Natural history of fetal isolated ventriculomegaly: Comparison between pre- and post-natal imaging

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.

Hippocampal rotation is associated with ventricular atrial size

BACKGROUND

Fetal ventriculomegaly is a source of apprehension for expectant parents and may present prognostic uncertainty for physicians. Accurate prenatal counseling requires knowledge of its cause and associated findings as the differential diagnosis is broad. We have observed an association between ventriculomegaly and incomplete hippocampal inversion.

OBJECTIVE

To determine whether ventricular size is related to incomplete hippocampal inversion.

MATERIALS AND METHODS

We retrospectively evaluated pre- and postnatal brain MRIs in normal subjects (mean GA, 31 weeks; mean postnatal age, 27 days) and patients with isolated ventriculomegaly (mean GA, 31 weeks; mean postnatal age, 68 days) at a single academic medical center. Lateral ventricular diameter, multiple qualitative and quantitative markers of hippocampal inversion, and evidence of intraventricular hemorrhage were documented.

RESULTS

Incomplete hippocampal inversion and ventricular size were associated in both normal subjects (n=51) and patients with ventriculomegaly (n=32) (P<0.05). Severe ventriculomegaly was significantly associated with adverse clinical outcome in postnatal (P=0.02) but not prenatal (P=0.43) groups. In all additional cases of isolated ventriculomegaly, clinical outcome was normal over the time of assessment (mean 1±1.9 years; range 0.01 to 10 years).

CONCLUSION

Lateral ventricular atrial diameter and incomplete hippocampal inversion are associated. Less hippocampal inversion correlates with larger atria. For every 1-mm increase in fetal ventricular size, the odds of incomplete hippocampal inversion occurring increases by a factor of 1.6 in normal controls and 1.4 in patients with ventriculomegaly.

Assessment of foetal ventriculomegaly from prenatal to early postnatal period: a single-centre retrospective cohort study

The aim of this study was to evaluate the early neonatal outcomes of cases with foetal ventriculomegaly (VM) and to investigate the aetiological and prognostic factors according to the degree of VM in a single tertiary referring centre. The medical records of 87 foetuses diagnosed with VM (≥10 mm) within 6 years were evaluated. Postnatal evaluation and early neonatal prognosis were determined in 39 cases divided into two groups as mild (10-15 mm, 30 cases) and severe (>15 mm, 9 cases) according to the ventricular size. The mean gestational age at which foetal VM was detected was 22 + 3 weeks. In terms of severity, severe cases of VM were more frequent in terminated pregnancies. There was no difference in gestational age, birth weight, fifth minute Apgar scores, or cord blood gases between mild and severe cases at delivery. Isolated VM was detected in 63% of mild and 22% of severe cases. In severe cases, the need for intensive care and surgery was higher than in mild cases. Antenatal VM regressed in 50% of mild cases and 22% of severe cases. Increasing knowledge about neonatal prognosis, the factors involved in aetiology, and the degree of VM will guide the management of foetal VM.IMPACT STATEMENTWhat is already known in this subject? Some cases of foetal VM resolve spontaneously, and postnatal ultrasonography can detect normal ventricle sizes. While 74.6% of isolated VM cases show spontaneous regression, this rate is 52.1% in nonisolated cases. The gestational week at the time of diagnosis, the degree and cause of VM, intrauterine progression and the presence of any genetic, infectious, cerebral, or extracerebral disorders all influence the prognosis.What do the results of this study add? Antenatal VM regressed in 50% of mild cases and 22% of severe cases. In severe cases, the need for intensive care and surgery was higher than in mild cases. The higher frequency of accompanying cerebral findings in severe cases was striking.What are the implications of these findings for clinical practice and/or further research? The current study revealed that isolated VM with ventricular diameter less than 15 mm, after excluding out chromosomal abnormalities and prenatal infections, and no prior history of VM, has a favourable neonatal prognosis in terms of mortality and morbidity. In cases of foetal VM, increased knowledge of neonatal prognosis will guide pregnancy care and postnatal follow-up planning. Prospective multicentre studies on the neonatal period are required to bridge the gap between foetal VM and long-term consequences.

Prenatal work-up, associated anomalies and postnatal outcomes of foetuses with 9-9.9 mm cerebral ventricular atria width

OBJECTIVE

To analyse prenatal work-up, associated anomalies and postnatal outcomes of foetuses with cerebral lateral ventricular width 9-9.9 mm.

METHOD

This retrospective, observational, case-control study included 121 foetuses with initial presentation of isolated cerebral lateral ventricular width 9-9.9 mm detected during routine ultrasound scans, 21-24 weeks' gestation, in a tertiary referral centre, January 2001-December 2018. Controls included 123 foetuses with lateral ventricular width <9 mm measured under the same parameters. Clinical characteristics, obstetrical history, ultrasound findings, prenatal work-up and pregnancy outcomes were collected from medical records. Information about postnatal functional and neurodevelopmental sequelae were obtained from telephone-based questionnaires.

RESULTS

The study group had more males (82/116 (70.6%) versus 65/123 (52.8%), p = 0.004), more prenatal testing, including brain magnetic resonance imaging (28/116 (24.1%) versus 0/123 (0%), p < 0.001), echocardiography (46/116 (39.7%) versus 15/123 (12.2%), p < 0.001) and targeted anomaly scans (102/116 (87.9%) versus 1/123 (0.008%), p < 0.001). Long-term follow-up did not reveal more neurodevelopmental sequelae compared to controls. Gender-based analysis found more males with ventricular dilatation 9-9.9 mm treated for developmental delay compared to females with similar findings (15/82 (18.2%) versus 1/34 (2.9%), p = 0.010).

CONCLUSION

Foetuses with 9-9.9 mm cerebral lateral ventricular width versus <9 mm underwent more prenatal testing but had similar rates of neurodevelopmental sequelae.

Fetal Neuroimaging Update

OBJECTIVES

To review the current imaging techniques available for the evaluation of the fetal brain.

FINDINGS

Ultrasound remains the initial screening modality with routine scanning typically performed at 18-20 weeks gestation. When a central nervous system (CNS) abnormality is noted by ultrasound, MRI is increasingly being used to further clarify findings. Fetal MRI has the unique ability to provide high detailed anatomical information of the entire human fetus with high contrast resolution. This technique has grown due to the development of rapid single shot image acquisition sequences, improvement of motion correction strategies and optimizing shimming techniques.

CONCLUSIONS

The assessment of fetal CNS anomalies continues to improve. Advanced MRI techniques have allowed for further delineation of CNS anomalies and have become a cornerstone in the assessment of fetal brain well-being. Those interpreting fetal studies need to be familiar with the strengths and limitations of each exam and be sensitive to the impact discussing findings can have regarding perinatal care and delivery planning. Collaboration with neurologists, neurosurgeons, geneticists, counselors, and maternal fetal specialists are key in providing the best care to the families we treat.

Acceleration and plateau: two patterns and outcomes of isolated severe fetal cerebral ventricular dilation

OBJECTIVES

We sought to characterize patterns of in utero dilation in isolated severe fetal ventriculomegaly (ISVM) and investigate their value in predicting obstetrical and postnatal outcomes.

METHODS

This is a retrospective cohort study. ISVM was defined as a sonographic cerebral ventricle atrial with width ≥15 mm in the absence of additional cerebral or other anatomic anomalies. The aim of this study was to characterize two ISVM groups using a receiver operator curve to evaluate the rate of ventricular progression versus need for ventriculoperitoneal (VP) shunt postnatally. Outcomes were compared between the groups using Pearson's chi-squared test, Student t-test, and descriptive statistics.

RESULTS

Based on the ROC analysis, ventricular growth of ≥3 mm/week versus <3 mm/week distinguished fetuses likely to require a postnatal VP shunt. Fetuses were characterized as accelerators if ventricle growth was ≥3 mm/week at any point and plateaus if <3 mm/week. Accelerators showed a greater average rate of ventricle progression than plateaus (4.1 vs. 1.0 mm/week, respectively, p = .031) and were more likely to be delivered at earlier gestational ages (34.7 vs. 37.1 weeks respectively, p = .02). Ninety percent of accelerators demonstrated a need for shunt placement compared with 18.8% of plateaus (p < .001). Significantly more plateaus (87.5%) underwent a trial of labor while accelerators were more likely to have planned cesareans (70%, p = .009).

CONCLUSIONS

This study characterizes ISVM into two distinct populations based upon the rate of ventricle expansion, differentiated by the need for postnatal shunting. Once a ventricular growth pattern is determined, these distinctions should prove useful in prenatal management and delivery planning.

Prenatally diagnosed developmental abnormalities of the central nervous system and genetic syndromes: A practical review

Developmental brain abnormalities are complex and can be difficult to diagnose by prenatal imaging because of the ongoing growth and development of the brain throughout pregnancy and the limitations of ultrasound, often requiring fetal magnetic resonance imaging as an additional tool. As for all major structural congenital anomalies, amniocentesis with chromosomal microarray and a karyotype is the first-line recommended test for the genetic work-up of prenatally diagnosed central nervous system (CNS) abnormalities. Many CNS defects, especially neuronal migration defects affecting the cerebral and cerebellar cortex, are caused by single-gene mutations in a large number of different genes. Early data suggest that prenatal diagnostic exome sequencing for fetal CNS defects will have a high diagnostic yield, but interpretation of sequencing results can be complex. Yet a genetic diagnosis is important for prognosis prediction and recurrence risk counseling. The evaluation and management of such patients is best done in a multidisciplinary team approach. Here, we review general principles of the genetic work-up for fetuses with CNS defects and review categories of genetic causes of prenatally diagnosed CNS phenotypes.