Search

OBJECTIVE To describe the sonographic appearance and position of the choroid plexus of the fourth ventricle (4V-CP) between 12 and 21 weeks' gestation in normal fetuses and in fetuses with Dandy-Walker malformation (DWM) or Blake's pouch cyst (BPC). METHODS The study population comprised 90 prospectively recruited normal singleton pregnancies and 41 pregnancies identified retrospectively from our institutional database that had a suspected posterior fossa anomaly at 12-13 weeks' gestation based on the ultrasound finding of abnormal hindbrain spaces. In all cases the final diagnosis was confirmed by prenatal and/or postnatal magnetic resonance imaging or postmortem examination. All pregnancies underwent a detailed ultrasound assessment, including a dedicated examination of the posterior fossa, at 12-13 weeks, 15-16 weeks and 20-21 weeks of gestation. Two-dimensional ultrasound images of the midsagittal and coronal views of the brain through the posterior fontanelle and three-dimensional volume datasets were obtained. Multiplanar orthogonal image correlation with volume contrast imaging was used as the reference visualization mode. Two independent operators, blinded to the fetal outcome, were asked to classify the 4V-CP as visible or not visible in both normal and abnormal cases, and to assess if the 4V-CP was positioned inside or outside the cyst in fetuses with DWM and BPC. RESULTS Of the 41 fetuses with apparently isolated cystic posterior fossa anomaly in the first trimester, eight were diagnosed with DWM, 29 were diagnosed with BPC and four were found to be normal in the second trimester. The position of the 4V-CP differed between DWM, BPC and normal cases in the first- and second-trimester ultrasound examinations. In particular, in normal fetuses, no cyst was present and, in the midsagittal and coronal planes of the posterior fossa, the 4V-CP appeared as an echogenic oval-shaped structure located inside the 4V apparently attached to the cerebellar vermis. In fetuses with DWM, the 4V-CP was not visible in the midsagittal view because it was displaced inferolaterally by the cyst. In contrast, in the coronal view of the posterior brain, the 4V-CP was visualized in all cases with DWM at 12-13 weeks, with a moderate decrease in the visualization rate at 15-16 weeks (87.5%) and at 20-21 weeks (75%). In the coronal view, the 4V-CP was classified as being outside the cyst in all DWM cases at 12-13 weeks and in 87.5% and 75% of cases at 15-16 and 20-21 weeks, respectively. In fetuses with BPC, the 4V-CP was visualized in all cases in both the midsagittal and coronal views at 12-13 weeks and in 100% and 96.6% of cases, respectively, at 15-16 weeks. In the coronal view, the 4V-CP was classified as being inside the cyst in 28 (96.6%), 27 (93.1%) and 25 (86.2%) cases at 12-13, 15-16 and 20-21 weeks, respectively. The medial segment of the 4V-CP was visualized near the inferior part of the vermis. CONCLUSIONS Our study shows that longitudinal ultrasound assessment of the 4V-CP and its temporal changes from 12 to 21 weeks is feasible. The 4V-CP is located inside the cyst, just below the vermis, in BPC and outside the cyst, inferolaterally displaced and distant from the vermian margin, in DWM, consistent with the pathogenesis of the two conditions. The position of the 4V-CP is a useful sonographic marker that can help differentiate between DWM and BPC as early as in the first trimester of pregnancy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

These practice guidelines follow the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation, bringing together groups and individuals throughout the world, with the goal of improving the ultrasound assessment of the fetal Central Nervous System (CNS) anatomy. In fact, this document provides further guidance for healthcare practitioners for the evaluation of the fetal CNS during the mid-trimester ultrasound scan with the aim to increase the ability in evaluating normal fetal anatomy. Therefore, it is not intended to establish a legal standard of care. This document is based on consensus among perinatal experts throughout the world, and serves as a guideline for use in clinical practice.

Objective To examine the incidence and type of chromosomal abnormalities in fetuses with first trimester ultrasound anomalies and a low-risk cfDNA test for common trisomies. Methods In 486 singleton pregnancies undergoing invasive testing after combined screening, a detailed first trimester ultrasound assessment was carried out and a maternal blood sample was sent for cfDNA analysis. Ultrasound and cfDNA data were analyzed in relation to fetal karyotype. Results Invasive testing demonstrated a chromosomal abnormality in 157 (32.3%) of 486 fetuses. In 348 cases with a low-risk cfDNA test for common trisomies, NT ≥ 3.5 mm and/or a major structural defect were observed in 92 (26.4%) fetuses. A chromosomal abnormality was found in 17 (18.5%; 95%CI 10.55-26.41) of these pregnancies, including 1 (1.1%) case of trisomy 21 and 16 (17.4%) fetuses with abnormalities different from common trisomies. The respective incidence in the 256 cases with a low-risk cfDNA test result and no ultrasound anomalies was 2.3% (95% CI 0.49-4.20; n = 6). Conclusions In fetuses with first trimester ultrasound anomalies and a low-risk cfDNA result for trisomy 21, 18 and 13, diagnostic testing should be offered with the main objective to detect chromosomal abnormalities beyond common trisomies.

Objectives: To examine the evolution of tetralogy of Fallot (TOF) and outlet ventricular septal defect (VSD) with anterior malalignment (am) from the initial diagnosis at early fetal echocardiography through the gestation and to evaluate the impact of the first-trimester scan on the outcome. Methods: We identified cases of TOF or outlet VSD with am diagnosed before 16 weeks’ gestation. For all cases, prenatal data and pregnancy outcomes were evaluated. In continuing pregnancies, the evolution in severity of the disease was assessed. Results: Fifty-one fetuses with TOF or outlet VSD with am were diagnosed at early fetal echocardiography. Parents opted for termination of pregnancy in all 23 cases associated with additional anomalies. In 2 of 28 continuing pregnancies, there was an intrauterine death. In the remaining 26, there was progression in severity in 7 (by 20–22 weeks in 3 cases and during the third trimester in the remaining 4). Conclusions: TOF and outlet VSD with am diagnosed before 16 weeks’ gestation can progress in severity throughout pregnancy in over one-quarter of cases. In addition, a high proportion of cases diagnosed in the first trimester may have associated extracardiac anomalies, with a significant impact on clinical management and on the rate of early termination of pregnancy.

Objective The aim of this study was to evaluate whether in fetuses with open spina bifida the tentorium is downward displaced and vertically oriented already at the 11-13 weeks scan and is reflected in an alteration of the Brainstem-Tentorium (BST) angle. Patients and methods Two groups of patients were recruited in three Fetal Medicine referral Centers: the prospectively collected control group included singleton pregnancies with a normal sonographic examination after first trimester combined screening for chromosomal abnormalities and normal outcome. The study group was selected retrospectively and enclosed all cases with open spina bifida. In all cases the position of the tentorium and the torcular Herophili (TH) were identified in the midsagittal view of the fetal brain at 11-13 weeks with the use of color Doppler; the BST angle was calculated in the same view. Results In the period 2015-2020 sixty normal fetuses were included in the control group; in these fetuses the BST angle was found to be independent of gestational age or crown rump length (p 0.8815, R2 0.0003861), with a mean value of 48.7 degrees and a standard deviation of 7.8 degrees. The study group included twenty-two fetuses with OSB, where the BST angle was close to 90 degrees (mean value: 88.1 degrees; standard deviation: 1.18 degrees). Comparison of BST angle measurements between the control group and cases of OSB showed a statistically significant difference (p =0.01531). Conclusion In all fetuses with OSB the BST angle is significantly larger than in normal controls with the tentorium being almost perpendicular to the BS. This sign confirms the inferior displacement of the tentorium cerebelli in respect of its normal insertion on the occipital clivus already in the first trimester of pregnancy and is useful in the diagnosis of Chiari II at this early stage. In all these fetuses the low position of the tentorium and TH is also easily visible, even subjectively. This article is protected by copyright. All rights reserved.

BACKGROUND AND AIM OF THE STUDY Scientific Societies do not recommend the use of cell-free DNA (cfDNA) testing as a first-tier screening for microdeletion and microduplication syndromes (MMs). The aim of this study was to review the current available literature on the performance of cell-free DNA as a screening for MMs. METHODS Medline, Embase and the Cochrane Library were searched electronically from 2000 to January 2020 and articles reporting the diagnostic performance of cfDNA screening for MMs in large (>5000 cases) series were included. Between-study heterogeneity and random effect model for screen positive rate (SPR), false positive rate (FPR) and positive predictive value (PPV) were calculated. RESULTS We identified 42 papers, seven included, for a total of 474,189 pregnancies and 210 cases of MMs. Diagnostic verification of positive cases was available overall in 486 (71.68 %) of 678 cases. The weighted pooled SPR, FPR and PPV were 0.19% (95% CI = 0.09-0.33), 0.07 (95% CI = 0.02-0.15) and 44.1 (95% CI = 31.49-63.07). In conclusion, the pooled PPV of cfDNA testing in screening for MMs was about 40%, ranging from 29% to 91%, for an overall FPR

Objective: The aim of this study was to report the rate of additional anomalies detected exclusively at prenatal magnetic resonance imaging (MRI) in fetuses with isolated severe ventriculomegaly undergoing neurosonography. Method: Multicenter, retrospective, cohort study involving 20 referral fetal medicine centers in Italy, United Kingdom, Spain and Denmark. Inclusion criteria were fetuses affected by isolated severe ventriculomegaly (≥15 mm), defined as ventriculomegaly with normal karyotype and no other additional central nervous system (CNS) and extra-CNS anomalies on ultrasound. In all cases, a multiplanar assessment of fetal brain as suggested by ISUOG guidelines on fetal neurosonography had been performed. The primary outcome was the rate of additional CNS anomalies detected exclusively at fetal MRI within two weeks from neurosonography. Subgroup analyses according to gestational age at MRI (

Introduction: The objective of the study was to provide more detailed data about fetal isolated upward rotation of the cerebellar vermis rotation (Blake’s pouch cyst) in particular regarding pregnancy outcome. Methods: This is a retrospective study of all cases of fetal isolated upward rotation of the cerebellar vermis (URCV) diagnosed in 3 referral centers in Italy from January 2009 to November 2019. Whenever possible, prenatal magnetic resonance imaging (MRI) was performed and a fetal karyotype was obtained. A detailed follow-up was obtained by consultation of medical records, interview with the parents, and the pediatricians. Results: Our study population included 111 patients with a prenatal diagnosis of isolated URCV made at a median gestational age of 21 weeks +3 days (interquartile range (IQR) 21 + 0–22 + 2). The median brain stem-vermis (BV) angle was 27° (IQR 24–29°). In 37.9% of the cases, a regression of the finding with restoration of normal anatomy was noted at a follow-up scan or at postnatal checks. A BV angle of 25° or less predicted regression with a probability in excess of 90%. MRI was performed in utero or at birth in 101 patients and always confirmed sonographic diagnosis. Fetal CGH array and/or karyotype was available in 97 cases and was always normal, but in 1 case. A postnatal follow-up was available in 102 infants (mean 7 months, range 0–10 years of age) and documented a normal neurologic development in all the cases. Conclusions: Isolated URCV is most likely a normal variant of fetal anatomy without clinical consequences, at least at an early follow-up. A BV angle of 25° or less predicts intrauterine regression of the finding, but the outcome is good in all the cases. When a confident sonographic diagnosis is made, MRI is not mandatory. The risk of a chromosomal anomaly in these cases is probably low.

mTOR dysregulation has been described in pathological conditions, such as cardiovascular and overgrowth disorders. Here we report on the first case of a patient with a complex congenital heart disease and an interstitial duplication in the short arm of chromosome 1, encompassing part of the mTOR gene. Our results suggest that an intragenic mTOR microduplication might play a role in the pathogenesis of non-syndromic congenital heart defects (CHDs) due to an upregulation of mTOR/Rictor and consequently an increased phosphorylation of PI3K/AKT and MEK/ERK signaling pathways in patient-derived amniocytes. This is the first report which shows a causative role of intragenic mTOR microduplication in the etiology of an isolated complex CHD.

Objectives: To assess the role of fetal magnetic resonance imaging (MRI) in detecting associated anomalies in fetuses presenting with mild or moderate isolated ventriculomegaly (VM) undergoing multiplanar ultrasound evaluation of the fetal brain. Methods: This was a multicenter, retrospective, cohort study involving 15 referral fetal medicine centers in Italy, the UK and Spain. Inclusion criteria were fetuses affected by isolated mild (ventricular atrial diameter, 10.0–11.9 mm) or moderate (ventricular atrial diameter, 12.0–14.9 mm) VM on ultrasound, defined as VM with normal karyotype and no other additional central nervous system (CNS) or extra-CNS anomalies on ultrasound, undergoing detailed assessment of the fetal brain using a multiplanar approach as suggested by the International Society of Ultrasound in Obstetrics and Gynecology guidelines for the fetal neurosonogram, followed by fetal MRI. The primary outcome of the study was to report the incidence of additional CNS anomalies detected exclusively on prenatal MRI and missed on ultrasound, while the secondary aim was to estimate the incidence of additional anomalies detected exclusively after birth and missed on prenatal imaging (ultrasound and MRI). Subgroup analysis according to gestational age at MRI (< 24 vs ≥ 24 weeks), laterality of VM (unilateral vs bilateral) and severity of dilatation (mild vs moderate VM) were also performed. Results: Five hundred and fifty-six fetuses with a prenatal diagnosis of isolated mild or moderate VM on ultrasound were included in the analysis. Additional structural anomalies were detected on prenatal MRI and missed on ultrasound in 5.4% (95% CI, 3.8–7.6%) of cases. When considering the type of anomaly, supratentorial intracranial hemorrhage was detected on MRI in 26.7% of fetuses, while polymicrogyria and lissencephaly were detected in 20.0% and 13.3% of cases, respectively. Hypoplasia of the corpus callosum was detected on MRI in 6.7% of cases, while dysgenesis was detected in 3.3%. Fetuses with an associated anomaly detected only on MRI were more likely to have moderate than mild VM (60.0% vs 17.7%; P < 0.001), while there was no significant difference in the proportion of cases with bilateral VM between the two groups (P = 0.2). Logistic regression analysis showed that lower maternal body mass index (adjusted odds ratio (aOR), 0.85 (95% CI, 0.7–0.99); P = 0.030), the presence of moderate VM (aOR, 5.8 (95% CI, 2.6–13.4); P < 0.001) and gestational age at MRI ≥ 24 weeks (aOR, 4.1 (95% CI, 1.1–15.3); P = 0.038) were associated independently with the probability of detecting an associated anomaly on MRI. Associated anomalies were detected exclusively at birth and missed on prenatal imaging in 3.8% of cases. Conclusions: The incidence of an associated fetal anomaly missed on ultrasound and detected only on fetal MRI in fetuses with isolated mild or moderate VM undergoing neurosonography is lower than that reported previously. The large majority of these anomalies are difficult to detect on ultrasound. The findings from this study support the practice of MRI assessment in every fetus with a prenatal diagnosis of VM, although parents can be reassured of the low risk of an associated anomaly when VM is isolated on neurosonography. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Objective: To estimate the procedure-related risk of miscarriage in pregnancies undergoing amniocentesis (AC) following inconclusive results for a chorionic villus sampling (CVS). Methods: This was a multicentric retrospective cohort study of patients in which both CVS at 11–13 weeks’ gestation and AC at 16–22 weeks were performed between January 1st, 2008, and July 31st, 2017. The primary outcome measure was pregnancy loss prior to 24 weeks gestation; the secondary one was intrauterine demise after 24 weeks. Results: A total of 287 patients underwent transabdominal CVS and AC. Nine patients were lost at follow-up; therefore, the analysis was conducted on a population of 278 patients (275 singletons and 3 dichorionic twin pregnancies). AC was performed because of placental mosaicism (93.6%), failure of direct/semidirect preparation of trophoblastic cells (3.2%), or targeted genetic testing after the diagnosis of an anomaly in the second trimester (3.2%). In continuing pregnancies, there were no fetal losses prior to 24 weeks’ gestation. Two intrauterine demises (including 1 fetus with multiple anomalies and growth restriction) in the third trimester were recorded. Conclusion: Patients undergoing midtrimester AC because of an inconclusive result of CVS can be reasonably reassured that in general the risk of miscarriage and fetal loss following the procedure is very small.

Objectives To introduce a new sonographic marker of intrathoracic liver herniation in fetuses with left-sided congenital diaphragmatic hernia (CDH). Methods In a consecutive series of fetuses with isolated CDH, an ultrasound volume of the fetal abdomen was acquired. On this volume, offline calculation of the angle formed by the midline of the abdomen (joining the center of the vertebral body to the abdominal insertion of the umbilical cord) and a second line joining the center of the vertebral body to the intra-abdominal convexity of the umbilical vein was carried out to give the umbilical vein deviation angle (UVDA). The UVDA was measured in a group of normal fetuses selected as controls. At follow-up, the presence of liver herniation was investigated in all cases of CDH. UVDA values were compared between the CDH group and controls, and between CDH ‘liver-up’ vs ‘liver-down’ cases. A receiver–operating characteristics (ROC) curve was constructed to identify a cut-off value of the UVDA with the highest accuracy in predicting liver herniation in the CDH group. Results Between 2009 and 2015, 22 cases of left-sided CDH were included in the study group, of which nine cases had liver herniation. Eighty-eight normal fetuses were recruited as controls. The UVDA was significantly higher in the cases vs controls (15.25 ± 7.91° vs 7.68 ± 1.55°; P

Objective The aim of the study was to evaluate the feasibility of obtaining the three-vessel and trachea view (3VTV) in an unselected population undergoing first trimester screening for aneuploidy, and to investigate its role in the early detection of congenital heart defects (CHD). Methods Cardiac examination was performed by expert sonographers. Abnormal findings of 3VTV were classified in three different subgroups: number, size and spatial relationship of the vessels. Results We enrolled 6350 consecutive singleton pregnancies and included 5343 cases. Examination of 3VTV was feasible in 94% of cases. Fifty-seven (1%) CHD were present in the study period; 24 cases were excluded because parents opted for termination of pregnancy. Of the remaining 33 cases, 25 were suspected at the first trimester and eight were detected only at the mid-trimester. An abnormal 3VTV was suspected in 22 cases, and it was confirmed in 21. Five cases that were erroneously classified in the subgroup of abnormal vessel number were actually characterized by a diminutive size of one of the great arteries. The detection rate for CHD, including 4-CV and 3VTV, was 75.8%. Conclusions Our study demonstrates that 3VTV is an easy plane to obtain by expert sonographers in an unselected population during first trimester. Typical suspicions include detection of abnormal number, size or spatial relationship of the vessels. © 2017 John Wiley & Sons, Ltd.

The role of the first-trimester scan has expanded from aneuploidy screening to the diagnosis of fetal malformations. Abnormal appearance of the posterior brain at 11-14 weeks gestation is a marker of cerebral anomalies; in fact an increased amount of fluid, particularly when the choroid plexus of the fourth ventricle is not visible and only 2 brain spaces instead of 3 are seen, may indicate the presence of cystic or cyst-like posterior fossa anomalies, such as Blake's pouch cyst or Dandy-Walker malformation.The purpose of this study was to assess the role of ultrasound scanning in the identification of cystic posterior fossa anomalies at 11-14 weeks gestation.A prospective cohort study of fetuses with cystic appearance of the posterior fossa at 11-14 weeks gestation was performed. In all cases and in a control group of 40 normal fetuses, the brainstem-tentorium angle was also measured. The presence or absence of cystic posterior anomalies was determined at birth or at postmortem evaluation.In the period 2014-2018, 32 fetuses with an increased brainstem-occipital bone distance and/or failure to visualize the choroid plexus of fourth ventricle (2 brain spaces) were seen. Of these, 18 fetuses were terminated in the first trimester because of associated anomalies and were excluded from the study because of unavailable autoptic findings. The remaining 14 fetuses eventually were found to have a Dandy-Walker malformation in 4 cases, a Blake's pouch cyst in 8 cases, and normal brain anatomy in 2 cases. Two brain spaces were seen in all cases with Dandy-Walker malformation and in 2 of 8 cases with Blake's pouch cyst. Both brainstem-occipital bone measurement and brainstem-tentorium angle were significantly different in fetuses with Dandy-Walker malformation, Blake's pouch cyst, and control subjects (P.0001). The brainstem-occipital bone z-scores of fetuses with Dandy-Walker malformation and Blake's pouch cyst were always +3 or more and +1.7 or more, respectively. The brainstem-tentorium angle z-scores were always -5 or less and -0.1 or less, respectively.Our study confirms that sonography of the posterior brain at 11-14 weeks gestation allows the identification of cystic posterior fossa anomalies. A large brainstem-occipital bone predicts Dandy-Walker malformation or Blake's pouch cyst. The presence of 2 brain spaces and a small brainstem-tentorium angle are correlated significantly with the presence of Dandy-Walker malformation.

Introduction: Neonates with D-transposition of the great arteries (dTGA) may die at birth because of the inadequate intracardiac mixing due to a misdiagnosed restrictive foramen ovale. We reviewed our experience in echocardiographic assessment and perinatal management of fetuses with dTGA searching for new features that may predict the need for urgent balloon atrial septostomy (BAS) immediately after birth. Patients and Methods: We included fetuses diagnosed with dTGA between January 2000 and December 2014. We assessed pre- and postnatal appearance of the foramen ovale, ductus arteriosus and pulmonary veins. Both the diagnostic findings at the time of last prenatal echocardiogram and those findings deriving from a retrospective reevaluation of stored videos were considered. BAS was defined as urgent if performed in neonates with restrictive foramen ovale and severe hypoxemia. Results: We reviewed 40 fetuses with dTGA. 20/40 fetuses received urgent BAS at birth. Not only the restrictive but also the hypermobile and the redundant appearance of the foramen ovale was significantly associated with urgent BAS (p < 0.0001, p = 0.002 and p = 0.0001, respectively). Conclusions: Prenatal evaluation of the foramen ovale appearance in fetuses with dTGA is still challenging. Based on our experience, also the redundant foramen ovale appearance may need urgent BAS at birth.

Objective To assess the risk of 22q11.2 deletion in fetuses with a prenatal diagnosis of right aortic arch without intracardiac anomalies (RAA-no ICA). Methods This was a retrospective study of all fetuses with RAA-no ICA diagnosed prenatally at three referral centers, between 2004 and 2014. A detailed sonographic examination was performed in each case, including visualization of the thymus and of the head and neck vessels to identify the presence of an aberrant left subclavian artery (ALSA). Karyotyping and fluorescence in situ hybridization analysis for diagnosis of 22q11.2 deletion were always offered either prenatally or postnatally. Clinical and echocardiographic examinations were performed in livebirths and a postmortem examination in cases of termination of pregnancy. Results During the study period, 85 fetuses were diagnosed prenatally with RAA-no ICA. Genetic or clinical data were not available for three cases and these were excluded from analysis. 22q11.2 deletion was found in 7/82 cases (8.5% (95% CI, 3.8–17.3%)). The thymus was small or non-visualized in all seven cases and additional abnormal sonographic findings were present in four. Conclusion 22q11.2 deletion is present in a clinically significant proportion of fetuses with a prenatal diagnosis of RAA-no ICA. In such cases, a detailed sonographic examination, with assessment of the thymus in particular, may be useful to further define the level of risk for 22q11.2 deletion. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Objective To describe the sonographic appearance of fetal posterior fossa anatomy at 11–14 weeks of pregnancy and to assess the outcome of fetuses with increased intracranial translucency (IT) and/or brainstem-to-occipital bone (BSOB) diameter. Methods Reference ranges for brainstem (BS), IT and cisterna magna (CM) measurements, BSOB diameter and the BS : BSOB ratio were obtained from the first-trimester ultrasound examination of 233 fetuses with normal postnatal outcome (control group). The intraobserver and interobserver variability of measurements were investigated using 73 stored ultrasound images. In addition, a study group of 17 fetuses with increased IT and/or BSOB diameter was selected to assess outcome. Results No significant intraobserver or interobserver variability was found for any measurement in the control group. In the study group, IT was increased in all cases and BSOB diameter was above the 95th centile of the calculated normal range in all but two (88%) cases. In 13/17 study cases, only two of the three posterior brain spaces were recognized on ultrasound. These 13 fetuses had a larger BSOB diameter than did the four cases that showed all three posterior brain spaces, and had severe associated anomalies including Dandy–Walker malformation (DWM) and/or chromosomal anomalies. Conclusions Visualization of the fetal posterior fossa anatomy at 11–14 weeks' gestation is feasible. Increased fluid in the posterior brain at 11–14 weeks, particularly in the case of non-visibility of the septation that divides the future fourth ventricle from the CM, is an important risk factor for cystic posterior fossa malformations, in particular DWM, and/or chromosomal aberrations. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Objective The objective of this study was to investigate a strategy for clinical implementation of cell-free DNA (cfDNA) testing in high-risk pregnancies after first-trimester combined screening. Methods In 259 singleton pregnancies undergoing invasive testing after first-trimester combined screening, a maternal blood sample was sent to the laboratory Natera for cfDNA testing using a single-nucleotide polymorphism-based methodology. Results The cfDNA test provided a result in 249 (96.1%) pregnancies and, among these, identified as being at high risk 35 of 36 cases of trisomy 21, 13 of 13 with trisomy 18, five of five with trisomy 13 and three of four with sex chromosome aneuploidies. A policy of performing an invasive test in women with a combined risk of ≥1 in 10 or NT ≥4 mm and offering cfDNA testing to the remaining cases would detect all cases of trisomy 21, 18 or 13, 80% of sex aneuploidies and 62.5% of other defects and would avoid an invasive procedure in 82.4% of euploid fetuses. Conclusion In high-risk pregnancies after combined screening, a policy of selecting a subgroup for invasive testing and another for cfDNA testing would substantially reduce the number of invasive procedures and retain the ability to diagnose most of the observed aneuploidies. © 2016 John Wiley & Sons, Ltd.

Anomalies of the corpus callosum (ACC) and septum pellucidum are disorders of prosencephalic midline development, which are often associated with other brain abnormalities or may be part of a syndrome. Diagnosis of ACC is usually impossible before 18 to 20 weeks' gestation because the formation of the corpus callosum is incomplete. ACC can be complete or partial. The main indirect US signs of complete ACC include colpocephaly, absent CSP, and increased separation of the hemispheres. The definitive diagnosis relies on the demonstration of the absence of the corpus callosum on midsagittal and coronal views of the fetal brain. Partial ACC could be difficult to identify as in 1/3 of the cases there are no indirect signs. Fetal magnetic resonance imaging (MRI) is more sensitive than US in the recognition of possible associated cerebral anomalies. The overall prognosis of ACC is controversial and may range from asymptomatic with normal intellectual capacities to severe mental retardation. Several studies have reported a worse prognosis in the presence of additional anomalies. Cases of isolated ACC seem to have a better prognosis. Absence of the septum pellucidum can be diagnosed by US in the second trimester of pregnancy. Some associated brain abnormalities are not detectable before the third trimester, and in most cases it is impossible to determine the presence of SOD before birth. MRI can visualize the size of the optic nerves and chiasma (in late pregnancy) to search for optic nerve or chiasma hypoplasia (SOD) and to show possible associated cortical abnormalities (SOD-plus). Clinical severity of ASP varies, and only 30% of patients manifest the complete clinical triad. Children with isolated ASP have a favorable neurological outcome, but 18% of fetuses diagnosed with ASP are at risk for SOD.