Prenatal isolated mild ventriculomegaly: outcome in 167 cases

Evolution of fetal ventricular dilatation in relation to severity at first presentation

BACKGROUND

To assess the outcome of 360 cases of fetal ventriculomegaly in a tertiary referral center.

METHODS

Cases of fetal ventriculomegaly between June 1993 and December 2011 were identified from the departmental fetal database. The fetal medicine reports and obstetric notes were reviewed to ascertain the antenatal progression of the ventriculomegaly as well as the outcome of the pregnancy. Ventriculomegaly was defined by a lateral ventricular wall atrial measurement of greater than 10 mm. Cases were subdivided into mild (>10 to <12 mm), moderate (≥12 to <15 mm), and severe (≥15 mm). Termination of pregnancy was offered in cases where there were associated anomalies, aneuploidy, or the ventriculomegaly progressed.

RESULTS

Of the 360 cases, 189 were mild, 79 were moderate, and 92 were severe. Sixty-four percent of cases had associated anomalies. Forty-six percent of cases in the mild group and 26% in the moderate group resolved. Only one case in the severe group improved. The mean rate of progression in the mild group was 1.07 (SD 1.03) mm/week, whereas in the moderate group progression was at a mean rate of 1.41 (SD 0.77) mm/week. Progression of severe ventriculomegaly was significantly higher at a mean rate of 3.26 (SD 2.92) mm/week (p = 0.007).

CONCLUSIONS

The majority of fetuses with mild ventriculomegaly normalized, whereas the majority of moderate cases remained stable. The rate of progression of ventriculomegaly increased with severity. Fetuses with ventriculomegaly should be offered serial scans to allow the progression of ventriculomegaly to be ascertained with the option of late termination of pregnancy.

Perinatal characteristics of fetuses with borderline ventriculomegaly detected by routine ultrasonographic screening of low-risk populations

AIM

Fetal borderline ventriculomegaly represents a frequent dilemma in perinatal management. The present study aimed to evaluate the clinical significance of fetal borderline ventriculomegaly in a low-risk Japanese population and to identify the risk factors for associated anomalies.

METHODS

Data of cases of fetal borderline ventriculomegaly detected at 26-28 weeks of gestation by routine ultrasonographic screening of low-risk singleton pregnancies between 2006 and 2012 were retrospectively collected. Ventricular width, in utero progression, associated anomalies, chromosomal abnormalities, and perinatal and postnatal outcomes were assessed. The ventricular width, in utero progression and other perinatal characteristics were compared between the isolated and non-isolated groups.

RESULTS

Among the total 6020 singleton low-risk pregnancies, we noted that 42 had borderline ventriculomegaly. Six (14%) of these cases had other defects by subsequent detailed examination. Ventriculomegaly resolved or regressed in 35 (83%) and progressed in four (10%) cases, of which three were associated with other anomalies. The median ventricular width was 12.8 mm (range, 10.0-14.7) in the six non-isolated cases and 10.5 mm (range, 10.0-13.3) in the 36 isolated cases; the differences were statistically significant. A ventricular width of 12 mm or more and in utero progression were more frequently observed in non-isolated cases than in isolated cases.

CONCLUSION

Fetal borderline ventriculomegaly frequently resolves in utero. A ventricular diameter of more than 12 mm and in utero progression are risk factors for additional anomalies. After the initial diagnosis of borderline ventriculomegaly, the pregnancy should be carefully followed up to determine whether the ventricle size is resolved, remains stable or increases.

Coronal approach for measuring both fetal lateral ventricles: is there an advantage over the axial view?

OBJECTIVE

This study aimed to compare measurement of the lateral cerebral ventricular diameter using either the traditional axial view or the coronal plane.

MATERIALS AND METHODS

We performed a prospective study on 144 fetuses, 77 evaluated as part of a routine fetal scan and 67 referred for a neurosonogram. Distal lateral ventricles were measured both in axial and coronal plane.

RESULTS

Good visualization of the ventricles was achieved in 91% of the cases using the coronal plane (both ventricles) and in 95% of the cases using the axial plane (only the distal ventricle) (p > 0.001). The mean width of the distal lateral ventricle in the axial plane was 7.9 ± 1.9 mm versus 8.2 ± 1.9 mm on the coronal plane (p < 0.001). This larger diameter by 0.3 mm was not dependent on the indication for the scan or the gestational age. Slight asymmetry was present on coronal images in the routine group (0.2 mm), and that was even larger in the referral group (1.6 mm) (p < 0.001).

CONCLUSION

Coronal measurement of both ventricles is feasible and has the advantage over measurement in the axial view in which only the distal ventricle is clearly visible and measurable.

Clinical outcomes of mild isolated cerebral ventriculomegaly in the presence of other neurodevelopmental risk factors

OBJECTIVES

The purpose of this study was to evaluate neuropsychological test data in school-aged children whose fetal sonograms revealed mild isolated cerebral ventriculomegaly without asymmetry of the lateral ventricles.

METHODS

Nine of 52 children 6 years and older with sonographic evidence of mild isolated cerebral ventriculomegaly without asymmetry of the lateral ventricles were able to be recruited for follow-up school-aged neuropsychological testing. The children received a half-day battery of neuropsychological tests, including the Wechsler Abbreviated Scales of Intelligence; Beery-Buktenica Developmental Test of Visual Motor Integration, Fifth Edition; Wide Range Achievement Test, Fourth Edition; and Integrated Visual and Auditory Continuous Performance Test. Parents completed the Conners 3 Parent Short Form and the Personality Inventory for Children, Second Edition.

RESULTS

In this small group, other risk factors for neurodevelopmental disorders were often present, including preterm birth, perinatal hypoxia, and a family history of psychiatric disease or substance abuse. Within this sample, the proportion of children with a pattern of test results showing poorer nonverbal intelligence than verbal intelligence scores and poorer math than reading performance, as well as meeting criteria for a diagnosis of attention deficit/hyperactivity disorder, was higher than the basal rates of these problems among children in general.

CONCLUSIONS

Particularly given the complexity of various factors affecting neurodevelopment, follow-up neuropsychological evaluation is warranted in children with sonographic evidence of mild isolated cerebral ventriculomegaly without asymmetry of the lateral ventricle (eg, in the context of poor school performance).

Post-mortem apparent resolution of fetal ventriculomegaly: evidence from magnetic resonance imaging

OBJECTIVE

This study aims to determine the accuracy of post-mortem magnetic resonance imaging (MRI) and autopsy for confirmation of sonographically detected fetal ventriculomegaly.

METHODS

This study uses retrospective review of fetuses with sonographically diagnosed ventriculomegaly, where the pregnancy was terminated and post-mortem examination was performed during a period in which post-mortem MRI was being offered.

RESULTS

Sixteen cases were identified. In nine (56%), autopsy and/or post-mortem MRI confirmed the prenatal findings. In the other seven, both autopsy and post-mortem MRI demonstrated no ventriculomegaly, but antenatal MRI confirmed the ultrasound findings in 6/7 cases where it had been performed. Post-mortem investigations confirmed antenatal findings in 8/9 cases with severe ventriculomegaly (posterior horn measurement >15 mm), whereas only 2/7 in which ventriculomegaly was not confirmed had severe ventriculomegaly.

CONCLUSIONS

Post-mortem examination, both by traditional neuropathological examination, and post-mortem MRI may fail to confirm prenatal ventriculomegaly in around half of cases. The post-mortem MRI findings indicate that this is due to resolution of ventriculomegaly rather than autopsy artefact, and is presumably a consequence of post-mortem fluid redistribution. Parents should be advised before termination of pregnancy that post-mortem confirmation of ventriculomegaly, especially in mild cases, may not be possible. Antenatal MRI may be a better approach for confirming prenatal ultrasound findings.

Neuroimaging of ventriculomegaly in the fetal period

Fetal cerebral ventriculomegaly (VM) is defined as an enlargement of the lateral ventricles of the developing fetal brain. It is diagnosed when the width of one or both lateral ventricles, measured at the level of the atrium, is ≥10 mm. VM is defined as mild when the atrial width is 10-15 mm and severe when >15 mm. VM is a non-specific sonographic sign which is common to various pathological conditions. It is frequently associated with neural and extraneural anomalies. The rate of associated malformations is higher (≥60%) in severe VM and lower (about 40%) in cases of mild VM. When an abnormality is associated with severe VM the incidence of aneuploidies is high (>15%); in isolated mild VM the mean value of aneuploidy is 2.7%. The rate of infections in severe VM is 10-20%, in mild forms 1-5%. Since the prognosis in cases of VM depends mainly on the associated anomalies, a careful examination of the fetus, particularly of the brain, is mandatory. Magnetic resonance imaging can be a useful diagnostic tool complementary to ultrasound in order to recognize subtle brain anomalies, such as neuronal migration and proliferation disorders.

Cortical maturation in fetuses referred for 'isolated' mild ventriculomegaly: a longitudinal ultrasound assessment

OBJECTIVES

To compare cortical maturation between fetuses with isolated mild ventriculomegaly (IMV) and healthy fetuses, and to explore its potential prognostic value in IMV.

METHODS

This prospective study quantified cortical maturation by ultrasound in 24 fetuses with IMV and 46 healthy fetuses. Depth and grading the developmental pattern of the parieto-occipital fissure (POF), calcarine fissure (CF) and sylvian fissure, and grading the Sylvian fissure operculization at 23-25, 27-28 and 31-32 weeks gestation were determined.

RESULTS

At 23-25 and 27-28 gestational weeks, POF and CF mean depths were statistically lower in the IMV group. The POF and CF depth distribution had a normal distribution in the control group but displayed a bimodal distribution in the IMV group. IMV with progression of ventricular dilatation showed mean depth of CF lower than IMV in which ventriculomegaly regressed or remained stable. The sensitivity, specificity, positive predictive value and negative predictive value of a CF depth below the fifth percentile to predict progression of ventricular dilatation were, at 28 weeks, 100%, 88%, 67% and 100%, respectively.

CONCLUSIONS

Cortical fissure assessment by ultrasound allowed the differentiation of a subgroup of IMV fetuses with a higher risk of progression of ventricular dilatation.

Prenatal isolated mild ventriculomegaly is associated with persistent ventricle enlargement at ages 1 and 2

BACKGROUND

Enlargement of the lateral ventricles is thought to originate from abnormal prenatal brain development and is associated with neurodevelopmental disorders. Fetal isolated mild ventriculomegaly (MVM) is associated with the enlargement of lateral ventricle volumes in the neonatal period and developmental delays in early childhood. However, little is known about postnatal brain development in these children.

METHODS

Twenty-eight children with fetal isolated MVM and 56 matched controls were followed at ages 1 and 2 years with structural imaging on a 3T Siemens scanner and assessment of cognitive development with the Mullen Scales of Early Learning. Lateral ventricle, total gray and white matter volumes, and Mullen cognitive composite scores and subscale scores were compared between groups.

RESULTS

Compared to controls, children with prenatal isolated MVM had significantly larger lateral ventricle volumes at ages 1 and 2 years. Lateral ventricle volume at 1 and 2 years of age was significantly correlated with prenatal ventricle size. Enlargement of the lateral ventricles was associated with increased intracranial volumes and increased gray and white matter volumes. Children with MVM had Mullen composite scores similar to controls, although there was evidence of delay in fine motor and expressive language skills.

CONCLUSIONS

Children with prenatal MVM have persistent enlargement of the lateral ventricles through the age of 2 years; this enlargement is associated with increased gray and white matter volumes and some evidence of delay in fine motor and expressive language development. Further study is needed to determine if enlarged lateral ventricles are associated with increased risk for neurodevelopmental disorders.

Prenatal-postnatal correlations of brain abnormalities: how lesions and diagnoses change over time

A combination of prenatal ultrasound and MRI can be used to detect and characterize many primary and secondary CNS abnormalities in the developing fetus. While this information is useful in prenatal patient counseling, it is important to understand the factors that can influence change in diagnosis and prognosis over time. The etiology of the abnormality, the conspicuity of associated findings, the change in appearance over time, and the opinion of subspecialty experts all can influence the diagnosis. Additionally, technical factors of imaging acquisition may allow the detection of an abnormality in the postnatal period and not prenatally. Having an understanding of the normal fetal central nervous system anatomy at varying gestational ages will aid in the imaging detection and interpretation of CNS pathology. Understanding how these appearances and diagnoses can change over time will aid in the discussion of prognosis with expectant parents, which is crucial in fetal CNS abnormalities.

Prenatal neurologic anomalies: sonographic diagnosis and treatment

The low prevalence of fetal CNS anomalies results in a restricted level of exposure to, and limited experience for most obstetricians involved in, prenatal ultrasound. Sonographic guidelines for screening the fetal brain in a systematic way may increase the detection rate of fetal CNS anomalies, thus promoting correct referral to tertiary care centers offering patients a multidisciplinary approach to the condition. The aim of this review is to elaborate on the prenatal sonographic diagnosis and outcome of various CNS malformations. Detailed neurosonographic investigation has become available through high-resolution vaginal ultrasound probes and the development of a variety of 3-dimensional (3D) ultrasound modalities, such as ultrasound tomographic imaging. In addition, fetal magnetic resonance imaging is particularly helpful in the detection of gyration and neurulation anomalies, and disorders of the gray and white matter. Isolated mild ventriculomegaly is a rather common finding with good overall outcome. With an increasing diameter of the atria, however, and especially with the presence of associated malformations, long-term neurodevelopmental and behavioral outcome is disturbed in about 15% or more of cases. In view of recent developments in fetal therapy for neural tube defects, there is a clear need for a high level of ultrasound screening, work-up and counseling in tertiary care centers to identify those cases that might benefit from in utero intervention. The failure of prosencephalic midline induction and development results in midline defects ranging from alobar holoprosencephaly to isolated corpus callosum defects. The detection of callosal abnormaties is enhanced by 3D ultrasound, but counseling on neurodevelopmental outcome remains challenging. The Dandy-Walker spectrum includes isolated megacisterna magna, Blake's pouch cyst, hypoplasia of the vermis and Dandy-Walker malformation. Except for complete agenesis of the vermis associated with fourth ventricle cyst formation, data on long-term outcomes for the various conditions is largely lacking. Congenital cytomegalovirus (CMV) results in the highest incidence of children born with, or developing, long-term neurologic conditions. If proof of fetal infection has been delivered, microcephaly, cortical malformations, and intraparenchymal cysts show a strong correlation with poor outcome. Fetuses with CMV-related ultrasound abnormalities might benefit from maternal transplacental treatment. The aneurysm of the vein of Galen, a vascular malformation of the brain, often results in high cardiac output failure. After neonatal arterial embolization, survival is about 50% with normal neurologic development in 36% of cases. Over 50% of intracranial tumors are teratomata, presenting as fast-growing heterogeneous solid-cystic masses with calcifications. Most intracranial hemorrhages are related to the ventricular system, and prognosis is often poor, particularly in cases involving parenchymal and subdural bleeding. Proliferation disorders of the brain are often characterized by microcephaly. Their etiology is heterogeneous and prenatal diagnosis is often made late in gestation.

Volumetric and surface-based 3D MRI analyses of fetal isolated mild ventriculomegaly: brain morphometry in ventriculomegaly

Diagnosis of fetal isolated mild ventriculomegaly (IMVM) is the most common brain abnormality on prenatal ultrasound. We have set to identify potential alterations in brain development specific to IMVM in tissue volume and cortical and ventricular local surface curvature derived from in utero magnetic resonance imaging (MRI). Multislice 2D T2-weighted MRI were acquired from 32 fetuses (16 IMVM, 16 controls) between 22 and 25.5 gestational weeks. The images were motion-corrected and reconstructed into 3D volumes for volumetric and curvature analyses. The brain images were automatically segmented into cortical plate, cerebral mantle, deep gray nuclei, and ventricles. Volumes were compared between IMVM and control subjects. Surfaces were extracted from the segmentations for local mean surface curvature measurement on the inner cortical plate and the ventricles. Linear models were estimated for age-related and ventricular volume-associated changes in local curvature in both the inner cortical plate and ventricles. While ventricular volume was enlarged in IMVM, all other tissue volumes were not different from the control group. Ventricles increased in curvature with age along the atrium and anterior body. Increasing ventricular volume was associated with reduced curvature over most of the ventricular surface. The cortical plate changed in curvature with age at multiple sites of primary sulcal formation. Reduced cortical folding was detected near the parieto-occipital sulcus in IMVM subjects. While tissue volume appears to be preserved in brains with IMVM, cortical folding may be affected in regions where ventricles are dilated.

Early prenatal ventriculomegaly due to an AIFM1 mutation identified by linkage analysis and whole exome sequencing

The identification of disease causing mutation in patients with neurodegenerative disorders originating from small, non-consanguineous families is challenging. Three siblings were found to have ventriculomegaly at early gestation; postnatally, there was no acquisition of developmental milestones, and the muscles of the children were dystrophic. Plasma and CSF lactate levels were normal, but the activities of mitochondrial complex I and IV were markedly decreased. Using linkage analysis in the family, followed by whole exome sequencing of a single patient, we identified a pathogenic mutation in the AIFM1 gene which segregated with the disease state and was absent in 86 anonymous controls. This is the second report of a mutation in the AIFM1 gene, extending the clinical spectrum to include prenatal ventriculomegaly and underscores the importance of AIF for complex I assembly. In summary, linkage analysis followed by exome sequencing of a single patient is a cost-effective approach for the identification of disease causing mutations in small non-consanguineous families.

Magnetic resonance volumetric assessments of brains in fetuses with ventriculomegaly correlated to outcomes

OBJECTIVES

The purpose of this study was to correlate 2-dimensional magnetic resonance (MR) measurements of lateral ventricular width and 3-dimensional measurements of lateral ventricular and supratentorial parenchymal volumes to postnatal outcomes in fetuses with ventriculomegaly.

METHODS

A total of 307 fetuses (mean gestational age, 26.0 weeks; range, 15.7-39.4 weeks) had MR volumetry after referral for ventriculomegaly. Fetuses were grouped into those with (n = 114) and without (n = 193) other central nervous system (CNS) anomalies. Pregnancy and postnatal neurodevelopmental outcomes up to 3 years of age were obtained. A subgroup analysis was performed excluding fetuses with other CNS anomalies. Logistic regression analysis was performed to assess which measurement was most predictive of outcomes.

RESULTS

There were 50 terminations, 2 stillbirths, and 255 live births. Seventy-five cases were lost to follow-up. Among 180 live-born neonates with follow-up, 140 had abnormal and 40 had normal outcomes. Atrial diameter (P < .0001), frontal horn diameter (P < .0001), and ventricular volume (P = .04) were predictive of live birth, with 92% specificity at 60% sensitivity. Among fetuses without other CNS anomalies, 180 of 193 pregnancies (93%) resulted in live deliveries, with atrial diameter (P < .0001), frontal horn diameter (P = .003), and ventricular volume (P = .008) associated with live birth and atrial diameter having the highest specificity (>99% at 60% sensitivity). Parenchymal volume was not associated with normal or abnormal outcomes (either live birth versus death or normal versus abnormal neurodevelopmental outcome). Among live-born neonates, no age-adjusted threshold for any of the measurements reliably distinguished between normal and abnormal neurodevelopmental outcomes.

CONCLUSIONS

Ventricular volume and diameter, but not parenchymal volume, correlate with live birth in fetuses with ventriculomegaly. However, once live born, neither 2- nor 3-dimensional measurements can distinguish a fetus that will have a normal outcome.

Frequency and cause of disagreements in imaging diagnosis in children with ventriculomegaly diagnosed prenatally

OBJECTIVES

To assess the frequency and cause of variability in diagnosis on cranial sonography and magnetic resonance imaging (MRI) in children referred following prenatal diagnosis of ventriculomegaly.

METHODS

Between 19 September 2003 and 16 March 2007, 119 infants with ultrasound and/or MRI studies performed within 13 months (median, 6 days) after birth, following prenatal referral for ventriculomegaly, were studied prospectively. There were 97 infants with ultrasound results and 53 with MRI, including 31 with both. Three sonologists and three pediatric neuroradiologists interpreted the postnatal ultrasound and MRI findings, blinded to prenatal diagnosis, and a final consensus diagnosis or group of diagnoses was obtained. Ventricular sizes as well as types of and reasons for any disagreement in diagnosis were recorded. Disagreements on a per patient basis were categorized as being major when they crossed diagnostic categories and had the potential to change patient counseling. Postnatal and prenatal diagnoses were compared.

RESULTS

There was prospective agreement on 42/97 (43%) ultrasound and on 9/53 (17%) MRI readings. Prospective consensus was more likely when the number of central nervous system (CNS) anomalies was lower (P < 0.001 and P = 0.002 for ultrasound and MRI, respectively). In 24/55 (44%) ultrasound and 11/44 (25%) MRI examinations with disagreement in diagnosis, there was disagreement concerning the presence of ventriculomegaly. In 22/97 (23%) ultrasound studies and 22/53 (42%) MRI studies the disagreements were potentially important. Reasons for discrepancies in the reporting of major findings included errors of observation as well as modality differences in depiction of abnormalities. In comparing prenatal with postnatal diagnoses, there were 11/97 (11%) ultrasound and 27/53 (51%) MRI examinations with newly detected major findings, the most common being migrational abnormalities, callosal dysgenesis/destruction and interval development of hemorrhage.

CONCLUSION

Variability in postnatal CNS diagnosis is common after a prenatal diagnosis of ventriculomegaly. This is due in part to a lack of standardization in the definition of postnatal ventriculomegaly.

Magnetic resonance imaging versus ultrasonography for the in utero evaluation of central nervous system anomalies

OBJECT

The use of fetal MR imaging for the in utero evaluation of pathological conditions of the CNS is widely accepted as an adjunct to fetal ultrasonography studies. Magnetic resonance imaging is thought to characterize CNS anomalies better, and to provide a more exact diagnosis and accurate prognosis. The purpose of this study was to determine the role of and indications for fetal MR imaging in evaluating fetuses with different CNS abnormalities that were seen initially on prenatal sonograms.

METHODS

Over a 3-year period, fetuses with prior sonographic evidence of CNS abnormalities who consequently received prenatal MR imaging at Columbus Nationwide Children's Hospital within 2 weeks of the fetal ultrasonography study were included in this study. For each patient, radiological reports from both studies were reviewed, analyzed, and compared with the findings at postnatal imaging or physical examination. Results of the 2 modalities were then compared in terms of diagnostic accuracy.

RESULTS

Twenty-six fetuses were included in this study on the basis of an in utero sonogram showing a CNS anomaly. Their gestational age ranged from 17 to 35 weeks, with a mean of 25 weeks at the time of fetal ultrasonography. Hydrocephalus was identified in 16 fetuses, 6 had evidence of a spinal dysraphic defect, 2 had holoprosencephaly, 1 had an encephalocele, and 1 had multiple body abnormalities requiring detailed CNS evaluation. Twenty-five of the fetuses were correctly evaluated as having abnormal CNS findings on both fetal ultrasonography and fetal MR imaging. Fetal ultrasonography provided a correct prenatal diagnosis in 20 cases, whereas fetal MR imaging was correct in 22 cases. There were 9 cumulative false-positive results for fetal ultrasonography and 7 for fetal MR imaging, whereas for false-negative results there were a total of 34 and 19, respectively.

CONCLUSIONS

Fetal MR imaging is more sensitive in detecting fetal CNS abnormalities, but its ability to provide a correct prenatal diagnosis is only marginally superior to fetal ultrasonography. Moreover, fetal MR imaging is not exempt from misdiagnosis, and still shows a significantly high rate of false-negative results. Particularly for spinal dysraphic defects, fetal MR imaging does not seem to add important diagnostic or prognostic details when compared with fetal ultrasonography.

Prognosis of isolated mild to moderate fetal cerebral ventriculomegaly: a systematic review

AIMS

To ascertain risk of aneuploidy, infection and neurological abnormality for the fetus diagnosed with isolated mild (10.1-12.0 mm) to moderate (12.1-15.0 mm) cerebral ventriculomegaly and to compare the neurological outcome between symmetrical vs. asymmetrical and stable vs. progressive ventriculomegaly.

METHODS

A systematic review was conducted. Literature was identified by searching two bibliographical databases between 1980 and 2009 without language restrictions. The data extracted were inspected for heterogeneity. Overall rates and confidence intervals (CIs) for each prognostic factor were calculated. When comparative data existed, the odds ratio (OR) was calculated.

RESULTS

The search strategy yielded 2150 relevant citations of which 28 studies were included in the review. The overall rate of infection and chromosomal abnormality was 1.5 and 5% (95% CI 3, 7), respectively. The risk of neurological abnormality regardless of karyotype or infection screen was 14% (95% CI 10, 18) and this reduced to 12% (95% CI 9, 15) when both chromosomes and infection screen were normal. The risk of neurological abnormality was significantly lower in stable compared to progressive ventriculomegaly [OR 0.29 (95% CI 0.15, 0.58)]. No significant differences were detected when symmetrical vs. asymmetrical ventriculomegaly were compared [OR 0.91 (95% CI 0.34, 2.41)].

CONCLUSION

This systematic review provides the physician with some estimates of prognosis in cases of isolated mild to moderate ventriculomegaly.

Neurodevelopmental outcome of fetuses referred for ventriculomegaly

OBJECTIVE

To characterize the delivery and postnatal neurodevelopmental outcomes of fetuses referred for ventriculomegaly (VM).

METHODS

Under an internal review board-approved protocol, pregnant women were referred for magnetic resonance imaging (MRI) after sonographic diagnosis of VM and classified into one of four diagnostic groups: Group 1, normal central nervous system (CNS); Group 2, isolated mild VM (10-12 mm); Group 3, isolated VM > 12 mm; and Group 4, other CNS findings. Pregnancy outcome was obtained. Follow-up visits were offered with assessment of neurodevelopmental, adaptive and neurological functioning at 6 months and 1 year and/or 2 years of age. Atrial diameter and VM group differences in developmental outcomes were evaluated using repeated measures logistic regression and Fishers exact test, respectively.

RESULTS

Of 314 fetuses, 253 (81%) were liveborn and survived the neonatal period. Fetuses in Groups 4 and 3 were less likely to progress to live delivery and to survive the neonatal period (60% and 84%, respectively) than were those in Groups 2 or 1 (93% and 100%, respectively, P < 0.001). Of the 143 fetuses followed postnatally, between 41% and 61% had a Bayley Scales of Infant Development (BSID-II) psychomotor developmental index score in the delayed range (< 85) at the follow-up visits, whereas the BSID-II mental developmental index and Vineland Adaptive Behavior composite scores were generally in line with normative expectations. Among those that were liveborn, neither VM group nor prenatal atrial diameter was related to postnatal developmental outcome.

CONCLUSIONS

Diagnostic category and degree of fetal VM based on ultrasound and MRI measurements are associated with the incidence of live births and thus abnormal outcome. Among those undergoing formal postnatal testing, VM grade is not associated with postnatal developmental outcome, but motor functioning is more delayed than is cognitive or adaptive functioning.

A prospective study of fetuses with isolated ventriculomegaly investigated by antenatal sonography and in utero MR imaging

BACKGROUND AND PURPOSE

Fetal ventriculomegaly (VM) is important because of its high prevalence and high risk of association with other brain abnormalities. The purpose of this article was to investigate the hypotheses that including in utero MR imaging (iuMR) in the diagnostic pathway for fetuses with isolated VM on antenatal imaging will show other brain abnormalities in a high proportion of cases and that these will have a significant effect on clinical management.

MATERIALS AND METHODS

One hundred forty-seven pregnant women were recruited prospectively from 8 fetomaternal centers in Britain. All of the fetuses had VM diagnosed on sonography but no other abnormality. iuMR was performed, and the results of the examinations were compared with those of sonography. Two fetomaternal experts made independent assessments of the effects of any new diagnoses on clinical management.

RESULTS

Categoric assessments of ventricular size were the same in approximately 90% of fetuses. Other abnormalities were shown in 17% of fetuses. The most frequent additional brain abnormality shown on iuMR was agenesis of the corpus callosum. Severe VM was associated with an approximately 10-fold increase in the risk of another brain abnormality being present when compared with fetuses with mild VM. The most profound effects on clinical management, however, were found in cases of mild VM.

CONCLUSIONS

This work supports our hypotheses by showing a high detection rate of other brain pathology when iuMR was used to supplement antenatal sonography (17%). In a high proportion of cases, the detection of the extra pathology would have led to significant changes in clinical management.

The current state and future of fetal imaging

Fetal magnetic resonance imaging (MRI) may add important diagnostic information to prenatal sonography and has the power to confirm or change decisions at critical points in clinical care. Recent studies have shown MRI to be a critical clinical adjunct in the evaluation of the developing central nervous system (CNS), especially at early gestational ages, and MRI has been used in three significant ways: (1) for the quantification of brain growth and structural abnormalities using biometry, (2) for the qualitative evaluation of CNS microstructure, and (3) for the qualitative assessment of dynamic fetal movements in utero.

Counseling in isolated mild fetal ventriculomegaly

In this Review we aim to provide up-to-date and evidence-based answers to the common questions regarding the diagnosis of isolated mild fetal ventriculomegaly (VM). A literature search was performed to identify all reports of antenatal VM in the English language literature. In addition, reference lists of articles identified using the search were scrutinized to further identify relevant articles. Fetal mild VM is commonly defined as a ventricular atrial width of 10.0-15.0 mm, and it is considered isolated if there are no associated ultrasound abnormalities. There is no good evidence to suggest that the width of the ventricular atria contributes to the risk of neurodevelopmental outcome in fetuses with mild VM. The most important prognostic factors are the association with other abnormalities that escape early detection and the progression of ventricular dilatation, which are reported to occur in about 13% and 16% of cases, respectively. Most infants with a prenatal diagnosis of isolated mild VM have normal neurological development at least in infancy. The rate of abnormal or delayed neurodevelopment in infancy is about 11%, and it is unclear whether this is higher than in the general population. Furthermore, the number of infants that develop a real handicap is unknown. There are limitations of existing studies of mild VM. Although they address many of the relevant questions regarding the prognosis and management of fetal isolated mild VM, there is a lack of good-quality postnatal follow-up studies. The resulting uncertainties make antenatal counseling for this abnormality difficult.

The neurocognitive outcome of mild isolated fetal ventriculomegaly verified by prenatal magnetic resonance imaging

OBJECTIVE

Neurocognitive outcome of preschool children, prenatal diagnosis of isolated mild ventriculomegaly compared with 2 control groups.

STUDY DESIGN

Case-controlled study at the University Hospital of Tel Aviv between October 1999 and December 2002. Study groups consisted of 12 children with bilateral isolated mild ventriculomegaly, and 16 children with unilateral isolated mild ventriculomegaly, mean age 4.4 years, prenatally diagnosed by both ultrasound and fetal magnetic resonanace imaging. Control groups consisted of 16 children with normal prenatal magnetic resonance imaging and 16 regular kindergarten children. A neurodevelopmental examination and the Kaufman Assessment Battery for Children were performed.

RESULTS

The neurodevelopmental and Kaufman scores were within normal range in the study groups. No significant differences between the study and control groups for most measures; however, Kaufman achievement score was significantly lower for the bilateral isolated mild ventriculomegaly group (P < .05) compared with the kindergarten children.

CONCLUSION

Preschool children with isolated mild ventriculomegaly performed within normal range compared with the controls. Nevertheless, a significant percentage of the children demonstrated developmental difficulties, lower achievement scores, justifying early school years follow-up.

The significance of fetal ventriculomegaly: etiology, short- and long-term outcomes

Fetal cerebral ventriculomegaly (VM) is diagnosed when the width of one or both ventricles, measured at the level of the glomus of the choroid plexus (atrium), is > or = 10 mm. VM can result from different processes: abnormal turnover of the cerebrospinal fluid (CSF), neuronal migration disorders, and destructive processes. In a high percentage of cases, it is associated with structural malformations of the central nervous system (CNS), but also of other organs and systems. The rate of associated malformations is higher (> or =60%) in severe VM (>15 mm) and lower (10-50%) in cases of borderline VM (10-15 mm). When malformations are not present, aneuploidies are found in 3-15% of borderline VM; the percentage is lower in severe VM. The neurodevelopmental outcome of isolated VM is normal in > 90% of cases if the measurement of ventricular width is between 10 and 12 mm; it is less favorable when the measurement is > 12 mm.

Correlation between ventriculomegaly on prenatal magnetic resonance imaging and the need for postnatal ventricular shunt placement

OBJECT

Pediatric neurosurgeons are increasingly called on to provide prognostic data regarding the antenatal diagnosis of ventriculomegaly. This study was designed to determine if there is a correlation between prenatal MR imaging results and the need for ventricular shunt placement during the neonatal period.

METHODS

The authors retrospectively reviewed the prenatal MR imaging data of 38 consecutive patients who had been referred for neurosurgical consultation following the diagnosis of ventriculomegaly. The outcome measure was placement of a ventricular shunt. Assessed parameters included prenatal atrial diameter (AD), gestational age at MR imaging, time between imaging studies, presence of concomitant CNS anomalies, laterality of ventriculomegaly, fetal sex, and temporal evolution of ventriculomegaly. Logistic regression analysis was completed with the calculation of appropriate ORs and 95% CIs.

RESULTS

Six patients (16%) required shunt placement, all with an AD > or = 20 mm (mean 23.8 mm) at the time of imaging. Eight patients had presented with an AD > or = 20 mm. Atrial diameter was the only presenting feature that correlated with shunt placement (OR 1.58, 95% CI 1.10-2.25, p = 0.01). Logistic regression analysis revealed no statistical correlation between the need for ventricular shunting and gestational age at MR imaging, time between imaging studies, fetal sex, presence of additional CNS anomalies, and laterality of the ventriculomegaly.

CONCLUSIONS

When assessed using MR imaging, an AD > or = 20 mm at any gestational age is highly associated with the need for postnatal shunting. Patients with concomitant CNS anomalies did not require shunts at a greater rate than those with isolated ventriculomegaly. Further studies are required to assess the long-term outcome of this patient population.

Prenatal mild ventriculomegaly predicts abnormal development of the neonatal brain

BACKGROUND

Many psychiatric and neurodevelopmental disorders are associated with mild enlargement of the lateral ventricles thought to have origins in prenatal brain development. Little is known about development of the lateral ventricles and the relationship of prenatal lateral ventricle enlargement with postnatal brain development.

METHODS

We performed neonatal magnetic resonance imaging on 34 children with isolated mild ventriculomegaly (MVM; width of the atrium of the lateral ventricle >/= 1.0 cm) on prenatal ultrasound and 34 age- and sex-matched control subjects with normal prenatal ventricle size. Lateral ventricle and cortical gray and white matter volumes were assessed. Fractional anisotropy (FA) and mean diffusivity (MD) in corpus callosum and corticospinal white matter tracts were determined obtained using quantitative tractography.

RESULTS

Neonates with prenatal MVM had significantly larger lateral ventricle volumes than matched control subjects (286.4%; p < .0001). Neonates with MVM also had significantly larger intracranial volumes (ICV; 7.1%, p = .0063) and cortical gray matter volumes (10.9%, p = .0004) compared with control subjects. Diffusion tensor imaging tractography revealed a significantly greater MD in the corpus callosum and corticospinal tracts, whereas FA was significantly smaller in several white matter tract regions.

CONCLUSIONS

Prenatal enlargement of the lateral ventricle is associated with enlargement of the lateral ventricles after birth, as well as greater gray matter volumes and delayed or abnormal maturation of white matter. It is suggested that prenatal ventricle volume is an early structural marker of altered development of the cerebral cortex and may be a marker of risk for neuropsychiatric disorders associated with ventricle enlargement.

How accurately does current fetal imaging identify posterior fossa anomalies?

OBJECTIVE

The first objective of our study was to describe the prevalence and spectrum of posterior fossa anomalies over 5 years in a major fetal care center where the referral diagnosis (by fetal sonography) was investigated by fetal MRI and, if confirmed, by postnatal MRI if possible. The second objective was to assess the accuracy with which fetal MRI predicts postnatal MRI findings in this population.

MATERIALS AND METHODS

We retrospectively identified all cases of suspected fetal posterior fossa anomalies referred to our center from 2002 through 2006. We reviewed maternal, fetal, neonatal, and follow-up records of all cases and fetal and early postnatal imaging studies.

RESULTS

Of the 90 cases of suspected fetal posterior fossa anomalies (by fetal sonography) referred over the study period, 60 (67%) were confirmed by fetal MRI. Of 42 live-born infants, 39 (93%) underwent postnatal MRI. There was complete agreement in fetal and postnatal MRI diagnoses in 23 infants (59%). In 16 cases (41%), fetal and postnatal MRI diagnoses disagreed; postnatal MRI excluded fetal MRI diagnoses in six cases (15%) and revealed additional anomalies in 10 cases (26%).

CONCLUSION

Although a valuable adjunct to fetal sonography in cases of suspected posterior fossa anomaly, current fetal MRI, particularly in early gestation, has limitations in accurately predicting postnatal MRI abnormalities. Advancing the accuracy of MRI for the diagnosis of posterior fossa anomalies will require greater understanding of normal brain development and improved tissue resolution of fetal MRI. During the interim, our findings strongly support the need for postnatal MRI follow-up in cases with suspected posterior fossa anomalies by fetal MRI.

FETAL NEUROIMAGING

Imaging technologies have been remarkably improved and contribute to prenatal evaluation of fetal central nervous system (CNS) development and assessment of CNS abnormalities in utero.

What does magnetic resonance imaging add to the prenatal sonographic diagnosis of ventriculomegaly?

OBJECTIVE

The purpose of this study was to determine the contribution of magnetic resonance imaging (MRI) in evaluating fetuses with the sonographic diagnosis of ventriculomegaly (VM).

METHODS

Over 4 years, consecutive fetuses with the sonographic diagnosis of VM at 1 facility who underwent prenatal MRI at a second facility were included. The roles of MRI and follow-up sonography were tabulated. The patients were analyzed in 2 groups based on the presence or absence of other central nervous system (CNS) abnormalities.

RESULTS

Twenty-six fetuses with a gestational age range of 17 to 37 weeks had sonographically detected VM (atria > or =10-29 mm), including 19 with mild VM (atria 10-12 mm). In group 1, 14 had isolated VM, 6 of which reverted to normal by the third trimester. Magnetic resonance imaging showed cerebellar hypoplasia not shown by sonography in 1 fetus and an additional finding of a mega cisterna magna in a second fetus. In group 2, 12 fetuses had VM and other CNS anomalies on sonography. Additional findings were seen with MRI in 10 of these fetuses, including migrational abnormalities (n = 4), porencephaly (n = 4), and 1 diagnosis each of abnormal myelination, hypoplasia of the corpus callosum, microcephaly, a kinked brain stem, cerebellar hypoplasia, and congenital infarction. There were significantly more fetuses with additional CNS anomalies found by MRI among those in group 2 compared with those in group 1 (Fisher exact test, P = .001).

CONCLUSIONS

Although sonography is an accurate diagnostic modality for the evaluation of fetuses with VM, MRI adds important additional information, particularly in fetuses in whom additional findings other than an enlarged ventricle are seen sonographically.

Postnatal clinical and imaging follow-up of infants with prenatal isolated mild ventriculomegaly: a series of 101 cases

BACKGROUND

Postnatal imaging and clinical outcome of fetuses with isolated mild ventriculomegaly (IMV) have never been systematically analysed.

OBJECTIVE

To evaluate the postnatal clinical outcomes of a large cohort of fetuses with IMV and to correlate them with pre- and postnatal imaging.

MATERIALS AND METHODS

We report a prospective study of 101 fetuses with IMV (10-15 mm ventriculomegaly with otherwise normal US, MRI, karyotype and TORCH screening). IMV was divided into minor (10-11.9 mm) and moderate (12-15 mm) ventriculomegaly. Ventriculomegaly was considered uni- or bilateral, stable, progressive, regressive or resolved according to the prenatal US follow-up. Clinical follow-up was performed by a neuropaediatrician. Postnatal imaging included cranial US (n = 71) and MRI (n = 76).

RESULTS

The outcome of minor and moderate IMV was excellent in 94% and 85% of infants, respectively. It was not different between uni- and bilateral IMV, and between stable, regressive and resolved IMV, and was independent of gestational age at diagnosis and gender. Fixed neurological abnormalities were observed in nine infants. Postnatal MRI showed white-matter abnormalities in 14 infants, including 6 of the 9 infants with a poor outcome.

CONCLUSION

The prognosis was slightly better in minor IMV than in moderate IMV. Postnatal MRI showed white-matter abnormalities in two-thirds of the infants with a poor outcome.

Neuropsychological outcome of children with asymmetric ventricles or unilateral mild ventriculomegaly identified in utero

DESIGN

To assess the neuropsychological outcome of children with asymmetric ventricles and unilateral ventriculomegaly identified in utero.

SETTING

Fetal neurology clinic.

POPULATION

We assessed 21 children with asymmetric ventricles (group 1) and 20 children with unilateral ventriculomegaly (group 2) identified in utero and compared them with a group of 20 children with symmetric ventricles using a formal neuropsychological tool: the Bayley Scale of Infant Development II (BSID-II).

MAIN OUTCOME MEASURES

The group of children with unilateral ventriculomegaly scored significantly lower than the control group on the mental developmental index (MDI) and on the behaviour rating scale (BRS) but not on the psychomotor index. The group of children with asymmetric ventricles did not differ significantly from the control group on either the MDI or psychomotor developmental index but differed from the latter on the BRS. Fifteen percent of the children in the asymmetric ventriculomegaly group performed two SDs below average compared with 4% of children in the asymmetrical ventricles group and none of the control.

CONCLUSION

Our results indicate that prenatally observed unilateral ventriculomegaly is a significant risk factor for developmental delay. The mental and motor outcome of children with asymmetric ventricles is similar to that of the control group, but these children are at a significant risk for behavioural abnormalities.

Fetal Ventriculomegaly

The causes of fetal ventriculomegaly vary. Ventriculomegaly can be caused by not only obstruction of cerebrospinal flow tract but also brain maldevelopment or other reasons. Recent advanced imaging technology and approaching technique of transvaginal sonography have contributed to an accurate prenatal diagnosis and clearly revealed fetal intracranial condition. However, management of the condition and counseling of parents are still difficult, because the initial cause, absolute risk, and degree of resulting neurological deficit cannot be determined with confidence. Ventriculomegaly is evaluated according to atrial width > 10 mm and mild ventriculomegaly is defined as an atrial width of 10 to 15 mm. In ventriculomegaly cases, accurate detection of intracranial structure and additional abnormalities is required. Furthermore, ventriculomegaly may resolve spontaneously or progress during pregnancy. Therefore, detailed neuroscan by advanced imaging technology, detailed extra-CNS scan, longitudinal serial scan during pregnancy are mandatory for proper counseling and management. Longitudinal observation study of not only short-term but also long-term neurological prognosis will be required.

Fetal MR Imaging

Ultrasonography is the primary prenatal screening modality used in the evaluation of the fetus and the maternal pelvis. However, fetal MR imaging plays a complementary role to prenatal ultrasound in the evaluation of the fetus with suspected abnormalities. MR imaging's role includes confirming or excluding possible lesions, defining their full extent, aiding in their characterization, and demonstrating other associated abnormalities. As newer techniques such as diffusion imaging, MR spectroscopy, and functional studies are used more widely, it is hoped that additional information will be made available by this modality to physicians evaluating and taking care of fetuses.