Is fetal magnetic resonance imaging indicated when ultrasound isolated mild ventriculomegaly is present in pregnancies with no risk factors?

Natural history and mid-term neurodevelopmental outcome of fetuses with isolated mild ventriculomegaly diagnosed in the second half of pregnancy

INTRODUCTION

Prenatal diagnosis and counseling of isolated ventriculomegaly (VM) represent a considerable challenge. We aimed to analyze the intrauterine evolution, associated anomalies, and neurodevelopmental outcome using the Battelle Development Inventory (BDI) of fetuses with an initial diagnosis of isolated mild VM.

MATERIAL AND METHODS

Retrospective cohort study of fetuses diagnosed with mild isolated VM (10 -12 mm) between 2012 and 2016 in a tertiary hospital. In 2018, parents were invited to complete the structured BDI test for the neurodevelopmental evaluation of their children in five domains (personal-social skills, adaptive behavior, psychomotor ability, communication, and cognition). Results exceeding two standard deviations were considered abnormal and referred to an expert neuropediatrician.

RESULTS

We identified 43 cases of mild isolated VM. In 5 (11%), structural abnormalities were detected during prenatal follow-up, being related to non-regressive forms (p = .01) and bilateral VM (p = .04). The BDI test was completed by 19/43 (44%). The global score was abnormal in 10/19 (53%). Of them, the neuropediatrician confirmed a neurodevelopmental delay solely in 3 cases that had already been diagnosed with neurological disorders. The most affected domains were gross motor skills (63%), personal-social (63%), and adaptive domains (47%). Communicative and cognitive areas were abnormal in 26% of cases.

CONCLUSION

In fetuses with isolated mild VM detected in the second half of pregnancy, 53% had an abnormal BDI test at 2-6 years, but a neurological disorder was only confirmed in the 30% of them.

Fetal cerebral ventriculomegaly: What do we tell the prospective parents?

Fetal cerebral ventriculomegaly is a relatively common finding, observed during approximately 1% of obstetric ultrasounds. In the second and third trimester, mild (≥10 mm) and severe ventriculomegaly (≥15 mm) are defined according to the measurement of distal lateral ventricles that is included in the routine sonographic examination of central nervous system. A detailed neurosonography and anatomy ultrasound should be performed to detect other associated anomalies in the central nervous system and in other systems, respectively. Fetal MRI might be useful when neurosonography is unavailable or suboptimal. The risk of chromosomal and non-chromosomal genetic disorders associated with ventriculomegaly is high, therefore invasive genetic testing, including microarray, is recommended. Screening for prenatal infections, in particular cytomegalovirus and toxoplasmosis, should also be carried out at diagnosis. The prognosis is determined by the severity of ventriculomegaly and/or by the presence of co-existing abnormalities. Fetal ventriculoamniotic shunting in progressive isolated severe ventriculomegaly is an experimental procedure. After delivery, ventricular-peritoneal shunting or ventriculostomy are the two available options to treat hydrocephalus in specific conditions with similar long-term outcomes. A multidisciplinary fetal neurology team, including perinatologists, geneticists, pediatric neurologists, neuroradiologists and neurosurgeons, can provide parents with the most thorough prenatal counseling. This review outlines the latest evidence on diagnosis and management of pregnancies complicated by fetal cerebral ventriculomegaly.

Contribution of fetal magnetic resonance imaging in the evaluation of neurosonographically detected cases of isolated mild and moderate cerebral ventriculomegaly

AIM

This study aimed to present the contribution of prenatal magnetic resonance imaging (MRI) in the diagnosis of fetuses that were previously identified as isolated mild and moderate cerebral ventriculomegaly (VM) by ultrasound (US).

METHODS

The data between February 2013 and August 2020 were collected for women who were diagnosed with isolated mild or moderate fetal VM by US and subsequently underwent a fetal MRI.

RESULTS

Among 321 women, 21 (6.5%) had a clinically important additional finding after MRI. Twelve of 276 (4.3%) fetuses with mild VM and 9 of 45 (20%) with moderate VM had turned out to have additional central nervous system abnormalities. Additional findings were detected more in fetuses with moderate VM, mothers with an anterior-located placenta, and mothers with higher body mass indexes (BMIs) with statistical significance (p = 0.001, p = 0.013, p = 0.036, respectively). The most common additional MRI finding was grade 3 or 4 germinal matrix hemorrhage, which was detected in 11 of 21 fetuses (52.3%).

CONCLUSIONS

Considering the countries' health policies, prenatal MRI would contribute mostly to the diagnosis of fetuses with moderate VM, pregnancies with anterior-located placenta, and mothers with high BMIs. According to our data, we believe that MRI will be valuable, especially in the diagnosis of grade 3 and 4 intracranial hemorrhage group.

Diagnosis, management, and neurodevelopmental outcomes of fetal hydrocephalus: an observational prospective study

The etiology of fetal hydrocephalus is complex, and the outcome of fetal neurodevelopment after birth is also different. The purpose of this study is to conduct anti-infection of hydrocephalus fetuses with non-specific infection, and observe their neurodevelopment after birth, so as to provide clinical basis for further guidance and management of fetal hydrocephalus. Eighteen single pregnant women with fetal hydrocephalus confirmed by intrapartum ultrasonography in the Second Xiangya Hospital between July 1, 2019, and December 1, 2020, were included. Pelvis MRI, NITP, amniotic fluid/umbilical cord blood puncture, infection index, TORCH, and other examinations were completed during pregnancy. If the patient's infection index is elevated, the second-generation cephalosporin will be used for anti-infection therapy, and the development of fetal hydrocephalus, growth, and neurodevelopment after birth will be observed. Fetal hydrocephalus subsided in 3 cases (25%, 95% CI [0%, 53.7%]) remained stable in 6 cases (50%, 95% CI [16.8%, 83.2%]), progressed in 2 cases (16.7%, 95% CI [0%, 41.4%]), and terminated pregnancy in 1 case (8.7% [0%, 26.7%]). Of the 6 untreated patients, pregnancy was terminated in 3 (50%), hydrocephalus remained stable in 2 (33.3%), and spontaneous resolution in 1 case (16.7%). Fourteen patients delivered successfully, including 11 children with no obvious abnormalities in growth and development, 1 with mild growth retardation and 2 with moderate growth retardation. Anti-infective therapy in the case of non-specific infection or maternal infection can partially prevent the progression of hydrocephalus.

Diagnosis of central nervous system abnormalities: comparison of prenatal neurosonography and foetal magnetic resonance imaging findings

Magnetic resonance imagining (MRI) is gradually becoming the more preferred imaging modality in the evaluation of central nervous system (CNS) abnormalities rather than foetal ultrasonography (USG). The aim of this study was to compare the findings of prenatal neurosonography and foetal MRI. The study was a retrospective study analysing the records of 160 pregnant women who underwent both foetal MRI and USG due to suspicion of CNS abnormalities between 2008 and 2019. Indications for applying foetal MRI were neurosonography and foetal MRI findings. When the compatibility between MRI and USG results was examined in CNS abnormalities, it was found fully compatible in 61.3% of cases, partially compatible in 24.53% of cases, and not compatible in 14.5% of cases. When comparing prenatal neurosonography and foetal MRI findings, additional findings were reported in 16.9% of cases, and no additional finding was reported in 66.8% of cases. While normal anatomical findings were reported in 8.8% of the cases in MRI, the diagnosis made by neurosonography changed in 7.5%. Foetal MRI has more advantages than USG both in imaging the CNS abnormalities in more detail and in determining the accompanying additional anomalies.IMPACT STATEMENTWhat is already known on this subject: USG is a safe, practical and cost-effective primary imaging method that is widely used for foetal anomaly screening. However, there may sometimes be difficulties in evaluating the foetal brain structures due to foetal position which is unsuitable for imaging, extremely obese with a high body mass index, oligohydramnios and ossified foetal skull. For this reason, magnetic resonance imaging (MRI) is used as the most commonly used imaging method after USG in the evaluation of foetal anatomy, especially CNS.What do the results of this study add?: In our study, we saw that foetal MRI has more advantages than neurosonography in both seeing CNS abnormalities in more detail and recognising additional anomalies that may accompany.What are the implications of these findings for clinical practice and/or further research?: We have seen that besides neurosonography, foetal MRI can provide important information that can affect the clinical approach in pregnancy management by increasing the correct diagnosis in pregnancies with congenital CNS abnormalities. MRI: it is the best secondary imaging modality that can aid diagnosis in addition to neurosonography in the diagnosis of CNS abnormalities and in suspected cases. Therefore, foetal MRI should be used more widely in prenatal diagnosis.

Fetal US and MRI in detection of craniospinal anomalies with postnatal correlation: single-center experience

Background/aim

To reveal the contribution of magnetic resonance imaging (MRI) to ultrasound (US) in prenatal diagnosis of fetal craniospinal anomalies by retrospectively comparing the prenatal and postnatal findings.

Materials and methods

After institutional review board approval, between January 2010 and May 2020, 301 pregnant women, which had a gestational age between 19–37 weeks (mean 26.5 ± 6.1 weeks), diagnosed with cranial and spinal anomalies on fetal US and later on imaged with MRI were evaluated, and in 179 of those cases prenatal imaging findings were compared with postnatal findings.

Results

A total of 191 fetal craniospinal anomalies were detected in 179 pregnant women. MRI and US diagnosis were completely correct in 145 (75.9%) and 112 (58.6%), respectively. Diagnostic performance of MRI was significantly higher than that of the US (p < 0.05). Both prenatal MRI and US findings were concordant with postnatal diagnosis in 53% of the cases. In 28.7% cases, prenatal MRI contributed to US by either changing the wrong US diagnosis (8.9%), demonstration of additional findings (14%), or confirming the suspicious US diagnosis (5.8%).

Conclusion

Due to its high resolution and multiplanar imaging capability, fetal MRI contributes significantly to US in the correct prenatal diagnosis of craniospinal anomalies. This contribution especially is significant in neural tube defects, cortical malformations, and ischemic-hemorrhagic lesions.

Brain fetal neuroradiology: a beginner's guide

The importance of fetal magnetic resonance imaging (MRI) in the prenatal diagnosis of central nervous system (CNS) anomalies is rapidly increasing. Fetal MRI represents a third level examination usually performed, as early as 18-20 weeks of gestational age, when a second level (expert) neuro-ultrasonography (US) evaluation raises the suspicion of a CNS anomaly or when a genetic disorder is known. Compared to the US, MRI has the advantage to allow a better visualization and characterization of brain structures so to detect anomalies not visible in the US, thus resulting in relevant implications for parent counselling and pregnancy management. Moreover, the improvement of MRI technologies permits to obtain ultrafast sequences, which minimize the drawback of movement artifacts, and to perform advanced studies. This review aims at providing a practical guide for trainees and fellows who are approaching fetal MRI. In the first part, we provide information about indications, safety and protocols based on the state-of-the-art sequences, with a mention on the innovations related to the use of a 3T scanner. The second part is focused on the normal development of the human fetal brain related to its MR appearance, whose knowledge is essential to detect possible abnormalities. The last section briefly describes the most frequent abnormalities in the fetal brain and spine as depicted by MRI.

Outcomes of Isolated Fetal Ventriculomegaly That Resolve In Utero

OBJECTIVE

Isolated fetal ventriculomegaly is often an incidental finding on antenatal ultrasound. It is benign in up to 90% of cases, although it can be associated with genetic, structural, and neurocognitive disorders. The literature suggests that over 40% of isolated mild ventriculomegaly will resolve in utero, but it is unclear if resolution decreases the associated risks.The aim of this study is to compare the fetal and neonatal genetic outcomes of ventriculomegaly that persists or resolves on subsequent ultrasound.

STUDY DESIGN

This is a retrospective cohort study of women diagnosed with isolated ventriculomegaly via fetal ultrasound at a tertiary referral center between 2011 and 2019. Patients were excluded if other structural anomalies were identified on ultrasound.

RESULTS

A total of 49 patients were included in the study, 19 in the resolved ventriculomegaly group and 30 in the persistent ventriculomegaly group. Women in the resolved ventriculomegaly group were more likely to be diagnosed earlier (24 vs. 28 weeks, p = 0.007). Additionally, they were more likely to have mild ventriculomegaly (63 vs. 84%, p = 0.15), and less likely to have structural neurological abnormalities diagnosed on postnatal imaging (5 vs. 17%, p = 0.384), although these were not statistically significant. Aneuploidy risk for resolved compared with persistent ventriculomegaly was similar (5 vs. 7%, p = 0.999).

CONCLUSION

This study suggests that resolution of isolated ventriculomegaly in utero may not eliminate the risk of genetic or chromosomal abnormalities in this population and may warrant inclusion as part of the counselling of these at-risk patients. Larger prospective studies are needed to confirm these findings.

KEY POINTS

· Ventriculomegaly is known to be associated with genetic and chromosomal abnormalities.. · Resolution of the ventriculomegaly in utero may not eliminate those risks.. · Patients with resolved ventriculomegaly should be offered aneuploidy screening or testing..

Sonographic spectrum and postnatal outcomes of early-onset versus late-onset fetal cerebral ventriculomegaly

OBJECTIVES

To review the prenatal characteristics and postnatal outcomes of Early-onset and Late-onset cerebral ventriculomegaly (VM).

METHODS

Single-center retrospective study 2013-2017; VM cases grouped into Early-onset VM (EVM; Diagnosis at/before 24 weeks) and Late-onset VM (LVM; Beyond 24 weeks). LVM cases had normal ventricle width measurement at mid-trimester scan. Infection serology, cytogenetics, MRI, sonographic follow-up, perinatal and neurodevelopmental outcomes were analyzed.

RESULTS

During the 5-year period, 64,662 women underwent an anomaly screening scan and 302 fetuses were identified with ventriculomegaly; 183 (60.6%) classified as early-onset and 119 (39.4%) LVM. The mean ventricular width was significantly higher in LVM cohort (14.1 mm vs 11.6 mm; p < .01). EVM cases were more often associated with structural anomalies (p < .05). Possible etiologies for EVM were aneuploidy and cerebral malformations like Absent Corpus Callosum, spina bifida, Dandy-Walker malformation, etc., whereas LVM followed aqueductal stenosis, hemorrhage, porencephaly, cerebral tumors, etc. Pregnancy outcomes were available for 251 cases. The pregnancy resulted in more live births in LVM group (87.4% vs 65.6%, p = < .01). Multivariate regression analysis demonstrated additional malformations (p < .0001, OR11.5 [95%CI: 4-35.2]), progression of VM (p = .004, OR 10.2 [95% CI: 2.1-52.3]) and severity of VM (OR 5.3 [95%CI: 0.8-37.7]) were significant predictors of Neurodevelopmental Impairment (NDI). Late gestation at diagnosis was more often associated with NDI (p = .063, OR2.4 [95%CI: 0.9-6.2]), although statistically insignificant.

CONCLUSIONS

EVM has a significantly different sonographic spectrum and outcomes compared to LVM. EVM is milder and associated with an increased risk of aneuploidy and structural malformations. LVM often occurs secondary to acquired brain lesions.

Prenatal diagnosis of chromosomal aberrations by chromosomal microarray analysis in foetuses with ventriculomegaly

Ventriculomegaly is considered to be linked to abnormal neurodevelopment outcome. The aim of this retrospective study was to investigate the current applications of chromosomal microarray analysis (CMA) in foetuses with ventriculomegaly. A total of 548 foetuses with ventriculomegaly detected by prenatal ultrasound underwent single nucleotide polymorphism (SNP) array testing and were subjected to long-term follow-up. The overall prevalence of chromosomal aberrations was 7.30% (40/548), including 4.20% (23/548) with pathogenic/likely pathogenic copy number variants. The incidence of chromosomal aberrations was significantly higher in foetuses with bilateral ventriculomegaly than in those with unilateral ventriculomegaly (10.56% vs. 5.71%, P = 0.040), in foetuses with non-isolated ventriculomegaly than in those with isolated ventriculomegaly (12.99% vs. 2.38%, P < 0.0001), and in foetuses with severe ventriculomegaly than in those with mild-to-moderate ventriculomegaly (23.08% vs. 6.51%, P = 0.005). The outcome in foetuses with mild ventriculomegaly was significantly better than in those with moderate ventriculomegaly (95.60% vs. 84.00%, P = 0.003). Thus, CMA should be regarded as the first-tier test for prenatal diagnosis of foetal ventriculomegaly, especially in foetuses with bilateral or non-isolated ventriculomegaly. The outcome of foetuses with mild ventriculomegaly is favourable; however, there is an increased risk of neurodevelopmental disabilities in foetuses with moderate ventriculomegaly.

Significance of isolated borderline ventriculomegaly

PURPOSE

Foetal ventriculomegaly (VM) is one of the most commonly diagnosed brain abnormalities. The aims of this study were to assess cases with isolated VM, describe the prenatal course and assess short- and long-term follow-up at the age of 2 years.

METHODS

We performed a retrospective analysis from our prenatal data base and included all children that were prenatally diagnosed with VM in our unit between 2008 and 2013 (n = 250). Prenatal management, postnatal outcome and neurologic development at the age of 2 years were evaluated.

RESULTS

A total of 106 children were born at our institution and were diagnosed prenatally with isolated borderline VM. A total of 1.9% (n = 2/106) was transferred to the neonatal unit. A total of 0.9% (n = 1/106) showed abnormal findings in postnatal brain ultrasound. A total of 1.9% (n = 2/106) showed mild neurologic abnormalities after birth, but none had to be seen by a neuropediatrician. At the follow-up at 2 years, 2.5% (n = 1/40) had an insertion of a shunt.

CONCLUSION

Based on our analysis, the majority of isolated borderline VM do not show short- or long-term neurological abnormalities. However, all cases of VM should be referred to a detailed prenatal ultrasound exam by a specialist.

Role of magnetic resonance imaging in fetuses with mild or moderate ventriculomegaly in the era of fetal neurosonography: systematic review and meta-analysis

OBJECTIVES

To report the rate of additional central nervous system (CNS) anomalies detected exclusively on prenatal magnetic resonance imaging (MRI) in fetuses diagnosed with isolated mild or moderate ventriculomegaly (VM) on ultrasound, according to the type of ultrasound protocol adopted (dedicated neurosonography vs standard assessment of the fetal brain), and to explore whether the diagnostic performance of fetal MRI in detecting such anomalies is affected by gestational age at examination and laterality and degree of ventricular dilatation.

METHODS

MEDLINE, EMBASE, CINAHL and Clinicaltrials.gov were searched for studies reporting on the prenatal MRI assessment of fetuses diagnosed with isolated mild or moderate VM (ventricular dilatation of 10-15 mm) on ultrasound. Additional anomalies detected only on MRI were classified as callosal, septal, posterior fossa, white matter, intraventricular hemorrhage, cortical, periventricular heterotopia, periventricular cysts or complex malformations. The rate of additional anomalies was compared between fetuses diagnosed on dedicated neurosonography, defined as a detailed assessment of the fetal brain, according to the International Society of Ultrasound in Obstetrics and Gynecology guidelines, and those diagnosed on standard fetal brain assessment. The rate of additional CNS anomalies missed on prenatal MRI and detected only at birth was calculated and compared between fetuses that had early (at or before 24 weeks' gestation) and those that had late (after 24 weeks) MRI. Subanalysis was performed according to the laterality (uni- vs bilateral) and degree (mild vs moderate, defined as ventricular dilatation of 10-12 and 13-15 mm, respectively) of ventricular dilatation. Whether MRI assessment led to a significant change in prenatal management was explored. Random-effects meta-analysis of proportions was used.

RESULTS

Sixteen studies (1159 fetuses) were included in the systematic review. Overall, MRI detected an anomaly not identified on ultrasound in 10.0% (95% CI, 6.2-14.5%) of fetuses. However, when stratifying the analysis according to the type of ultrasound assessment, the rate of associated anomalies detected only on MRI was 5.0% (95% CI, 3.0-7.0%) when dedicated neurosonography was performed compared with 16.8% (95% CI, 8.3-27.6%) in cases that underwent a standard assessment of the fetal brain in the axial plane. The overall rate of an additional anomaly detected only at birth and missed on prenatal MRI was 0.9% (95% CI, 0.04-1.5%) (I² , 0%). There was no difference in the rate of an associated anomaly detected only after birth when fetal MRI was carried out before, compared with after, 24 weeks of gestation (P = 0.265). The risk of detecting an associated CNS abnormality on MRI was higher in fetuses with moderate than in those with mild VM (odds ratio, 8.1 (95% CI, 2.3-29.0); P = 0.001), while there was no difference in those presenting with bilateral, compared with unilateral, dilatation (P = 0.333). Finally, a significant change in perinatal management, mainly termination of pregnancy owing to parental request, following MRI detection of an associated anomaly, was observed in 2.9% (95% CI, 0.01-9.8%) of fetuses undergoing dedicated neurosonography compared with 5.1% (95% CI, 3.2-7.5%) of those having standard assessment.

CONCLUSIONS

In fetuses undergoing dedicated neurosonography, the rate of a CNS anomaly detected exclusively on MRI is lower than that reported previously. Early MRI has an excellent diagnostic performance in identifying additional CNS anomalies, although the findings from this review suggest that MRI performed in the third trimester may be associated with a better detection rate for some types of anomaly, such as cortical, white matter and intracranial hemorrhagic anomalies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Current Controversies in Prenatal Diagnosis 1: Should MRI be performed on all fetuses with mild ventriculomegaly?

A ventricular diameter of 10 mm correlates with more than two standard deviations of the normal and hence is qualified as ventriculomegaly. The relevance of this is dependent on whether there are associated infectious, genetic, or structural problems. The chance for neurodevelopmental delay in isolated ventriculomegaly less than 15 mm is 7.9% (4.7-11.1), and less if it is unilateral. It can be further divided in mild (10-12) or moderate (13-15), though this is not widely accepted. As part of the workup, structural assessment today may include ultrasound or magnetic resonance imaging, or both. Discussants agreed that the diagnostic performance of both methods is as good as the expertise with which the images are acquired and interpreted. Discussants agreed that when the initial neurosonogram is normal, the likelihood of finding significant findings on MRI is low. Nevertheless, some anomalies may only be picked up or better worked out by fetal MRI. In utero follow-up is advocated, as progression may indicate a poorer outcome, and some conditions are only obvious late in pregnancy. Most benefit for future patients is expected from appropriate training in prenatal neuroimaging.

Mild ventriculomegaly from fetal consultation to neurodevelopmental assessment: A single center experience and review of the literature

OBJECTIVE

The aim of our study was to determine the outcome of fetuses with isolated mild ventriculomegaly, with prenatal imaging work-up, prenatal consultation, delivery and clinical follow-up performed in a single tertiary referring center.

METHODS

Fetuses with isolated and non-progressive mild ventriculomegaly (10-15 mm) were included in the study. Inclusion criteria were as follows: singleton pregnancies, normal chromosomal analysis, normal serological evaluation of TORCH, fetal ultrasound and MRI excluding additional CNS or extra-CNS malformations. The prenatal consultation consisted in discussing the prognosis of ventriculomegaly, according to the literature. The postnatal follow-up protocol included a neuroradiological investigation (cranial ultrasound or MRI), neurological and pediatric examinations. The Griffiths Scales were used to assess the neurodevelopmental outcome.

RESULTS

Thirty newborns were included in follow-up. The postnatal neuroradiological investigations confirmed the ventriculomegaly as an isolated finding in all cases except one. Nineteen children were available for formal neurodevelopmental testing. In our case series, 93.3% of the children had a favorable outcome or mild anomalies. Two children (6.6%) with mild ventriculomegaly were diagnosed as having rare genetic conditions. The Griffiths developmental quotients were normal (mean General Quotient 98.3) at the latest assessment (mean age 20.8 months) in all but one case.

DISCUSSION

Most children in our case series had a favorable outcome, as described in the literature. Even though a large quantity of data is now available on ventriculomegaly, fetal consultation remains challenging and requires caution. The diagnostic work-up of pregnancies diagnosed with mild ventriculomegaly must be very meticulous and include TORCH evaluation, microarray, serial ultrasounds to exclude progression, and a fetal MRI. However, despite accurate screening, there are more complex conditions in which ventriculomegaly can be the only non-specific finding in fetal life, making postnatal follow up mandatory.

Utility of prenatal MRI in the evaluation and management of fetal ventriculomegaly

OBJECTIVE

Fetal ventriculomegaly may occur in isolation or as part of a broader syndrome. We aimed to determine the added value of magnetic resonance imaging (MRI) for informing the pre-natal and postnatal care of pregnancies complicated by ventriculomegaly (VM).

STUDY DESIGN

Retrospective analysis of all cases of prenatally diagnosed VM referred to the fetal center at Lucile Packard Children's Hospital Stanford 1/1/2009-6/1/2014 were reviewed. Ultrasound (US) and MRI findings were reviewed, and the added yield of MRI evaluated.

RESULTS

A total of 91 cases of fetal VM were identified and 74 (81%) underwent MRI. In 62/74 (84%) cases, additional CNS or non-CNS findings, not seen on US, were discovered on MRI, of which 58 were CNS-related. Forty-six (62%) of the additional findings were considered clinically relevant, of which 45 were CNS-related.

CONCLUSION

Fetal MRI identifies additional, clinically relevant CNS and non-CNS findings in a majority of cases of VM following initial US.

Mild fetal ventriculomegaly: diagnosis, evaluation, and management

Ventriculomegaly is defined as dilation of the fetal cerebral ventricles and is a relatively common finding on prenatal ultrasound. The purpose of this document is to review the diagnosis, evaluation, and management of mild fetal ventriculomegaly. When enlargement of the lateral ventricles (≥10 mm) is identified, a thorough evaluation should be performed, including detailed sonographic evaluation of fetal anatomy, amniocentesis for karyotype and chromosomal microarray analysis, and a workup for fetal infection. In some cases, fetal magnetic resonance imaging may identify other central nervous system abnormalities and should be considered when this technology as well as expert interpretation is available. Follow-up ultrasound examination should be performed to assess for progression of the ventricular dilation. In the setting of isolated ventriculomegaly of 10-12 mm, the likelihood of survival with normal neurodevelopment is >90%. With moderate ventriculomegaly (13-15 mm), the likelihood of normal neurodevelopment is 75-93%. The following are Society for Maternal-Fetal Medicine recommendations: We suggest that ventriculomegaly be characterized as mild (10-12 mm), moderate (13-15 mm), or severe (>15 mm) for the purposes of patient counseling, given that the chance of an adverse outcome and potential for other abnormalities are higher when the ventricles measure 13-15 mm vs 10-12 mm (GRADE 2B); we recommend that diagnostic testing (amniocentesis) with chromosomal microarray analysis should be offered when ventriculomegaly is detected (GRADE 1B); we recommend testing for cytomegalovirus and toxoplasmosis when ventriculomegaly is detected, regardless of known exposure or symptoms (GRADE 1B); we suggest that magnetic resonance imaging be considered in cases of mild or moderate fetal ventriculomegaly when this modality and expert radiologic interpretation are available; magnetic resonance imaging is likely to be of less value if the patient has had a detailed ultrasound performed by an individual with specific experience and expertise in sonographic imaging of the fetal brain (GRADE 2B); we recommend that timing and mode of delivery be based on standard obstetric indications (GRADE 1C); we recommend that with isolated mild ventriculomegaly of 10-12 mm, after a complete evaluation, women be counseled that the outcome is favorable, and the infant is likely to be normal (GRADE 1B); we recommend that with isolated moderate ventriculomegaly of 13-15 mm, after a complete evaluation, women be counseled that the outcome is likely to be favorable but that there is an increased risk of neurodevelopmental disabilities (GRADE 1B).

Fetal ventriculomegaly: Diagnosis, treatment, and future directions

Fetal ventriculomegaly (VM) refers to the enlargement of the cerebral ventricles in utero. It is associated with the postnatal diagnosis of hydrocephalus. VM is clinically diagnosed on ultrasound and is defined as an atrial diameter greater than 10 mm. Because of the anatomic detailed seen with advanced imaging, VM is often further characterized by fetal magnetic resonance imaging (MRI). Fetal VM is a heterogeneous condition with various etiologies and a wide range of neurodevelopmental outcomes. These outcomes are heavily dependent on the presence or absence of associated anomalies and the direct cause of the ventriculomegaly rather than on the absolute degree of VM. In this review article, we discuss diagnosis, work-up, counseling, and management strategies as they relate to fetal VM. We then describe imaging-based research efforts aimed at using prenatal data to predict postnatal outcome. Finally, we review the early experience with fetal therapy such as in utero shunting, as well as the advances in prenatal diagnosis and fetal surgery that may begin to address the limitations of previous therapeutic efforts.

Fetal MRI of the central nervous system: State-of-the-art

Prenatal ultrasonographic (US) examination is considered as the first tool in the assessment of fetal abnormalities. However, several large-scale studies point out that some malformations, in particular central nervous system (CNS) anomalies, are not well characterized through US. Therefore, the actual malformation severity is not always related to prenatal ultrasound (US) findings. Over the past 20 years, ultrafast Magnetic Resonance Imaging (MRI) has progressively increased as a prenatal 3rd level diagnostic technique with a good sensitivity, particularly for the study of fetal CNS malformations. In fact, CNS anomalies are the most common clinical indications for fetal MRI, representing about 80% of the total examinations. This review covers the recent literature on fetal brain MRI, with emphasis on techniques, safety and indications.

Brain Injury in Neonates with Complex Congenital Heart Disease: What Is the Predictive Value of MRI in the Fetal Period?

BACKGROUND AND PURPOSE

Brain injury in neonates with congenital heart disease is an important predictor of adverse neurodevelopmental outcome. Impaired brain development in congenital heart disease may have a prenatal origin, but the sensitivity and specificity of fetal brain MR imaging for predicting neonatal brain lesions are currently unknown. We sought to determine the value of conventional fetal MR imaging for predicting abnormal findings on neonatal preoperative MR imaging in neonates with complex congenital heart disease.

MATERIALS AND METHODS

MR imaging studies were performed in 103 fetuses with confirmed congenital heart disease (mean gestational age, 31.57 ± 3.86 weeks) and were repeated postnatally before cardiac surgery (mean age, 6.8 ± 12.2 days). Each MR imaging study was read by a pediatric neuroradiologist.

RESULTS

Brain abnormalities were detected in 17/103 (16%) fetuses by fetal MR imaging and in 33/103 (32%) neonates by neonatal MR imaging. Only 9/33 studies with abnormal neonatal findings were preceded by abnormal findings on fetal MR imaging. The sensitivity and specificity of conventional fetal brain MR imaging for predicting neonatal brain abnormalities were 27% and 89%, respectively.

CONCLUSIONS

Brain abnormalities detected by in utero MR imaging in fetuses with congenital heart disease are associated with higher risk of postnatal preoperative brain injury. However, a substantial proportion of anomalies on postnatal MR imaging were not present on fetal MR imaging; this result is likely due to the limitations of conventional fetal MR imaging and the emergence of new lesions that occurred after the fetal studies. Postnatal brain MR imaging studies are needed to confirm the presence of injury before open heart surgery.

Fetal ventriculomegaly: Pregnancy outcomes and follow-ups in ten years

The aim of this study is to evaluate the pregnancy outcomes and prognoses for fetuses with ventriculomegaly. Two hundred and forty-one cases of fetuses with ventriculomegaly were included in this study. The subjects were divided into three groups according to their lateral ventricular width: "Mild Ventriculomegaly" (10 ‒ < 12 mm), "Moderate Ventriculomegaly" (12 ‒ < 15 mm) and "Severe Ventriculomegaly" (≥ 15 mm). Pediatric examination records and telephone interviews were conducted to track the outcomes of children until the age of 9 years. Eight-two cases were Isolated Ventriculomegaly (34.0%), while Non-Isolated Ventriculomegaly was found in 159 cases (66.0%). The pregnancy was terminated in 91 cases, and a higher abortion ratio was found in the NIVM (Non-Isolated Ventriculomegaly) group compared with the IVM (Isolated Ventriculomegaly) group. The fetuses were delivered in 150 cases, and four infants suffered deaths with NIVM. Of the surviving fetuses, 7 with IVM and 9 with NIVM showed significant abnormalities. The Mild and Moderate VM groups had more favorable prognoses compared with the Severe VM group. Regarding the outcomes and progression of lateral ventricular width, 1 out of 42 cases in the regressed group and 19 out of 108 cases in the stable group showed significant abnormalities. This study suggests that the degree and the progression of ventricular dilatation are main factors that affect pregnancy outcomes and prognoses.

Added value of fetal MRI in fetuses with suspected brain abnormalities on neurosonography: a systematic review and meta-analysis

PURPOSE

To evaluate the additional diagnostic value of fetal Magnetic Resonance Imaging (MRI) in fetuses with suspected brain abnormalities identified with advanced neurosonography (NS).

METHODS

A systematic literature search was performed for studies reporting on a comparison between diagnosis with NS and MRI, in fetuses suspected for brain abnormalities. Abnormalities detected on NS were compared with those detected on MRI as well as with postnatal imaging findings to assess the added value of fetal MRI.

RESULTS

We included 27 articles, reporting on 1184 cases in which NS and MRI diagnosis were compared. In 65% of cases [773/1184] fetal NS and fetal MRI diagnosis agreed completely. In 23% [312/1184], MRI showed additional or different pathology. In 8% [99/1184], MRI rejected the NS diagnosis with normal brain as conclusion. For 454 cases a comparison with postnatal imaging could be made. Compared to the postnatal diagnosis, fetal MRI diagnosis agreed completely in 80% [364/454] and fetal NS in 54% [243/454] (difference 27%, 95% CI 21-33%). Additional abnormalities were found on postnatal imaging in 36% [164/454] after NS and in 14% [61/454] after fetal MRI.

CONCLUSIONS

This meta-analysis shows that fetal MRI in addition to NS improves diagnostic accuracy in detecting brain abnormalities.

Isolated ventriculomegaly on prenatal ultrasound: what does fetal MRI add?

INTRODUCTION

Cerebral ventriculomegaly is one of the most commonly detected fetal anomalies at the midtrimester ultrasound. Current evidence suggests that magnetic resonance imaging (MRI) is indicated when the isolated ventriculomegaly (IVM) on ultrasound is severe (>15 mm), but there is less agreement when IVM is mild or moderate (10-15 mm). The current study aimed to determine the frequency and nature of additional findings on MRI in IVM and their relationship to the severity of VM and gestational age.

METHODS

Data were gathered prospectively from all pregnant women with ultrasound-diagnosed IVM referred for MRI between November 2006 and February 2013. Cases with IVM and no other suspected cranial abnormality on a tertiary ultrasound performed at our institution, at or after 20 weeks gestation, were included.

RESULTS

Of the 59 fetuses with unilateral or bilateral IVM, additional findings were seen on MRI in 10 cases (17%) and half of these findings were identified in fetuses with mild IVM. Five of 40 (12.5%) fetuses with mild IVM had additional findings and 3/5 (60%) were potentially clinically significant. No additional abnormalities were identified in fetuses less than or equal to 24 weeks gestation with mild or moderate IVM. There was no statistically significant relationship between gestational age and additional findings on MRI in mild IVM. Callosal and septum pellucidum lesions, periventricular abnormalities and malformations of cortical development accounted for all of the significant additional findings.

CONCLUSION

This study helps to inform referral of pregnant women with a fetus who has IVM for prenatal MRI.

Neurodevelopmental outcome in isolated mild fetal ventriculomegaly: systematic review and meta-analysis

OBJECTIVES

The finding of fetal ventriculomegaly is variably associated with other fetal abnormalities and, even when isolated, is thought to be linked to abnormal neurodevelopmental outcome. The aim of this study was to undertake a systematic review and meta-analysis of the current literature to assess the prevalence of neurodevelopmental delay in cases of isolated mild fetal ventriculomegaly, as well as the false-negative rate of prenatal imaging for the diagnosis of associated abnormalities in patients referred for isolated mild ventriculomegaly.

METHODS

Studies that assessed neurodevelopmental outcome in isolated ventriculomegaly were identified from a search of scientific databases. Studies that did not check for karyotype or that excluded cases of bilateral ventriculomegaly were not included in the analysis. Ventriculomegaly was defined as mild when the width of the ventricular atrium was between 10 and 15 mm. Cases in which an associated abnormality (abnormal karyotype, structural abnormality or fetal infection) was observed either before or after birth were not considered as part of the isolated group. Neurodevelopmental delay was defined as an abnormal quotient score, according to the test used.

RESULTS

The search yielded 961 possible citations; of these, 904 were excluded by review of the title or abstract as they did not meet the selection criteria. Full manuscripts were retrieved for 57 studies, and 20 were included in the review with a total of 699 cases of isolated mild ventriculomegaly. The overall prevalence of neurodevelopmental delay was 7.9% (95% CI, 4.7-11.1%). Of the 20 studies included in the systematic review, nine reported data on postnatal imaging, showing a prevalence of previously undiagnosed findings of 7.4% (95% CI, 3.1-11.8%).

CONCLUSIONS

The false-negative rate of prenatal imaging is 7.4% in apparently isolated fetal ventriculomegaly of ≤ 15 mm. The incidence of neurodevelopmental delay in truly isolated ventriculomegaly of ≤ 15 mm is 7.9%. As the latter rate is similar to that noted in the general population, large prospective cohort studies assessing the prevalence of childhood disability, rather than subtle neurodevelopmental delay, are required.

The fundamentals of fetal MR imaging: Part 1

Congenital malformations detected in any fetal system using ultrasound may be further evaluated with magnetic resonance imaging (MRI) to improve counseling, to plan deliveries appropriately, and sometimes to enable fetal interventions. In this first half of a 2-part review, the history and safety factors regarding fetal MRI, as well as the practical aspects of image acquisition, are discussed. In addition, as central nervous system anomalies are most commonly and best evaluated using fetal MRI, challenging central nervous system anomalies, such as fetal ventriculomegaly, posterior anomalies, and neural tube defects, detected using prenatal ultrasound are also reviewed with a focus on the fundamental implications of these diagnoses.

Postnatal outcome of isolated, nonprogressive, mild borderline fetal ventriculomegaly

BACKGROUND

This study aimed to evaluate postnatal outcome of fetuses affected by nonprogressive, isolated, mild (≥10 and ≤12 mm) borderline ventriculomegaly (BVM).

METHODS

We studied 25 consecutive fetuses with BMV and evaluated patients' characteristic, ultrasonographic findings, and the neurodevelopmental outcome at age ≥24 months.

RESULTS

The mean gestational age at diagnosis was 23.84 ± 5.02 weeks (min-max; 17-34 weeks). In 16 cases, BVM was bilateral (16/25, 64 %), 4 left sided (4/25, 16 %), and 5 right sided (5/25, 20 %). Fourteen cases were males (14/25, 56 %), and 11 cases were females (11/25, 44 %). In two cases, ventriculomegaly was regressed 4 weeks after the initial diagnosis (2/25, 8 %), and in the remaining cases, ventriculomegaly persisted between initial measurement and 12 mm. The mean age of the infant at the time of the neurodevelopmental evaluation was 45.9 months (24-77 months). The neurodevelopmental outcome at the mean age of 45.9 months was completely normal in 16 infants (16/25, 64 %). The remaining nine infants (9/25, 36 %) had mild degree of neuromotor developmental delay.

CONCLUSION

Prenatal counseling for isolated, nonprogressive, mild BVM should be mainly reassurance since it is not associated with severe neurodevelopmental delay. However, parents should be educated about the developmental milestone of children to observe and detect mild neurodevelopmental delay which can be associated with mild BVM.