and the sagittal RMT (S-RMT) was calculated as a percentage. The reproducibility of OV-RMT and S-RMT between two observers was tested using interclass correlation (ICC). The relationship between two variables was tested using Spearman's rank correlation.

RESULTS

In 208 recruited patients, the prevalence of lateral uterine wall defects was 79 %. The interobserver and intraobserver reproducibility of S-RMT and OV-RMT had ICC coefficients over 0.9 with a p-value <0.001. S-RMT and OV-RMT did not follow a normal distribution, and the medians were significantly different (55.5 and 85.7, respectively). Spearman's rank correlation between OV-RMT and S-RMT had a rho (ρ) value of 0.24 (p < 0.05). Passing-Bablok regression had an intercept of 47.95 and a slope of 0.65.

CONCLUSION

OmniView can be used to assess lateral uterine wall defects, and OV-RMT is a reproducible and reliable method for quantifying this assessment. The RMT on the coronal plane was independently more intact than that on the sagittal plane, which might account for the lower incidence of lateral ruptures. Further studies could reveal a critical OV-RMT value that is safe for a trial of labor.

3D evaluation of fetal brain structures: reference values and growth curves

Background: The development of the fetal central nervous system is one of the most important fields of research in perinatology. Since the early 1980s, 3 D ultrasound has become one of the major research tools in obstetrics and gynecology.Objective: The aim of this study was to reconstruct thalamus, cerebellum and Cortex volumes of fetal brain and generate, for these volumes, growth curves related to gestational age.Methods: We enrolled 344 pregnant women. Using "Tomographic Ultrasound Imaging" (TUI), in all cases we obtained a satisfying 3 D acquisition of fetal brain. We reconstructed offline thalamus, cerebellum and cortex volumes using "Virtual Organ Computer-Aided AnaLysis" (VOCAL) or 4 D View (GE Healthcare).Results: Among the 344 fetuses examined, we obtained 314 thalamus volumes, 252 cerebellum volumes and 261 cortex volumes and we constructed the reference growth curves.Conclusion: Our study confirms the reliability of cerebral volumes evaluation using 3 D technology and how these cerebral structures grow through gestation.

Feasibility of High-Resolution Computed Tomography Imaging for Obtaining Ear Impressions for Hearing Aid Fitting

OBJECTIVE

This study investigated the feasibility of obtaining ear impressions for hearing aids by using 3-dimensional high-resolution computed tomography (HRCT) images.

STUDY DESIGN

Case series.

SETTING

One referral tertiary center.

SUBJECTS AND METHODS

Hearing-impaired adults who were fitted with 1 or 2 behind-the-ear hearing aid(s) and had undergone temporal bone HRCT for various ear pathologies were enrolled in this study. Earmolds were fabricated from the impressions obtained using the conventional ear canal silicone injection technique and the HRCT reconstructed technique. Outer ear canal resonance frequencies and amplitude in open ears and those measured with silicon and HRCT reconstructed earmolds were determined through real-ear gain measurements, including real-ear unaided gain (REUG) and real-ear occluded gain (REOG), for comparison.

RESULTS

A total of 50 HRCT reconstructed earmolds were compared with 50 conventional silicon injection earmolds. The average value of open ear canal resonance amplitude (REUG) for each ear was 0.41 to 16.76 dB. No statistically significant difference in resonance amplitude (REOG) was observed between silicon and reconstructed earmolds (paired t test, P > .05). The mean insertion loss (REOG-REUG) at all frequencies also did not differ significantly between the two earmolds (paired t test, P > .05).

CONCLUSION

According to our real-ear measurements, acoustic characteristics of the HRCT reconstructed earmolds were compatible with those of the silicone injection earmolds. Despite concerns about increased cost and radiation exposure, the HRCT reconstructed technique is a clinically useful and applicable method and can reduce potential safety complications for difficult cases.

Phenotype to genotype characterization by array-comparative genomic hydridization (a-CGH) in case of fetal malformations: A systematic review

The aim of the current review is to report a-CGH abnormalities identified in fetuses with prenatally diagnosed fetal malformations in whom a normal karyotype was diagnosed with conventional cytogenetic analysis. A systematic electronic search of databases (PubMed/Medline, EMBASE/SCOPUS) has been conducted from inception to May, 2017. Bibliographic analysis has been performed according to PRISMA statement for review. The following keywords were used: 'array-CGH' and 'fetal malformations" and "prenatal diagnosis"; alternatively, "microarray", "oligonucleotide array", "molecular biology", "antenatal diagnostics", "fetal diagnostics", "congenital malformations" and "ultrasound" were used to capture both "a-CGH" and "prenatal". One-hundred and twelve fetuses with prenatally diagnosed fetal malformations with normal karyotyping and a-CGH abnormalities detected are described. Single or multiple microarray abnormalities diagnosed have been classified in relation to different organ/system affected. The most frequent a-CGH abnormalities were detected in cases of congenital heart diseases (CDHs), multiple malformations and central nervous system (CNS) malformations. Maternal or paternal carrier-state was seen in 19.64% (22/112), of cases while the number of reported de novo mutations accounted for 46.42% (52/112) of all CNVs microarray abnormalities. Array-comparative genomic hydridization (a-CGH) may become an integral and complemantary genetic testing when fetal malformations are detected prenatally in fetuses with normal cytogenetic karyotype. In addition, a-CGH enables the identification of CNVs and VOUS and improves the calculation of recurrent risk and the genetic counseling.

Assessment of Fetal Congenital Heart Diseases by 4-Dimensional Ultrasound Using Spatiotemporal Image Correlation: Pictorial Review

The aim of this pictorial review is to describe the technical advances achieved through the application of 4-dimensional (4D) ultrasound using spatiotemporal image correlation (STIC) over conventional 2-dimensional ultrasound in the prenatal detection of congenital heart disease (CHD). Spatiotemporal image correlation is a volume imaging technique that simplifies fetal heart studies while providing more diagnostic information than is typically available from traditional 2-dimensional studies. Four-dimensional software allows the study of cardiac anatomy and function during a single cardiac cycle and has greatly contributed to diagnostic enhancement of CHD. Color flow and power Doppler can be added to STIC in the study of vessel anatomy and to increase the detection of ventricular septal defects. Anatomical details of the fetus can be displayed in multiple images such as using computed tomography or magnetic resonance imaging. In addition, cardiac anatomy can be sectioned freely and reconstructed using different reformatting applications. Realistic views of the fetal heart, with particular emphasis on myocardium and endocardium cushion, can be reached using novel lightening techniques. Moreover, using 4D ultrasound, echolucent structures can be converted into solid voxels generating "digital casts" of the fetal heart that enhances the understanding of the great vessel relationships in the ventricular inflow and outflow tracts. Recently, sillhouette mode has shown to improve depth perception and resolution compared with conventional 3D power Doppler in the study of inflow and outflow tracts. Here, a gallery of prenatally detected CHD using 4D ultrasound with STIC and different applications is described.

Intra- and interobserver agreement for fetal cerebral measurements in 3D-ultrasonography

The aim of this study is to evaluate intra- and interobserver agreement for measurement of intracranial, cerebellar, and thalamic volume with the Virtual Organ Computer-aided AnaLysis (VOCAL) technique in three-dimensional ultrasound images, in comparison to two-dimensional measurements of these brain structures. Three-dimensional ultrasound images of the brains of 80 fetuses at 20-24 weeks' gestational age were obtained from YOUth, a Dutch prospective cohort study. Two observers performed offline measurement of the occipitofrontal diameter, intracranial volume, transcerebellar diameter, cerebellar volume, and thalamic width, area, and volume, independently. VOCAL was used for calculation of the volumes. The two-way random, single measures intraclass correlation coefficient (ICC) was used for analysis of agreement and Bland-Altman plots were configured. Intra- and interobserver agreement was almost perfect for occipitofrontal diameter (intra ICC 0.88, 95% CI 0.82-0.92; inter ICC 0.91, 95% CI 0.85-0.94), intracranial volume (intra ICC 0.96, 95% CI 0.91-0.98; inter ICC 0.97, 95% CI 0.96-0.98) and transcerebellar diameter (intra ICC 0.91, 95% CI 0.86-0.94; inter ICC 0.86, 95% CI 0.78-0.910). For cerebellar volume, the intraobserver agreement was almost perfect (0.85, 95% CI 0.76-0.90), whereas the interobserver agreement was substantial (0.75, 95% CI 0.44-0.88). Agreement was only moderate for thalamic measurements. Bland-Altman plots for the volume measurements are normally distributed with acceptable mean differences and 95% limits of agreement. The intra- and interobserver agreement of the measurement of intracranial and cerebellar volume with VOCAL was almost perfect. These measurements are therefore reliable, and can be used to investigate fetal brain development. Thalamic measurements are not reliable enough.

Fractional fetal thigh volume in the prediction of normal and abnormal fetal growth during the third trimester of pregnancy

Background

Currently, 2-dimensional ultrasound estimation of fetal size rather than fetal growth is used to define fetal growth restriction, but single estimates in late pregnancy lack sensitivity and may identify small for gestational age rather than growth restriction. Single or longitudinal measures of 3-dimensional fractional thigh volume may address this problem.

Objective

We sought to derive normal values for 3-dimensional fractional thigh volume in the third trimester, determine if fractional thigh volume is superior to 2-dimensional ultrasound biometry alone for detecting fetal growth restriction, and determine whether individualized growth assessment parameters have the potential to identify fetal growth restriction remote from term delivery.

Study Design

This was a longitudinal prospective cohort study of 115 unselected pregnancies in a tertiary referral unit (St Mary’s Hospital, Manchester, United Kingdom). Standard 2-dimensional ultrasound biometry measurements were obtained, along with fractional thigh volume measurements (based on 50% of the femoral diaphysis length). Measurements were used to calculate estimated fetal weight (Hadlock). Individualized growth assessment parameters and percentage deviations in longitudinally measured biometrics were determined using a Web-based system (iGAP; http://iGAP.research.bcm.edu). Small for gestational age was defined <10th and fetal growth restriction <3rd customized birthweight centile. Logistic regression was used to compare estimated fetal weight (Hadlock), estimated fetal weight (biparietal diameter–abdominal circumference–fractional thigh volume), fractional thigh volume, and abdominal circumference for the prediction of small for gestational age or fetal growth restriction at birth. Screening performance was assessed using area under the receiver operating characteristic curve.

Results

There was a better correlation between fractional thigh volume and estimated fetal weight ((biparietal diameter–abdominal circumference–fractional thigh volume) obtained at 34-36 weeks with birthweight than between 2-dimensional biometry measures such as abdominal circumference and estimated fetal weight (Hadlock). There was also a modest improvement in the detection of both small for gestational age and fetal growth restriction using fractional thigh volume–derived measures compared to standard 2-dimensional measurements (area under receiver operating characteristic curve, 0.86; 95% confidence interval, 0.79–0.94, and area under receiver operating characteristic curve, 0.92; 95% confidence interval, 0.85–0.99, respectively).

Conclusion

Fractional thigh volume measurements offer some improvement over 2-dimensional biometry for the detection of late-onset fetal growth restriction at 34-36 weeks.

Toward noninvasive monitoring of ongoing electrical activity of human uterus and fetal heart and brain

•

Evaluated a fetal-maternal scanner for monitoring electrical maternal and fetal organ activity.

•

The simulated scanner can monitor the uterine and fetal heart and brain activity online.

•

Biomagnetic monitors similar to this instrument should be useful in clinical neurophysiology.

Objective

To evaluate whether a full-coverage fetal-maternal scanner can noninvasively monitor ongoing electrophysiological activity of maternal and fetal organs.

Methods

A simulation study was carried out for a scanner with an array of magnetic field sensors placed all around the torso from the chest to the hip within a horizontal magnetic shielding enclosure. The magnetic fields from internal organs and an external noise source were computed for a pregnant woman with a 35-week old fetus. Signal processing methods were used to reject the external and internal interferences, to visualize uterine activity, and to detect activity of fetal heart and brain.

Results

External interference was reduced by a factor of 1000, sufficient for detecting signals from internal organs when combined with passive and active shielding. The scanner rejects internal interferences better than partial-coverage arrays. It can be used to estimate currents around the uterus. It clearly detects spontaneous activity from the fetal heart and brain without averaging and weaker evoked brain activity at all fetal head positions after averaging.

Conclusion

The simulated device will be able to monitor the ongoing activity of the fetal and maternal organs.

Significance

This type of scanner may become a novel tool in fetal medicine.

Intraexaminer and Interexaminer Variability in 3D Fetal Volume Measurements During the Second and Third Trimesters of Pregnancy

OBJECTIVES

To assess intraexaminer and interexaminer reliability of 3-dimensional fetal sonographic measurements.

METHODS

Three-dimensional fetal organ volumes (head, kidney, total thigh volume, and fractional thigh volume) were acquired during the second and third trimesters, with the addition of placental volume in the second trimester, by 2 different experienced, blinded sonographers. Fifty-eight fetuses were examined from 21 to 39 weeks' gestation. Intraexaminer and Interexaminer reliability was assessed with Bland-Altman plots, and their 95% limits of agreement and intraclass correlation coefficients.

RESULTS

The most significant interexaminer error was observed in the second-trimester kidney volume (95% limits of agreement, ± 110%), and the best agreement was for the third-trimester fractional thigh volume (95% limits of agreement, ± 25%) and second-trimester head volume (95% limits of agreement, -7%-25%). Second- and third-trimester intraclass correlation coefficient results were all greater than 0.75, apart from second-trimester kidney volume intraexaminer (0.374) and interexaminer (0.061) measurements, second-trimester placenta interexaminer measurements (0.390), and third-trimester kidney interexaminer measurements (0.647).

CONCLUSIONS

Three-dimensional fetal sonographic volumes of the head, kidney, total thigh, and placenta have limited reproducibility, and improvements in measurement techniques are needed before they can be used routinely to assess fetal growth. The 3-dimensional fractional thigh volume can be reliably obtained in the late third trimester.

Assessment of fetus during second trimester ultrasonography using HDlive software: What is its real application in the obstetrics clinical practice?

AIM

To show imaging results from application of four-dimensional (4D) ultrasound lightening technique (HDlive™) in clinical obstetrics practice.

METHODS

Normal and abnormal fetuses at second and third trimester of pregnancy undergoing routine scan with 4D HDlive™ (5DUS) in the rendering mode are described. Realistic features of fetal structures were provided by 5DUS in the rendering mode. Normal anatomy as well as pathology like cleft lip, hypoplastic face, micrognathia, low-set ears, corpus callosum, arthrogryposis, aortic arch, left congenital diaphragmatic hernia are highlighted in this study. Anatomical details of the fetuses were provided by 5DUS with higher quality imaging modality compared to those obtained using conventional 2D/3D ultrasound.

RESULTS

Realistic views of fetal anatomy details were displayed by means of 5DUS in the rendering mode, with high image quality obtained either in low-risk or in high-risk obstetrics population. Corpus callosum, esophagus, and aortic arch were obtained in normal fetuses. Cleft lip, cleft lip and palate, micrognathia, hypoplastic face, low-set ears, arthrogryposis, left congenital diaphragmatic hernia, exomphalos, and clitoris hypertrophy were clearly rendered by 5DUS application.

CONCLUSION

The use of 5DUS in the rendering mode, when clinical available, was diagnostic in a variety of congenital anomalies, aided understanding of the parents-to-be and improved prenatal counseling and perinatal management.

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.

Three-dimensional ultrasound of the fetus: how does it help?

Three-dimensional ultrasonography (3-D US) was introduced to the field of fetal imaging in the early 1990s. Since then several publications have described potential applications for the diagnosis of congenital malformations as well as organ volumetry. This article reviews basic principles of 3-D US as well as its clinical applicability to prenatal diagnosis of abnormalities involving the face, spine and skeletal system, as well as potential applications of 3-D US for fetal cardiovascular and neuroimaging. Limitations related to motion artifacts, acoustic shadowing and barriers to clinical implementation of 3-D US in clinical practice are addressed.

Three-dimensional ultrasonography by means of HDlive rendering in the first trimester of pregnancy: A pictorial review

Our objective was to describe early embryo/fetus anatomy and abnormalities provided by three and four-dimensional (3D/4D) ultrasound using HDlive rendering technology in the first trimester of pregnancy. Normal and pathologic embryonic and fetal volume data set with postprocessing using HDlive rendering mode. Virtual fetoscopic imaging of the normal and pathologic fetus even at early stage of development with increasing maternal-fetal bonding process. HDlive represents a novel and valuable lightening system for 3D/4D ultrasound application that may aid the prenatal interpretation of early congenital malformations although limitations and cautions are still needed for inclusion in obstetric clinical practice.

Deficiency of the myogenic factor MyoD causes a perinatally lethal fetal akinesia

Background

Lethal fetal akinesia deformation sequence (FADS) describes a clinically and genetically heterogeneous phenotype that includes fetal akinesia, intrauterine growth retardation, arthrogryposis and developmental anomalies. Affected babies die as a result of pulmonary hypoplasia. We aimed to identify the underlying genetic cause of this disorder in a family in which there were three affected individuals from two sibships.

Methods

Autosomal-recessive inheritance was suggested by a family history of consanguinity and by recurrence of the phenotype between the two sibships. We performed exome sequencing of the affected individuals and their unaffected mother, followed by autozygosity mapping and variant filtering to identify the causative gene.

Results

Five autozygous regions were identified, spanning 31.7 Mb of genomic sequence and including 211 genes. Using standard variant filtering criteria, we excluded all variants as being the likely pathogenic cause, apart from a single novel nonsense mutation, c.188C>A p.(Ser63*) (NM_002478.4), in MYOD1. This gene encodes an extensively studied transcription factor involved in muscle development, which has nonetheless not hitherto been associated with a hereditary human disease phenotype.

Conclusions

We provide the first description of a human phenotype that appears to result from MYOD1 mutation. The presentation with FADS is consistent with a large body of data demonstrating that in the mouse, MyoD is a major controller of precursor cell commitment to the myogenic differentiation programme.

Early Detection of Cleft Lip by Three-Dimensional Transvaginal Ultrasound in Niche Mode in a Fetus With Trisomy 18 Diagnosed by Celocentesis

Transabdominal ultrasound examination carried out at 11.3 weeks' gestation suggested the diagnosis of holoprosencephaly (HPE). Transvaginal three-dimensional (3D) scan performed using the niche-mode technique enabled diagnosis of HPE, hypotelorism, and cleft lip (CL). The fetus was diagnosed with trisomy 18 by means of transvaginal celocentesis at the time of pregnancy termination. Although prenatal diagnosis of orofacial cleft can be enhanced by 3D ultrasound, only a few cases have been detected early in pregnancy. Here, we report a first-trimester case in which 3D ultrasound in niche mode improved the antenatal diagnosis of CL. Early fetal karyotyping can be accomplished by celocentesis in these cases.