Prenatal diagnosis and pregnancy outcomes in fetuses with ventriculomegaly

Objective

Genetic etiology plays a critical role in fetal ventriculomegaly (VM). However, the studies on chromosomal copy number variants (CNVs) in fetal VM are limited. This study aimed to investigate the chromosomal CNVs in fetuses with mild to moderate VM, and explore its genotype-phenotype correlation.

Methods

A total of 242 fetuses with mild to moderate VM detected by prenatal ultrasound were enrolled in our study from October 2018 to October 2022. All cases underwent chromosomal microarray analysis (CMA) and G-banding simultaneously. All VM cases were classified different subgroups according to the maternal age, severity, VM distribution and presence/absence of other ultrasound abnormalities. The pregnancy outcomes and health conditions after birth were followed up. We also performed a pooled analysis regarding likely pathogenic and pathogenic CNVs (LP/P CNVs) for VM.

Results

The detection rate of chromosomal abnormalities by karyotyping was 9.1% (22/242), whereas it was 16.5% (40/242) when CMA was conducted (P < 0.05). The total detection rate of chromosomal abnormalities by karyotyping and CMA was 21.1% (51/242). A 12.0% incremental yield of CMA over karyotyping was observed. The detection rate of total genetic variants in fetuses with bilateral VM was significantly higher than in fetuses with unilateral VM (30.0% vs. 16.7%, P = 0.017). No significant differences were discovered between isolated VM and non-isolated VM, or between mild and moderate VM, or between advanced maternal age (AMA) and non-AMA (all P > 0.05). 28 fetuses with VM were terminated and 214 fetuses were delivered: one presented developmental delay and one presented congenital heart disease. The VM cases with both positive CMA and karyotypic results had a higher rate of termination of pregnancy than those with either a positive CMA or karyotypic result, or both negative testing results (P < 0.001).

Conclusion

The combination of CMA and karyotyping should be adopted to improve the positive detection rate of chromosomal abnormalities for VM. The total genetic abnormalities detected using both techniques would affect the final pregnancy outcomes. LP/P CNVs at 16p11.2, 17p13, and 22q11.21 were identified as the top three chromosomal hotspots associated with VM, which would enable genetic counselors to provide more precise genetic counseling for VM pregnancies.

Concordance between US and MRI Two-Dimensional Measurement and Volumetric Segmentation in Fetal Ventriculomegaly

We provide a study comparison between two-dimensional measurement and volumetric (3D) segmentation of the lateral ventricles and brain structures in fetuses with isolated and non-isolated ventriculomegaly with 3D virtual organ computer-aided analysis (VOCAL) ultrasonography vs. magnetic resonance imaging (MRI) analyzed with 3D-Slicer software. In this cross-sectional study, 40 fetuses between 20 and 38 gestational weeks with various degrees of ventriculomegaly were included. A total of 71 ventricles were measured with ultrasound (US) and with MRI. A total of 64 sonographic ventricular volumes, 80 ventricular and 40 fetal brain MR volumes were segmented and analyzed using both imaging modalities by three observers. Sizes and volumes of the ventricles and brain parenchyma were independently analyzed by two radiologists, and interobserver correlation of the results with 3D fetal ultrasound data was performed. The semiautomated rotational multiplanar 3D VOCAL technique was performed for ultrasound volumetric measurements. Results were compared to manually extracted ventricular and total brain volumes in 3D-Slicer. Segmentation of fetal brain structures (cerebral and cerebellar hemispheres, brainstem, ventricles) performed independently by two radiologists showed high interobserver agreement. An excellent agreement between VOCAL and MRI volumetric and two-dimensional measurements was established, taking into account the intraclass correlation coefficients (ICC), and a Bland-Altman plot was established. US and MRI are valuable tools for performing fetal brain and ventricular volumetry for clinical prognosis and patient counseling. Our datasets could provide the backbone for further construction of quantitative normative trajectories of fetal intracranial structures and support earlier detection of abnormal brain development and ventriculomegaly, its timing and progression during gestation.

Maternal blood inflammatory marker levels increased in fetuses with ventriculomegaly

Background

Fetal ventriculomegaly (VM) is one of the most common abnormalities of the central nervous system (CNS), which can be significantly identified by brain anomalies prenatally by magnetic resonance imaging (MRI). Aberrant white blood cells (WBCs) levels indicate that the maternal is suffering from the infection. Previous studies have confirmed that prenatal infection can affect fetal brain structure, but there is no research revealed the association between maternal blood parameters with fetal VM until now.

Methods

We measured the width of the lateral ventricle of 142 fetuses, which were divided into the fetal VM group (n = 70) and the normal lateral ventricle group (n = 72). We compared maternal blood cell levels between the two groups and investigate potential biomarkers of fetal VM.

Result

High levels of maternal WBC and neutrophil (NE#) levels were observed in fetuses with VM (p < 0.001), while lymphocyte percentage, monocytes (MO#), neutrophil/lymphocyte ratio (NLR), and platelet were also increased in the fetal VM group (p = 0.033, 0.027, 0.034, and 0.025, respectively). receiver-operator curve (ROC) analysis suggested that WBC and NE# counts might be useful to distinguish fetuses with enlarged lateral ventricles (AUC = 0.688, 0.678, respectively).

Conclusion

The current study emphasizes the importance of maternal infection for fetal brain growth, which could provide important information for prenatal diagnosis of CNS anomalies. Future research needs longitudinal analysis and exploration of the influence of maternal blood inflammatory marker levels on fetal brain development.

Prenatal findings and associated survival rates in fetal ventriculomegaly: A prospective observational study

OBJECTIVES

Fetal ventriculomegaly is associated with varying degrees of genetic and structural abnormalities. The objective was to present the experience of fetal ventriculomegaly in a large European center in relation to: 1. grade of ventriculomegaly; 2. additional chromosomal/structural abnormalities; and 3. perinatal survival rates.

METHODS

This was a prospective observational study of patients referred with fetal ventriculomegaly from January 2011 to July 2020. Data were obtained from the hospital database and analyzed to determine the rate of isolated ventriculomegaly, associated structural abnormalities, chromosomal/genetic abnormalities, and survival rates. Data were stratified into three groups; mild (Vp = 10-12 mm), moderate (Vp = 13-15 mm) and severe (Vp > 15 mm) ventriculomegaly.

RESULTS

There were 213 fetuses included for analysis. Of these 42.7% had mild ventriculomegaly, 44.6% severe and 12.7% had moderate ventriculomegaly. Initial ultrasound assessment reported isolated ventriculomegaly in 45.5% fetuses, with additional structural abnormalities in 54.5%. The rate of chromosomal/genetic abnormalities was high,16.4%. After all investigations, the true rate of isolated VM was 36.1%. The overall survival was 85.6%. Survival was higher for those with isolated VM across all groups (P < 0.05).

CONCLUSION

Ventriculomegaly is a complex condition and patients should be counselled that even with apparently isolated VM, there remains the possibility of additional genetic and/or structural problems being diagnosed in up to 10% of fetuses.

Prenatal Ventriculomegaly - Diagnosis, Prognostication and Management

Fetal ventriculomegaly (VM) refers to the abnormal enlargement of one or more ventricles of the brain in-utero. The enlargement may or may not be related to ventricular obstruction and increased intracranial pressure; therefore, the term "hydrocephalus" is not used. VM is diagnosed usually in the mid-trimester when the atrial diameter (AD) of the lateral ventricle is more than 10 mm on one or both sides. A thorough workup is then required to identify the cause as the etiology is diverse. Fetal magnetic resonance imaging (MRI) may yield additional information. Serial ultrasound follow-up would be required to assess its progression with advancing gestation. The prognosis and long-term outcomes greatly depend upon the etiology, the severity at diagnosis, progression, and associations. This article reviews the definitions, diagnosis, and workup of fetal VM, discusses follow-up protocols and prognosis, and examines the role of fetal therapy, including fetoscopic surgery in its prenatal management.

Ventriculo-amniotic shunting for severe fetal ventriculomegaly

INTRODUCTION

Severe fetal cerebral ventriculomegaly, observed in about 1 in 1000 newborns, is associated with a high risk of perinatal death and neurodevelopmental delay in survivors. The objective of this study was to evaluate the efficiency of ventriculo-amniotic shunting for drainage of severe fetal cerebral ventriculomegaly and the neurodevelopment of survivors at the age of 2 years.

MATERIAL AND METHODS

This was a retrospective study of 44 fetuses with severe bilateral ventriculomegaly treated with ventriculo-amniotic shunting in a tertiary fetal therapy center between 2010 and 2015.

RESULTS

Shunt insertion was successfully carried out at a median gestational age of 25 weeks (range 20-33 weeks). There were three fetal deaths within 24 hours of the procedure and 41 live births at a median gestational age of 37 weeks (range 28-39 weeks). Neurodevelopment at 2 years of age was evaluated using the Bayley scale in the 38 survivors. In the 27 cases with isolated ventriculomegaly 19 (70.4%; 95% confidence interval [95% CI] 51.5%-84.2%) had normal or mild neurodevelopmental delay and 8 (29.6%; 95% CI 15.6%-48.5%) were moderately or severely delayed. In the 11 with non-isolated ventriculomegaly 2 (18.2%; 95% CI 5.1%-4.8%) had normal or mild neurodevelopmental delay and 9 (81.8%; 95% CI 52.3%-94.9%) babies were moderately or severely delayed.

CONCLUSIONS

Ventriculo-amniotic shunting is an option for the management of severe ventriculomegaly and results in normalization of the ventricular diameter. However, a high proportion of survivors have neurodevelopmental delay and the possible beneficial effect of ventriculo-amniotic shunting needs to be assessed by randomized studies.

Correlations of atrial diameter and frontooccipital horn ratio with ventricle size in fetal ventriculomegaly

OBJECTIVE Fetal ventriculomegaly (FV), or enlarged cerebral ventricles in utero, is defined in fetal studies as an atrial diameter (AD) greater than 10 mm. In postnatal studies, the frontooccipital horn ratio (FOHR) is commonly used as a proxy for ventricle size (VS); however, its role in FV has not been assessed. Using image analysis techniques to quantify VS on fetal MR images, authors of the present study examined correlations between linear measures (AD and FOHR) and VS in patients with FV. METHODS The authors performed a cross-sectional study using fetal MR images to measure AD in the axial plane at the level of the atria of the lateral ventricles and to calculate FOHR as the average of the frontal and occipital horn diameters divided by the biparietal distance. Computer software was used to separately segment and measure the area of the ventricle and the ventricle plus the subarachnoid space in 2 dimensions. Segmentation was performed on axial slices 3 above and 3 below the slice used to measure AD, and measurements for each slice were combined to yield a volume, or 3D VS. The VS was expressed as the absolute number of voxels (non-normalized) and as the number of voxels divided by intracranial size (normalized). A Pearson correlation coefficient was used to measure the strength of the relationships between the linear measures and the size of segmented regions in 2 and 3 dimensions and over various gestational ages (GAs). Differences between correlations were compared using Steiger's z-test. RESULTS Fifty FV patients who had undergone fetal MRI between 2008 and 2014 were included in the study. The mean GA was 26.3 ± 5.4 weeks. The mean AD was 18.1 ± 8.3 mm, and the mean FOHR was 0.49 ± 0.11. When using absolute VS, the correlation between AD and 3D VS (r = 0.844, p < 0.0001) was significantly higher than that between FOHR and 3D VS (r = 0.668, p < 0.0001; p = 0.0004, Steiger's z-test). However, when VS was normalized, correlations were not significantly different between AD and 3D VS (r = 0.830, p < 0.0001) or FOHR and 3D VS (r = 0.842, p < 0.0001; p = 0.8, Steiger's z-test). For GAs of 24 weeks or earlier, AD correlated more strongly with normalized 3D VS (r = 0.902, p < 0.0001) than with FOHR (r = 0.674, p < 0.0001; p < 0.0001, Steiger's z-test). After 24 weeks, there was no difference in correlations between linear measures (AD or FOHR) and 3D VS (r > 0.9). Correlations of linear measures with VS in 2 and 3 dimensions were similar, and inclusion of the subarachnoid space did not significantly alter results. CONCLUSIONS Findings in the study support the use of AD as a measure of VS in fetal studies as it correlates highly with both absolute and relative VS, especially at early GAs, and captures the preferential dilation of the occipital horns in patients with FV. Compared with AD, FOHR similarly correlates with normalized VS and, after a GA of 24 weeks, can be reported in fetal studies to provide continuity with postnatal monitoring.