Lateral ventricles in fetuses with aneuploidies at 11-13 weeks' gestation

First-trimester ultrasound of the cerebral lateral ventricles in fetuses with open spina bifida: a retrospective cohort study

BACKGROUND

Beyond 18 weeks of gestation, an increased size of the fetal lateral ventricles is reported in most fetuses with open spina bifida. In the first trimester of pregnancy, the definition of ventriculomegaly is based on the ratio of the size of the choroid plexus to the size of the ventricular space or the entire fetal head. However, contrary to what is observed from the midtrimester of pregnancy, in most fetuses with open spina bifida at 11 to 13 weeks of gestation, the amount of fluid in the ventricular system seems to be reduced rather than increased.

OBJECTIVE

This study aimed to compare the biometry of the lateral ventricles at 11 0/7 to 13 6/7 weeks of gestation between normal fetuses and those with confirmed open spina bifida.

STUDY DESIGN

This was a retrospective cohort study that included all cases of isolated open spina bifida detected at 11 0/7 to 13 6/7 weeks of gestation over a period of 5 years and a group of structurally normal fetuses attending at our center over a period of 1 year for the aneuploidy screening as controls. Transventricular axial views of the fetal brain obtained from cases and controls were extracted from the archive for post hoc measurement of cerebral ventricles. The choroid plexus-to-lateral ventricle length ratio, sum of the choroid plexus-to-lateral ventricle area ratio, choroid plexus area-to-fetal head area ratio, and mean choroid plexus length-to-occipitofrontal diameter ratio were calculated for both groups. The measurements obtained from the 2 groups were compared, and the association between each parameter and open spina bifida was investigated.

RESULTS

A total of 10 fetuses with open spina bifida were compared with 358 controls. Compared with controls, fetuses with open spina bifida showed a significantly smaller size of the cerebral ventricle measurements, as expressed by larger values of choroid plexus-to-lateral ventricle area ratio (0.49 vs 0.72, respectively; P<.001), choroid plexus-to-lateral ventricle length ratio (0.70 vs 0.79, respectively; P<.001), choroid plexus area-to-fetal head area ratio (0.28 vs 0.33, respectively; P=.006), and choroid plexus length-to-occipitofrontal diameter ratio (0.52 vs 0.60, respectively; P<.001). The choroid plexus-to-lateral ventricle area ratio was found to be the most accurate predictor of open spina bifida, with an area under the curve of 0.88, a sensitivity of 90%, and a specificity of 82%.

CONCLUSION

At 11 0/7 to 13 6/7 weeks of gestation, open spina bifida is consistently associated with a reduced amount of fluid in the lateral cerebral ventricles of the fetus, as expressed by a significantly increased choroid plexus-to-lateral ventricle length ratio, choroid plexus-to-lateral ventricle area ratio, choroid plexus area-to-fetal head area ratio, and choroid plexus length-to-occipitofrontal diameter ratio.

Development of the prosencephalic structures, ganglionic eminence, basal ganglia and thalamus at 11 + 3 to 13 + 6 gestational weeks on 3D transvaginal ultrasound including normative data

OBJECTIVES

To show the development of ganglionic eminence, basal ganglia and thalamus/hypothalamus in week 11 + 3 to 13 + 6 by transvaginal 3D ultrasound.

METHODS

To visualize the prosencephalic structures surrounding the 3rd ventricle, 285 three-dimensional ultrasound volume blocks from 402 fetuses examined were selected in a prospective transvaginal 3D study to compare ultrasound images of ganglionic eminence, basal ganglia, thalamus/hypothalamus with embryological sections. In addition, measurements of the described structures were made in 104 fetuses to quantify the embryological development.

RESULTS

The sonomorphologic characteristics of ganglionic eminence, basal ganglia and thalamus/hypothalamus are described in 71% of the fetuses examined. Measurements of the structures in 57% of the fetuses, show the following results: axGE ap = 0.17 + 0.112*CRL; axGE/I = 0.888 + 0.048*CRL; axGE/BG = 0.569 + 0.041*CRL; coGE/BG = 0.381 + 0.048*CRL; coTh lat = - 0.002 + 0.135*CRL; coTh/HyT = 3.68 + 0.059*CRL; co3.V lat = 0.54 + 0.008*CRL.

CONCLUSION

Transvaginal 3D neurosonography allows visualization and measurement of normal structures in the fetal prosencephalon at 11 + 3 to 13 + 6 weeks of gestation (GW) including details of ganglionic eminence (GE), basal ganglia (BG), and thalamus/hypothalamus (Th/HyT). Further scientific work is needed before using the results to decide on pathological changes in patients.

First-trimester choroid-plexus-to-lateral-ventricle disproportion and prediction of subsequent ventriculomegaly

OBJECTIVE

Ventriculomegaly can be associated with long-term neurodevelopmental impairment. Prenatal diagnosis of ventriculomegaly is most commonly made at the routine second-trimester anomaly scan. The value of first-trimester ultrasound has expanded to early diagnosis and screening of fetal abnormalities. The objective of this study was to assess the predictive accuracy of first-trimester choroid-plexus-to-lateral-ventricle-or-head ratios for development of ventriculomegaly at a later gestational age.

METHODS

This was a case-control study of fetuses with isolated ventriculomegaly diagnosed after 16 weeks' gestation and a control group of normal fetuses (without ventriculomegaly). The exclusion criteria included aneuploidy, genetic syndrome and/or other brain abnormality. Stored two-dimensional first-trimester ultrasound images were analyzed blindly offline and fetal biometry was performed in the axial view of the fetal head. The ratios of choroid plexus area (PA) to lateral ventricular area (VA), choroid plexus length (PL) to lateral ventricular length (VL), choroid plexus diameter (PD) to lateral ventricular diameter (VD) and PA to biparietal diameter (BPD) were measured at 11 + 0 to 13 + 6 weeks' gestation. Intra- and interobserver variability of measurement of these fetal head biometric parameters at 11 + 0 to 13 + 6 weeks' gestation were assessed in 20 normal fetuses using intraclass correlation coefficients with 95% CI. The accuracy of first-trimester biometric measurements for prediction of ventriculomegaly was assessed using the area under the receiver-operating-characteristics curves (AUC).

RESULTS

The analysis included 683 singleton pregnancies, of which 102 fetuses were diagnosed with ventriculomegaly. Ventriculomegaly was mild in 86 (84.3%) cases and severe in the other 16 (15.7%). All first-trimester fetal choroid-plexus-to-lateral-ventricle/head ratios were significantly lower in cases with ventriculomegaly compared with controls (P < 0.001), with good inter- and intraobserver agreement (≥ 0.95) for the majority of the fetal head biometric parameters assessed. On adjusting for crown-rump length, optimism-adjusted AUC values obtained after cross-validation showed that both PL/VL ratio (AUC, 0.87 (95% CI, 0.73-0.98)) and PA/VA ratio (AUC, 0.90 (95% CI, 0.82-0.98)) had good predictive accuracy for severe ventriculomegaly. The PA/BPD ratio (AUC, 0.73 (95% CI, 0.54-0.90)) had modest predictive ability, which was significantly lower compared with that of the PA/VA ratio and PL/VL ratio (P = 0.003 and P = 0.001, respectively). The predictive accuracy of PD/VD ratio was low with an AUC of 0.65 (95% CI, 0.47-0.84). Optimism-adjusted AUC values obtained after cross-validation showed that PA/VA ratio offered the highest predictive accuracy for mild ventriculomegaly with an AUC of 0.84 (95% CI, 0.79-0.89), followed by PL/VL ratio (AUC, 0.82 (95% CI, 0.76-0.88)), PA/BPD ratio (AUC, 0.76 (95% CI, 0.69-0.82)) and PD/VD ratio (AUC, 0.75 (95% CI, 0.67-0.81)). Calibration plots showed that both PA/VA and PL/VL ratios had good calibration.

CONCLUSION

First-trimester prediction of ventriculomegaly using ratios of fetal choroid plexus to lateral ventricle/head appears promising. Future prospective studies are needed to validate the predictive accuracy of these ultrasound markers as a screening tool for ventriculomegaly. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

First Trimester Ultrasound Detection of Fetal Central Nervous System Anomalies

OBJECTIVE

To evaluate the potential of the first-trimester ultrasound (US) features for the detection of central nervous system (CNS) anomalies. Methods/Methodology: This is a prospective one-center three-year study. Unselected singleton pregnant women were examined using an extended first-trimester anomaly scan (FTAS) that included the CNS assessment: the calvaria shape, the septum (falx cerebri), the aspect of the lateral ventricles, the presence of the third ventricle and aqueduct of Sylvius (AS) and the posterior brain morphometry: the fourth ventricle, namely intracranial translucency (IT), brain stem/brain stem-occipital bone ratio (BS/BSOB) and cisterna magna (CM). The spine and underlying skin were also evaluated. The cases were also followed during the second and third trimesters of pregnancy and at delivery. FTAS efficiency to detect major CNS abnormalities was calculated.

RESULTS

We detected 17 cases with CNS major abnormalities in a population of 1943 first-trimester (FT) fetuses, including spina bifida with myelomeningocele, exencephaly-anencephaly, holoprosencephaly, hydrocephaly, cephalocele and Dandy-Walker malformation. The CNS features in the abnormal group are presented. In the second trimester (ST), we further diagnosed cases of corpus callosum agenesis, cerebellar hypoplasia, vein of Galen aneurysm and fetal infection features (ventriculomegaly, intraventricular bands, intraventricular cyst and hyperechoic foci), all declared normal at the FTAS. During the third trimester (TT) scan we identified a massive fetal cerebral haemorrhage absent at previous investigations. We report a detection rate of 72.7% of fetal brain anomalies in the FT using the proposed CNS parameters. The sensitivity of the examination protocol was 72.7%, and the specificity was 100%.

CONCLUSION

A detailed FT CNS scan is feasible and efficient. The majority of cases of major CNS abnormalities can be detected early in pregnancy. The visualization rates of the CNS parameters in the FT are great with short, if any, additional investigation time. FT cerebral disorders such as haemorrhage or infections were missed in the FT even when an extended evaluation protocol was used.

Presentation of ventriculomegaly at 11-14 weeks of gestation: An analysis of longitudinal data

OBJECTIVES

The aim of this study was to examine the value of the sonographic measurements of the choroid plexus and the lateral ventricles at 11-14 gestational weeks in fetuses that had the diagnosis of second-trimester ventriculomegaly (VM) as a clinical reference.

METHODS

The standard axial plane used for biparietal diameter measurement from 2D stored images in the first trimester was used to calculate the ratio between the choroid plexus and lateral ventricle diameter (PDVDR), the choroid plexus and lateral ventricle length (PLVLR) and the choroid plexus and lateral ventricle area (PAVAR) in 100 normal and 15 fetuses diagnosed with second-trimester VM.

RESULTS

In fetuses with VM, the measurements of PDVDR, PLVLR and PAVAR were all significantly smaller compared to normal fetuses (p = < 0.001, <0.001, <0.01). Four out of seven cases with mild VM had measurements below the 5th percentile (57%). 75% of cases with moderate or severe VM had at least one measurement below the 5th percentile.

CONCLUSIONS

Since the axial plane of the fetal head is obtained in all first-trimester routine screenings, the measurements of PDVDR, PLVLR and PAVAR could easily be integrated into routine examinations for an early detection of VM.

First trimester examination of fetal anatomy: clinical practice guideline by the World Association of Perinatal Medicine (WAPM) and the Perinatal Medicine Foundation (PMF)

This recommendation document follows the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation. We aim to bring together groups and individuals throughout the world for precise standardization to implement the ultrasound evaluation of the fetus in the first trimester of pregnancy and improve the early detection of anomalies and the clinical management of the pregnancy. The aim is to present a document that includes statements and recommendations on the standard evaluation of the fetal anatomy in the first trimester, based on quality evidence in the peer-reviewed literature as well as the experience of perinatal experts around the world.

Developmental Neuropathology and Neurodegeneration of Down Syndrome: Current Knowledge in Humans

Individuals with Down syndrome (DS) suffer from developmental delay, intellectual disability, and an early-onset of neurodegeneration, Alzheimer’s-like disease, or precocious dementia due to an extra chromosome 21. Studying the changes in anatomical, cellular, and molecular levels involved may help to understand the pathogenesis and develop target treatments, not just medical, but also surgical, cell and gene therapy, etc., for individuals with DS. Here we aim to identify key neurodevelopmental manifestations, locate knowledge gaps, and try to build molecular networks to better understand the mechanisms and clinical importance. We summarize current information about the neuropathology and neurodegeneration of the brain from conception to adulthood of foetuses and individuals with DS at anatomical, cellular, and molecular levels in humans. Understanding the alterations and characteristics of developing Down syndrome will help target treatment to improve the clinical outcomes. Early targeted intervention/therapy for the manifestations associated with DS in either the prenatal or postnatal period may be useful to rescue the neuropathology and neurodegeneration in DS.

First-trimester fetal neurosonography: technique and diagnostic potential

Most brain abnormalities are present in the first trimester, but only a few are detected so early in gestation. According to current recommendations for first-trimester ultrasound, the fetal head structures that should be visualized are limited to the cranial bones, the midline falx and the choroid-plexus-filled ventricles. Using this basic approach, almost all cases of acrania, alobar holoprosencephaly and cephalocele are detected. However, the majority of other fetal brain abnormalities remain undiagnosed until the midtrimester. Such anomalies would be potentially detectable if the sonographic study were to be extended to include additional anatomic details not currently included in existing guidelines. The aim of this review article is to describe how best to assess the normal fetal brain by first-trimester expert multiplanar neurosonography and to demonstrate the early sonographic findings that characterize some major fetal brain abnormalities. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Ratio of fetal choroid plexus to head size: simple sonographic marker of open spina bifida at 11-13 weeks' gestation

OBJECTIVES

To measure the ratio of choroid plexus (CP) size to head size in normal fetuses and to compare it to that in fetuses with open spina bifida (OSB) and quantify the subjective sign of a 'dry brain'.

METHODS

This was a retrospective study of ultrasound images, obtained during first-trimester screening between 11 and 13 weeks of gestation, from 34 fetuses with OSB and 160 normal fetuses. From the hospital databases, we retrieved images of the fetal head in the transventricular axial plane. We measured the areas of both CPs and the head and calculated the ratio between them. We also measured the longest diameter of each CP and calculated their mean (CP length), and measured the occipitofrontal diameter (OFD) and calculated the ratio of CP length to OFD. Measurements from the OSB fetuses were plotted on crown-rump length (CRL) reference ranges constructed using data from the normal fetuses, and Z-scores were calculated.

RESULTS

In the normal fetuses, the CP area increased, while the ratios of CP area to head area and CP length to OFD decreased, with increasing CRL. In 30 of the 34 (88%) fetuses with OSB, both ratios were increased significantly and the CPs filled the entirety of the head, giving the impression of a dry brain. In these cases, the borders of the lateral ventricles could not be identified.

CONCLUSIONS

At 11-13 weeks, the majority of fetuses with OSB have reduced fluid in the lateral ventricles such that the CPs fill the head. The dry brain sign is easily visualized during routine first-trimester ultrasound examination while measuring the biparietal diameter, and can be quantified by comparing the size of the CPs to the head size. Until prospective data confirm the usefulness of this sign in screening for OSB, it should be considered as a hint to prompt the examiner to assess thoroughly the posterior fossa and spine. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Subarachnoid space diameter in chromosomally abnormal fetuses at 11-13 weeks' gestation

OBJECTIVES

To examine the subarachnoid space diameters in chromosomally abnormal fetuses at 11-13 weeks' gestation.

METHODS

Stored three-dimensional (3D) ultrasound volumes of the fetal head at 11-13 weeks' gestation from 407 euploid and 88 chromosomally abnormal fetuses (trisomy 21, n = 40; trisomy 18, n = 19; trisomy 13, n = 7; triploidy, n = 14; Turner syndrome, n = 8) were analyzed. The subarachnoid space diameters, measured in the sagittal and transverse planes of the fetal head, in relation to biparietal diameter (BPD) in each group of aneuploidies was compared to that in euploid fetuses. A total of 20 head volumes were randomly selected and all the measurements were recorded by two different observers to examine the interobserver variability in measurements.

RESULTS

In euploid fetuses, the anteroposterior, transverse and sagittal diameters of the subarachnoid space increased with BPD. The median of the observed to expected diameters for BPD were significantly increased in triploidy and trisomy 13 but were not significantly altered in trisomies 21 and 18 or Turner syndrome. In triploidy, the subarachnoid space diameters for BPD were above the 95th centile of euploid fetuses in 92.9% (13 of 14) cases. The intraclass reliability or agreement was excellent for all three subarachnoid space diameters.

CONCLUSION

Most fetuses with triploidy at 11-13 weeks' gestation demonstrate increased subarachnoid space diameters.

First-trimester reference centiles of fetal biometry in Indian population

AIM AND OBJECTIVE

To create crown-rump length (CRL)-based biometric chart for fetus in the first trimester among the Indian population.

MATERIAL AND METHODS

Cross-sectional data were obtained from 400 singleton pregnancies between 11 and 14 weeks gestation with a normal outcome. Linear regression models were constructed; the mean and SD were derived as a function of CRL.

RESULTS

There was a positive correlation of CRL with nuchal translucency (NT) (y = 0.0102x + 0.6307 R²=0.1177), biparietal diameter (BPD) (BPD = 0.032*CRL +0.185 R²=0.765), occipito-frontal diameter (OFD), lateral ventricular diameter (LV), abdominal circumference (AC) (AC = 0.944*CRL +9.684 R²=0.668), femur length (FL) (FL = 0.222*CRL -4.734 R²=0.661), fetal weight (FW) (FW = 1.328*CRL -10.41 R²=0.662). The regression models and centile charts of NT, BPD, OFD, LV, AC, and FW were constructed. Taking FW as the independent variable, a linear equation of BPD, AC, and FL to calculate weight was constructed.

CONCLUSIONS

The first-trimester centile charts of fetal parameters can be used as a reference for Indian population in the determination of gestational age or other adverse outcomes.

Sonographic detection of central nervous system defects in the first trimester of pregnancy

The fetal central nervous system can already be examined in the first trimester of pregnancy. Acrania, alobar holoprosencephaly, cephaloceles, and spina bifida can confidently be diagnosed at that stage and should actively be looked for in every fetus undergoing first-trimester ultrasound. For some other conditions, such as vermian anomalies and agenesis of the corpus callosum, markers have been identified, but the diagnosis can only be confirmed in the second trimester of gestation. For these conditions, data on sensitivity and more importantly specificity and false positives are lacking, and one should therefore be aware not to falsely reassure or scare expecting parents based on first-trimester findings. This review summarizes the current knowledge of first-trimester neurosonography in the normal and abnormal fetus and gives an overview of which diseases can be diagnosed.

Approach to the sonographic evaluation of fetal ventriculomegaly at 11 to 14 weeks gestation

BACKGROUND

The aim of the study was to report the prevalence and associated findings of fetal ventriculomegaly between 11 + 0 and 13 + 6 gestational weeks and to evaluate a sonographic approach to classify first trimester ventriculomegaly in the standard axial plane used for biparietal diameter (BPD) measurement.

METHODS

The ratio between choroid plexus and lateral ventricle diameter (PDVDR), between the choroid plexus and lateral ventricle length (PLVLR) and between the choroid plexus and lateral ventricle area (PAVAR) were calculated from stored 2D images of the axial head plane in 100 normal fetuses and 17 fetuses with ventriculomegaly.

RESULTS

The PDVDR, the PLVLR and the PAVAR were below the 5(th) percentile in 82.4%, 94.1% and 94.1% of the cases with ventriculomegaly. Ventriculomegaly was isolated in 29.4% and associated with further anomalies in 70.6% at the initial evaluation. The mean PLVLR in euploid compared to aneuploid fetuses was significantly lower (0.40 versus 0.53 (p = 0.0332)).

CONCLUSIONS

The measurements of PDVDR, PLVLR and PAVAR are helpful to objectify ventriculomegaly at 11-14 gestational weeks. The PLVLR and PAVAR were superior to PDVDR, since there seems to be rather shrinkage of the choroid plexus than an increased width of the lateral ventricles in the first trimester.

Reference values for the right and left fetal choroid plexus at 11 to 13 weeks: an early sign of "developmental" laterality?

OBJECTIVES

The purpose of this study was to establish reference values for the length, area, and circumference of the right and left fetal choroid plexus at 11 to 13 weeks with respect to the fetal biparietal diameter and to compare the right to the left side.

METHODS

We conducted a prospective study on 114 fetuses at 11 to 13 weeks undergoing first-trimester screening for aneuploidy and structural fetal abnormalities. After the establishment of the fetal situs, the plane of the "butterfly" was obtained on all fetuses, from which the length, area, and circumference of both the right and left choroid plexus were obtained and the right and left sides compared. Using a paired t test, analysis of variance, scatterplots, and linear and logarithmic fittings, reference ranges and charts for the length, area, and circumference of the choroid plexus were then formulated according to their relationship to the fetal biparietal diameter. P < .05 was considered statistically significant.

RESULTS

Reference values for the length, area, and circumference of the fetal choroid plexus, with respect to the fetal biparietal diameter, were established. There was a statistically significant difference between the right and left sides for all parameters, with all measurements statistically greater on the left side (P < .0001).

CONCLUSIONS

Reference values for the length, area, and circumference of the fetal choroid plexus at 11 to 13 weeks are presented. These may prove to be of clinical importance in the early screening for central nervous system abnormalities. In addition, the statistically significant difference between the right and left sides may be an early sign of "developmental" laterality.

Prenatal Detection of Fetal Anomalies at the 11- to 13-Week Scan—Part I: Brain, Face and Neck

In the last 20 years, the role of first-trimester ultrasound screening has expanded from individual calculation of the risk of aneuploidy through measurement of the nuchal translucency to a powerful technique to evaluate important aspects of the fetal anatomy. Traditionally, the full anatomy scan for detection of structural anomalies has been performed in the second trimester of pregnancy. However, with the implementation of the first-trimester scan at 11 to 13 weeks of gestation many of the structural anomalies traditionally detected in the second trimester can now be identified earlier in pregnancy. In the first part of this review we discuss the main ultrasound findings that may facilitate the prenatal detection of fetal brain, face and neck abnormalities in the first trimester of pregnancy.

How to cite this article

Sepulveda W, Illescas T, Adiego B, Martinez-Ten P. Prenatal Detection of Fetal Anomalies at the 11- to 13-Week Scan—Part I: Brain, Face and Neck. Donald School J Ultrasound Obstet Gynecol 2013;7(4):359-368.