Outcome of fetal cerebral posterior fossa anomalies

Prenatal Diagnosis and Clinical Outcomes of Isolated Mega Cisterna Magna

Objective: The study aimed to investigate the clinical outcomes of fetuses diagnosed with isolated mega cisterna magna in utero. Methods: A multicenter retrospective cohort study was conducted across 18 university hospitals from 2010 to 2019. Cases diagnosed with isolated mega cisterna magna, defined as a cisterna magna >10 mm with a normal cerebellar vermis and no cystic dilation of the fourth ventricle, were included. Cases with other central nervous system (CNS) anomalies, extra-central nervous system anomalies, chromosomal abnormalities, or congenital infections were excluded. Maternal demographics, prenatal findings, delivery outcomes, and postnatal outcomes were analyzed. Results: The mean gestational age at initial diagnosis was 28.6 ± 3.9 weeks, and the mean anteroposterior diameter of the cisterna magna was 12.5 ± 3.2 mm. Of the 71 cases initially assessed, 48 (67.6%) showed self-regression in utero. Postnatally, 13 cases (18.3%) had persistent isolated mega cisterna magna, whereas 10 cases (14.1%) were diagnosed with other central nervous system anomalies. Among the persistent isolated mega cisterna magna cases, one child exhibited delayed neurodevelopment. There was a higher incidence of isolated mega cisterna magna in male fetuses, which exhibited a significantly larger mean cisterna magna diameter compared with female fetuses (P = .045). Conclusion: Male fetuses exhibited a higher incidence of isolated mega cisterna magna compared with female fetuses and had larger anteroposterior diameters of the cisterna magna. The study demonstrated favorable neurodevelopmental outcomes associated with isolated mega cisterna magna, with self-regression observed in two-thirds of the cases. However, consecutive prenatal and postnatal evaluations for additional central nervous system or extra-central nervous system malformations need to be performed, considering the differences between prenatal and postnatal diagnoses.

Fetal and neonatal outcomes of posterior fossa anomalies: a retrospective cohort study

The primary aim of this study was to estimate the incidence of posterior fossa anomalies (PFA) and assess the associated outcomes in King Abdulaziz Medical City (KAMC), Riyadh. All fetuses diagnosed by prenatal ultrasound with PFA from 2017 to 2021 in KAMC were analyzed retrospectively. PFA included Dandy-Walker malformation (DWM), mega cisterna magna (MCM), Blake's pouch cyst (BPC), and isolated vermian hypoplasia (VH). The 65 cases of PFA were 41.5% DWM, 46.2% MCM, 10.8% VH, and 1.5% BPC. The annual incidence rates were 2.48, 2.64, 4.41, 8.75, and 1.71 per 1000 anatomy scans for 2017, 2018, 2019, 2020, and 2021, respectively. Infants with DWM appeared to have a higher proportion of associated central nervous system (CNS) abnormalities (70.4% vs. 39.5%; p-value = 0.014) and seizures than others (45% vs. 17.9%; p-value = 0.041). Ten patients with abnormal genetic testing showed a single gene mutation causing CNS abnormalities, including a pathogenic variant in MPL, C5orf42, ISPD, PDHA1, PNPLA8, JAM3, COL18A1, and a variant of uncertain significance in the PNPLA8 gene. Our result showed that the most common PFA is DWM and MCM. The autosomal recessive pathogenic mutation is the major cause of genetic disease in Saudi patients diagnosed with PFA.

Dandy-Walker syndrome associated with a giant occipital meningocele: A case report and a literature review

Background

Dandy-Walker malformation or syndrome is the most common posterior fossa malformation. It is commonly associated with other congenital anomalies such as cardiac defects; however, association with a giant occipital meningocele is extremely rare, as only around 34 cases have been described.

Case description

We report a case of a 2-month-old female infant who presented with a midline, gigantic mass in the back of the head. It was first discovered on a prenatal ultrasound. The mass measured about 15 × 5 cm, extending to the midback, not changing in size with crying, not attached to the back, and with a positive transillumination test. The diagnosis was confirmed after doing a brain computed tomography, which revealed hypoplasia of the vermis with an enlarged posterior fossa as well as cystic dilation of both ventricles with herniation through a bone defect.

Conclusion

Our case highlights a rare association between giant occipital meningocele and Dandy-Walker syndrome that is rarely discussed or reported in the medical literature. By reporting this extremely rare case of Dandy-Walker syndrome associated with a giant occipital meningocele, we hope to contribute to the creation of a database for future research so that a management protocol can be established for use by clinicians and neurosurgeons for better management of the condition.

Relative prevalence and outcome of fetal posterior fossa abnormality

AIM

To find out the relative incidence and outcome of posterior fossa abnormality (PFA) in terms of survival at birth until 2 years of age.

METHODS

We conducted a prospective study; all fetuses diagnosed with posterior fossa abnormality were followed-up. The outcome was observed with respect to survival, the presence of associated anomalies, the existence of developmental delay after a telephonic interview.

RESULTS

Out of 2703 children with congenital anomalies, 921 (34.1%) had a central nervous system defect; 76 cases of PFA were fully followed. Dandy-Walker malformation (DWM) was present in 50% (38/76), mega cisterna magna 18.4% (14/76), Blake pouch cyst 13.2% (10/76), vermian hypoplasia (VH) 13.2% (10/76) and arachnoid cyst 5.2% (4/76). The diagnosis was possible before 20 weeks in only 12 (15.8%) cases. The mean gestational age at delivery was 34.7 ± 6.7 weeks. Associated anomalies were seen in 35/76 (46.1%) cases. A total of 35/76 (46.1%) survived after 2 years; there was developmental delay in 9.2% of cases.

CONCLUSION

There is a large variation in the outcome of PFA depending upon the type of anomaly. Associated anomalies are common in VH and DWM, making their prognosis worse.

Dandy-Walker malformation and variants: clinical features and associated anomalies in 28 affected children-a single retrospective study and a review of the literature

OBJECTIVE

To investigate the clinical characteristics, the neuroimaging features and associated anomalies observed in children affected by Dandy-Walker malformations (DWM) and variants (DWV) in a single tertiary hospital in Catania and compare our data to their existent in the literature.

METHODS

A retrospective case series using the medical records has been performed on 28 children diagnosed with DWM and DWV admitted to a single tertiary section of Pediatric Neurology, Department of Catania, Italy from January 2005 to January 2021. We reviewed the neuroimaging using the new diagnostic criteria of Klein et al. RESULTS: Associated anomalies were frequently reported. Among these, hydrocephalus was found in 13/28 (48%), and hydrocephalus plus corpus callosum anomalies in three children (10%). We described corpus callosum, cardiac and genitourinary anomalies in 2/28 (7%), 3/28 (10%), and 3/28 (10%), respectively. The most common clinical features were the developmental delay and epilepsy observed in 19/28 (67%) and in 9/28 (32%) of the cases. The first exam at the diagnosis was MRI in 17/28 patients, followed by transfontanellar ultrasound in 5/28, computed tomography in 4/28 and prenatal ultrasound in 2/28. To note, a child with DWM was affected by Down syndrome and one by congenital disorders of N-linked glycosylation (CDG-IId).

CONCLUSIONS

Children with DWV were more commonly observed than children with DWM. Hydrocephalus is an anomaly, frequently and equally reported in both DWM and DMV. Perinatal complications were frequent adverse events with severe respiratory distress and need for cardiopulmonary resuscitation. Cognitive involvement and epilepsy were the most common comorbidities. Single DWV is associated with a better developmental outcome.

Are fetal gender and gestational age related to the size of cisterna magna?

OBJECTIVES

The purpose of this article was to explore whether the gestational age(GA)and gender could affect the size of the cisterna magna (CM).

METHODS

This study that included pregnant women who were between 20 ∼ 39⁺⁶. The recorded included BPD, HC, anteroposterior diameter of CM and gender. The fetuses were divided into normal and isolated enlargement of the CM (IECM)group for statistical analysis.

RESULTS

Seven hundred ninety six fetuses with normal CM, 412 cases were boys and 384 cases were girls. 73 fetuses with IECM, 59 cases were boys and 14 cases were girls. The anteroposterior diameter of the CM increased with GA during 20-26⁺⁶weeks. After 27 weeks, the anteroposterior diameter of CM became stable. In the IECM group, the mean anteroposterior of male and female fetuses were 1.31 ± 0.18 cm and 1.24 ± 0.15 cm, respectively. The IECM fetus accounted for 8.4% of the total number of fetuses, male IECM accounted for 14.3% of normal male fetus, and female fetus was 3.6%, which showed that male fetus had a higher rate of IECM than female (χ2 = 21.6, p<.001).

CONCLUSIONS

There is a gender difference between normal fetuses and IECM fetuses. Based on our finding, it is reasonable to establish the normal value of CM according to the gender difference.

Fetal brain biometry in isolated mega cisterna magna: MRI and US study

OBJECTIVE

To characterize the biometric parameters in ultrasound and brain MRI of fetuses with isolated mega cisterna magna (MCM).

METHODS

Cross-sectional historical cohort study conducted at a single tertiary medical center between 2011 and 2018. All fetuses underwent US and brain MRI scans. Matching analysis was performed according to gender and gestational age.

RESULTS

The study included a total of 103 fetuses; 44 fetuses with isolated MCM in the study group, and a control group of 59 fetuses with normal CNS. The study group had larger biparietal diameter (BPD) (86 vs. 79.8 mm, p = .001) and head circumference (HC) (318 vs. 292 mm, p < .001) on ultrasound. On MRI, study group had larger occipitofrontal diameter (OFD) (99 vs. 92 mm, p < .001) and BPD (77 vs. 72 mm, p < .001). Male fetuses' prevalence was higher in the study group (77.3% vs. 47.5%). After matching 20 fetuses from each group, the study group had larger HC (310.1 versus 300.7 mm, p = .029) and OFD (113.4 versus 108.3 mm, p = .009) on ultrasound, and larger OFD (97.4 versus 94.6, p = .013) on brain MRI.

CONCLUSIONS

Isolated MCM may be related to other large fetal CNS biometric measurements in both ultrasound and MRI and might be influenced by fetal gender.

Prenatal assessment of cerebellar vermian lobulation: fetal MRI with 3-Tesla postmortem validation

OBJECTIVES

To optimize the imaging assessment of fetal hindbrain malformations, this observational magnetic resonance imaging (MRI) study aimed to assess whether fetal vermian lobulation can be quantified accurately and whether the relative growth of vermian lobules is uniform.

METHODS

This retrospective study included singleton fetuses which underwent T2-weighted MRI in vivo with a 1.5-Tesla (T) scanner or within 24 h postmortem with a 3-T scanner between January 2007 and November 2016 at the Medical University of Vienna. We included only those showing normal structural brain development on ultrasound and MRI and which had image quality appropriate for quantitative analysis, i.e. good image quality and a precise midsagittal slice. Fetal brains were segmented and, for all discernible vermian lobules, we determined the mean relative area contribution (MRAC, the proportion of the lobule relative to the total vermian area, in terms of number of voxels). Inter- and intrarater measurement variability of a representative selection (21 cases) was determined by intraclass correlation coefficient (ICC) for voxel-based differences. A linear regression model was used to assess the correlation between the relative size of each vermian lobule (i.e. MRAC) and gestational age.

RESULTS

A total of 78 fetuses scanned in vivo aged 18-32 gestational weeks and seven fetuses scanned postmortem aged 16-30 weeks had a precise midsagittal slice and image quality sufficient for quantitative analysis. After 22 weeks of gestation, seven of the nine known vermian lobules could be discriminated reliably. The MRAC showed a mean ± SD difference of only 2.89 ± 3.01% between in-vivo and postmortem measurements. The ICC of voxel-based interrater differences was mean ± SD, 0.91 ± 0.05 and the intrarater ICC was 0.95 ± 0.03. Growth of cerebellar lobules was non-uniform: the MRAC of culmen and DFT (declive + folium + tuber) increased with gestational age, whereas that of lingula, centralis, pyramis and nodulus decreased. The growth of the uvula showed no significant correlation with gestational age.

CONCLUSIONS

Fetal vermian lobulation can be assessed accurately and reliably after 22 weeks on precise midsagittal sequences with 1.5-T T2-weighted MRI. Fetal vermian lobules show non-uniform growth, with expansion of DFT and culmen at the expense of the other vermian lobules. Evaluation and elucidation of vermian lobulation in normal fetuses should enable better characterization of fetuses with hindbrain malformations. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

The Impact of Prenatal Diagnosis of Selected Central Nervous System Anomalies for Prenatal Counselling Based on Significant Pregnancy Morbidity and Neonatal Outcomes

BACKGROUND & OBJECTIVES

Prenatal screening and diagnostic imaging advances have led to an increased detection of CNS anomalies, including ventriculomegaly/congenital hydrocephalus (HCP), Dandy-Walker malformation (DWM), and myelomeningocele (MMC). Data on pregnancy outcomes and the impact of prenatal diagnosis on neonatal outcomes is limited. Our study aimed to provide data on obstetric and neonatal outcomes following prenatal diagnosis of one of three CNS anomalies.

METHODS

A retrospective search of two databases in Alberta, Canada and NICU chart review of cases between 2001 and 2011was completed. Primary outcomes for each group were pregnancy outcome (live birth, stillbirth, and termination) and detection rate. Secondary outcomes were live and total birth prevalence, mode of delivery, GA at delivery, and length of NICU stay for inborn versus outborn patients.

RESULTS

Prenatal detection rates were 91.6% (HCP), 83.4% (DWM), and 92.9 % (MMC). Termination rates were 30.2% (DWM), 34.2% (HCP), and 48.5% (MMC). Median GA (weeks, range) at diagnosis were 22 (17-38), 20 (12-37), and 20.5 (18-34) for HCP, DWM, and MMC, respectively. Rate of Caesarean section for fetal indication was 50.0%, 44.4%, and 42.9% for HCP, DWM, and MMC, respectively. Median NICU length of stay was longer for outborn patients than inborn patients and were as follows: (range) 33.0 (21-38) versus 8.5 (1-49) d (HCP), and 29 (29-57) versus 14 (2-75) d (DWM).

CONCLUSION

This study provides termination rates, obstetric interventions, and NICU length of stay for prenatally-identified CNS anomalies. Collectively, this study assists prenatal counselling women with a fetus affected by a described CNS anomaly.

Diagnostic imaging of posterior fossa anomalies in the fetus

Ultrasound and magnetic resonance imaging are the two imaging modalities used in the assessment of the fetus. Ultrasound is the primary imaging modality, whereas magnetic resonance is used in cases of diagnostic uncertainty. Both techniques have advantages and disadvantages and therefore they are complementary. Standard axial ultrasound views of the posterior fossa are used for routine scanning for fetal anomalies, with additional orthogonal views directly and indirectly obtainable using three-dimensional ultrasound techniques. Magnetic resonance imaging allows not only direct orthogonal imaging planes, but also tissue characterization, for example to search for blood breakdown products. We review the nomenclature of several posterior fossa anomalies using standardized criteria, and we review cerebellar abnormalities based on an etiologic classification.

The genetics of cerebellar malformations

The cerebellum has long been recognized for its role in motor co-ordination, but it is also increasingly appreciated for its role in complex cognitive behavior. Historically, the cerebellum has been overwhelmingly understudied compared to the neocortex in both humans and model organisms. However, this tide is changing as advances in neuroimaging, neuropathology, and neurogenetics have led to clinical classification and gene identification for numerous developmental disorders that impact cerebellar structure and function associated with significant overall neurodevelopmental dysfunction. Given the broad range in prognosis and associated medical and neurodevelopmental concerns accompanying cerebellar malformations, a working knowledge of these disorders and their causes is critical for obstetricians, perinatologists, and neonatologists. Here we present an update on the genetic causes for cerebellar malformations that can be recognized by neuroimaging and clinical characteristics during the prenatal and postnatal periods.

Systematic review and meta-analysis of isolated posterior fossa malformations on prenatal imaging (part 2): neurodevelopmental outcome

OBJECTIVES

Diagnosis of isolated posterior fossa anomalies in children is biased by the fact that only those that are symptomatic are brought to the attention of the appropriate clinical personnel, and the reported rate is often affected by the adoption of different nomenclature, diagnostic criteria, outcome measures, duration of follow-up and neurodevelopmental tools. The aim of this systematic review was to explore the neurodevelopmental outcome of fetuses with a prenatal diagnosis of isolated posterior fossa anomalies.

METHODS

MEDLINE and EMBASE were searched electronically, utilizing combinations of the relevant medical subject heading terms for 'posterior fossa' and 'outcome'. Studies assessing the neurodevelopmental outcome in children with a prenatal diagnosis of isolated posterior fossa malformations were considered eligible. The posterior fossa anomalies analyzed included Dandy-Walker malformation (DWM), mega cisterna magna (MCM), Blake's pouch cyst (BPC) and vermian hypoplasia (VH). Two authors reviewed all abstracts independently. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for cohort studies. Meta-analyses of proportions were used to combine data, and between-study heterogeneity was explored using the I(2) statistic.

RESULTS

A total of 1640 articles were identified; 95 were assessed for eligibility and a total of 16 studies were included in the systematic review. The overall rate of abnormal neurodevelopmental outcome in children with a prenatal diagnosis of DWM was 58.2% (95% CI, 21.8-90.0%) and varied from 0-100%. In those with a prenatal diagnosis of MCM, the rate of abnormal neurodevelopmental outcome was 13.8% (95% CI, 7.3-21.9%), with a range of 0-50%. There was no significant association between BPC and the occurrence of abnormal neurodevelopmental delay, with a rate of 4.7% (95% CI, 0.7-12.1%) and range of 0-5%. Although affected by the very small number of studies, there was a non-significant occurrence of abnormal neurodevelopmental delay in children with a prenatal diagnosis of VH, with a rate of 30.7% (95% CI, 0.6-79.1%) and range of 0-100%.

CONCLUSIONS

Fetuses diagnosed with isolated DWM are at high risk of abnormal neurodevelopmental outcome, while isolated MCM or BPC have a generally favorable outcome. The risk of abnormal developmental delay in cases with isolated VH needs to be further assessed. In view of the wide heterogeneity in study design, time of follow-up, neurodevelopmental tests used and the very small number of included cases, further future large prospective studies with standardized and objective protocols for diagnosis and follow-up are needed in order to ascertain the rate of abnormal neurodevelopmental outcome in children with isolated posterior fossa anomalies. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Systematic review and meta-analysis of isolated posterior fossa malformations on prenatal ultrasound imaging (part 1): nomenclature, diagnostic accuracy and associated anomalies

OBJECTIVE

To explore the outcome in fetuses with prenatal diagnosis of posterior fossa anomalies apparently isolated on ultrasound imaging.

METHODS

MEDLINE and EMBASE were searched electronically utilizing combinations of relevant medical subject headings for 'posterior fossa' and 'outcome'. The posterior fossa anomalies analyzed were Dandy-Walker malformation (DWM), mega cisterna magna (MCM), Blake's pouch cyst (BPC) and vermian hypoplasia (VH). The outcomes observed were rate of chromosomal abnormalities, additional anomalies detected at prenatal magnetic resonance imaging (MRI), additional anomalies detected at postnatal imaging and concordance between prenatal and postnatal diagnoses. Only isolated cases of posterior fossa anomalies - defined as having no cerebral or extracerebral additional anomalies detected on ultrasound examination - were included in the analysis. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for cohort studies. We used meta-analyses of proportions to combine data and fixed- or random-effects models according to the heterogeneity of the results.

RESULTS

Twenty-two studies including 531 fetuses with posterior fossa anomalies were included in this systematic review. The prevalence of chromosomal abnormalities in fetuses with isolated DWM was 16.3% (95% CI, 8.7-25.7%). The prevalence of additional central nervous system (CNS) abnormalities that were missed at ultrasound examination and detected only at prenatal MRI was 13.7% (95% CI, 0.2-42.6%), and the prevalence of additional CNS anomalies that were missed at prenatal imaging and detected only after birth was 18.2% (95% CI, 6.2-34.6%). Prenatal diagnosis was not confirmed after birth in 28.2% (95% CI, 8.5-53.9%) of cases. MCM was not significantly associated with additional anomalies detected at prenatal MRI or detected after birth. Prenatal diagnosis was not confirmed postnatally in 7.1% (95% CI, 2.3-14.5%) of cases. The rate of chromosomal anomalies in fetuses with isolated BPC was 5.2% (95% CI, 0.9-12.7%) and there was no associated CNS anomaly detected at prenatal MRI or only after birth. Prenatal diagnosis of BPC was not confirmed after birth in 9.8% (95% CI, 2.9-20.1%) of cases. The rate of chromosomal anomalies in fetuses with isolated VH was 6.5% (95% CI, 0.8-17.1%) and there were no additional anomalies detected at prenatal MRI (0% (95% CI, 0.0-45.9%)). The proportions of cerebral anomalies detected only after birth was 14.2% (95% CI, 2.9-31.9%). Prenatal diagnosis was not confirmed after birth in 32.4% (95% CI, 18.3-48.4%) of cases.

CONCLUSIONS

DWM apparently isolated on ultrasound imaging is a condition with a high risk for chromosomal and associated structural anomalies. Isolated MCM and BPC have a low risk for aneuploidy or associated structural anomalies. The small number of cases with isolated VH prevents robust conclusions regarding their management from being drawn. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

A fetopathological and clinical study of the Dandy-Walker malformation and a literature review

Aim: The Dandy-Walker malformation is a rare abnormality of the central nervous system pertaining to the group of cystic malformations. The frequency of occurrence of the malformation ranges from 1:800 to 35,000 live births. The aim of this study is to investigate the Dandy-Walker malformation in two cases – one by autopsy after abortion due to medical indications during the 25th gestational week at The Clinic of Embryo and Fetopathology, Center for Maternity and Neonatology, Tunis, Tunisia, and another case of a 1-year-old infant diagnosed with an acute internal hydrocephalus at The Clinic of Neurosurgery, Medical University Plovdiv, Bulgaria, and to compare the results with those in the literature.

Results: Both cases are of an isolated Dandy-Walker malformation without any associated abnormalities of the central nervous system and other organs and systems. After the placement of a ventriculoperitoneal shunt in the second case, the child’s condition was greatly improved.

Conclusion: The question arises whether the prenatal diagnosis of an isolated Dandy-Walker malformation is an indication for pregnancy termination, and who and after what examinations has the right to make this decision, given the favorable outcome after surgical treatment.

Mortality of Dandy-Walker syndrome in the United States: Analysis by race, gender, and insurance status

BACKGROUND

Dandy-Walker syndrome (DWS) is a congenital disorder often diagnosed in early childhood. Typically manifesting with signs/symptoms of increased intracranial pressure, DWS is catastrophic unless timely neurosurgical care can be administered via cerebrospinal fluid (CSF) drainage. The rates of mortality, adverse discharge disposition (ADD), and CSF drainage in DWS may not be uniform regardless of race, gender or insurance status; such differences could reflect disparities in access to neurosurgical care. This study examines these issues on a nationwide level.

MATERIALS AND METHODS

The Kids' Inpatient Database spanning 1997-2003 was used for analysis. Only patients admitted for DWS (ICD-9-CM = 742.3) were included. Multivariate analysis was adjusted for several variables, including patient age, race, sex, admission type, primary payer, income, and hospital volume.

RESULTS

More than 14,000 DWS patients were included. Increasing age predicted reduced mortality (OR = 0.87; P < 0.05), ADD (OR = 0.96; P < 0.05), and decreased likelihood of receiving CSF drainage (OR = 0.86; P < 0.0001). Elective admission type predicted reduced mortality (OR = 0.29; P = 0.0008), ADD (OR = 0.68; P < 0.05), and increased CSF drainage (OR = 2.02; P < 0.0001). African-American race (OR = 1.20; P < 0.05) and private insurance (OR = 1.18; P < 0.05) each predicted increased likelihood of receiving CSF drainage, but were not predictors of mortality or ADD. Gender, income, and hospital volume were not significant predictors of DWS outcome.

CONCLUSION

Increasing age and elective admissions each decrease mortality and ADD associated with DWS. African-American race and private insurance status increase access to CSF drainage. These findings contradict previous literature citing African-American race as a risk factor for mortality in DWS, and emphasize the role of private insurance in obtaining access to potentially lifesaving operative care.

Reference ranges of fetal cisterna magna length and area measurements by 3-dimensional ultrasonography using the multiplanar mode

This study aimed to establish reference values for the length and area of the fetal cisterna magna using the multiplanar mode of 3-dimensional ultrasonography. A cross-sectional study including 224 normal pregnant women between 17 weeks 0 days and 29 weeks 6 days of gestation was carried out. The area and length of the fetal cisterna magna were measured in the axial plane at the level of the cerebellar transverse diameter. Reliability was determined by intraclass correlation coefficient. The mean length and area of the fetal cisterna magna ranged from 0.50 ± 0.10 to 0.79 ± 0.18 cm and 0.95 ± 0.18 to 3.09 ± 0.62 cm(2), respectively. Intraobserver reliability for the length and area (intraclass coefficients: 0.86 and 0.91, respectively) and interobserver reliability (intraclass coefficients: 0.64 and 0.82, respectively) were good. Three-dimensional ultrasonography using the multiplanar mode is a reliable method for the determination of reference values for the length and area of the fetal cisterna magna.

Multidimensional analysis of fetal posterior fossa in health and disease

Fetal magnetic resonance imaging (MRI) is now routinely used to further investigate cerebellar malformations detected with ultrasound. However, the lack of 2D and 3D biometrics in the current literature hinders the detailed characterisation and classification of cerebellar anomalies. The main objectives of this fetal neuroimaging study were to provide normal posterior fossa growth trajectories during the second and third trimesters of pregnancy via semi-automatic segmentation of reconstructed fetal brain MR images and to assess common cerebellar malformations in comparison with the reference data. Using a 1.5-T MRI scanner, 143 MR images were obtained from 79 normal control and 53 fetuses with posterior fossa abnormalities that were grouped according to the severity of diagnosis on visual MRI inspections. All quantifications were performed on volumetric datasets, and supplemental outcome information was collected from the surviving infants. Normal growth trajectories of total brain, cerebellar, vermis, pons and fourth ventricle volumes showed significant correlations with 2D measurements and increased in second-order polynomial trends across gestation (Pearson r, p < 0.05). Comparison of normal controls to five abnormal cerebellum subgroups depicted significant alterations in volumes that could not be detected exclusively with 2D analysis (MANCOVA, p < 0.05). There were 15 terminations of pregnancy, 8 neonatal deaths, and a spectrum of genetic and neurodevelopmental outcomes in the assessed 24 children with cerebellar abnormalities. The given posterior fossa biometrics enhance the delineation of normal and abnormal cerebellar phenotypes on fetal MRI and confirm the advantages of utilizing advanced neuroimaging tools in clinical fetal research.

Main congenital cerebral anomalies: how prenatal imaging aids counseling

The purpose of this article is to discuss some common cerebral lesions that may be detected during prenatal screening: corpus callosum dysgenesis, absent septum pellucidum, localized parenchymal ischemic-hemorrhagic lesions, megacisterna magna, Blake's pouch cyst, posterior fossa arachnoid cyst and Dandy-Walker malformation. For each cerebral defect, the main imaging findings are reminded, certain differential diagnoses are discussed and prenatal diagnostic accuracy is analyzed with emphasis on uncertainties encountered during analysis of ultrasound or magnetic resonance images. Detecting cerebral lesions in fetuses requires rapid counseling by neuropediatricians. Keeping in mind that the prenatal diagnostic accuracy is not 100%, the neuropediatricians have to answer the parents' questions regarding the outcome of the unborn child as well as the risk of recurrence for future pregnancies. This article is based on the authors' large experience in both prenatal imaging and neurocounseling. The frequently asked questions are set up. Answers are provided, underscoring the importance of an appropriate description of the cerebral defect, and therefore the pivotal role of prenatal imaging. However, prenatal neurocounseling remains challenging and the parents must be aware of uncertainties regarding both diagnostic accuracy and prognostic evaluation.

Normative data for fetal cisterna magna length measurement between 18 and 24 weeks of pregnancy

PURPOSE

The aim of this study was to determine normative data for fetal cisterna magna length (CML) measurement in a Brazilian population.

METHODS

This was a retrospective cross-sectional study on 3,862 normal singleton pregnancies between the 18th and 24th weeks of pregnancy. Fetal CML was measured in the axial plane of the fetal head, at lateral ventricle level, including the cavum septum pellucidum, thalamus, third ventricle, and transverse cerebellar diameter. The anteroposterior measurement was made between the posterior border of the cerebellar vermis and the internal face of the occipital bone. To assess the correlation between CML and gestational age (GA), polynomial equations were calculated, with adjustments using determination coefficient (R2).

RESULTS

The mean CML ranged from 4.29±0.93 mm at 18 to 18+6 weeks to 5.58±1.23 mm at 24 to 24+6 weeks of pregnancy. There was a good correlation between CML and GA, best represented by a linear equation: CML=0.535+0.208*GA (R2=0.084).

CONCLUSION

We established normative data for fetal CML in the second trimester of pregnancy, in a large Brazilian population.

Perinatal and short-term neonatal outcomes of posterior fossa anomalies

OBJECTIVE

To describe the perinatal and neonatal outcomes for fetuses with posterior fossa (PF) anomalies - mega-cisterna magna (MCM), persistent Blake's pouch (PBP) or the Dandy-Walker continuum (DWC) - using a new classification.

METHODS

46 cases with PF anomaly diagnosed on ultrasound (US) between 16 and 28 weeks' gestation were included. The images were reviewed and classified as one of the following: MCM, PBP or DWC. Outcomes were obtained from patient records.

RESULTS

30 cases with DWC, 6 with MCM, and 10 with PBP were identified. Associated anomalies were present in all groups, but more frequent in DWC. Agenesis of the corpus callosum and ventriculomegaly were more common in DWC than in MCM or PBP. Only fetuses with DWC were found to have chromosomal abnormalities. Perinatal outcomes differed significantly, with terminations of pregnancy more frequent in DWC. In the immediate postnatal period, infants with DWC had worse outcomes than those with MCM and PBP. Across all groups, those with associated anomalies had worse outcomes than those with an isolated PF anomaly.

CONCLUSION

Infants antenatally diagnosed with DWC had worse perinatal and short-term neonatal outcomes than those with MCM or PBP. Those with associated anomalies had uniformly poorer outcomes than those with isolated anomalies.

Adverse neurodevelopmental outcomes after exposure to phenobarbital and levetiracetam for the treatment of neonatal seizures

OBJECTIVE

Compare neurodevelopment after levetiracetam (LEV) and phenobarbital (PB) for neonatal seizures.

STUDY DESIGN

Retrospective study of infants who received antiepileptic drugs (AEDs) for neonatal seizures. Effect of cumulative exposure to LEV and PB on outcomes of death, cerebral palsy (CP) and Bayley Scales of Infant Development (BSID) scores were evaluated at 24 months corrected age. Analyses were adjusted for number of electrographic seizures and gestational age.

RESULT

In 280 infants with comparable seizure etiology and cranial imaging results, increased exposure to PB was associated with worse BSID cognitive and motor scores (8.1- and 9-point decrease per 100 mg kg(-1); P=0.01). The effect was less with LEV (2.2- and 2.6-point decrease per 300 mg kg(-1) LEV (P=0.01)). CP probability increased by 2.3-fold per 100 mg kg(-1) PB and was not associated with increasing LEV.

CONCLUSION

Increased exposure to PB is associated with worse neurodevelopmental outcomes than LEV. Prospective studies of outcomes of neonatal exposure to AEDs are essential.

Reassessment of the normal fetal cisterna magna during gestation and an alternative approach to the definition of cisterna magna dilatation

INTRODUCTION

Cisterna magna (CM) measurement constitutes part of the sonographic assessment of the posterior fossa. CM enlargement (ECM) is defined as a measurement exceeding 10 mm, although it has previously been noted that the CM varies in size with gestation. Existing data do not appear to reflect observations regarding CM biometry within our population and this study was therefore undertaken in order to re-evaluate CM biometry.

MATERIALS AND METHODS

Data from 4,750 normal pregnancies between 15 and 32 weeks of gestation were collected and used to construct a reference range for the CM.

RESULTS

Regression analysis was used to model CM across gestational age and thereby define the upper limits for normal CM measurements across gestation. The CM increases with gestation. These data suggest that a 10-mm cut-off underestimates ECM, notably in the gestational age period below 24 weeks, whilst overestimating isolated ECM beyond this. Differences in CM measurements between genders were confirmed (p < 0.0001).

CONCLUSIONS

Defining ECM based upon a cut-off of 10 mm across all gestations may be inappropriate given the variation observed with gestational age. More accurate identification of fetuses with, in particular, isolated ECM may facilitate more precise evaluation of the clinical significance of this finding.

Midbrain and hindbrain malformations: advances in clinical diagnosis, imaging, and genetics

Historically, the midbrain and hindbrain have been considered of secondary importance to the cerebrum, which has typically been acknowledged as the most important part of the brain. In the past, radiologists and pathologists did not regularly examine these structures-also known as the brainstem and cerebellum-because they are small and difficult to remove without damage. With recent developments in neuroimaging, neuropathology, and neurogenetics, many developmental disorders of the midbrain and hindbrain have emerged as causes of neurodevelopmental dysfunction. These research advances may change the way in which we treat these patients in the future and will enhance the clinical acumen of the practising neurologist and thereby improve the diagnosis and treatment of these patients.

Comparison of Fetal Cerebellum and Cisterna Magna Length by 2D and 3D Ultrasonography between 18 and 24 Weeks of Pregnancy

To compare the fetal cerebellum and cisterna magna length measurements by means of two- (2DUS) and three-dimensional (3DUS) ultrasonography using the three-dimensional extended imaging (3D XI), a cross-sectional study with 69 healthy pregnant women between 18 and 24 weeks was performed. For the measurements by 2DUS, the axial planes were used and for the 3DUS a sequence of adjacent axial slices (multislice view). To evaluate the difference between the two techniques, we used the Wilcoxon test. To evaluate the correlation between the cerebellum and cisterna magna length measurements and the gestational age, we used the Spearman correlation coefficient (r). For the calculation of reproducibility, we used the intraclass correlation coefficient (ICC). The mean of the transverse and anterior-posterior diameter of cerebellum and cisterna magna by 3DUS was 9.23 and 6.62 mm, respectively. It was observed that the average of the measurements obtained by 3DUS was significantly higher, 0.76 and 1.02 mm for the length of the cerebellum and cisterna magna, respectively (P < 0.001). There was a high correlation between the length measurement of the cerebellum 3D (r = 0.940, P < 0.001), but low correlation of cisterna magna 3D (r = 0.462, P = 0.080) with the gestational age. There was good intra- and interobserver reproducibility for the cerebellum and cisterna magna 3D with ICC = 0.792 , 0.668, 0.691, and 0.287, respectively. The measurements of the fetal cerebellum and cisterna magna length by 3DUS using the software 3D XI were significantly higher than those obtained by 2DUS.

Detection rates of clinically significant genomic alterations by microarray analysis for specific anomalies detected by ultrasound

OBJECTIVE

The aim of this study is to understand the diagnostic utility of comparative genomic hybridization (CGH)-based microarrays for pregnancies with abnormal ultrasound findings.

METHODS

We performed a retrospective analysis of 2858 pregnancies with abnormal ultrasounds and normal karyotypes (when performed) tested in our laboratory using CGH microarrays targeted to known chromosomal syndromes with later versions providing backbone coverage of the entire genome. Abnormalities were stratified according to organ system involvement. Detection rates for clinically significant findings among these categories were calculated.

RESULTS

Clinically significant genomic alterations were identified in cases with a single ultrasound anomaly (n = 99/1773, 5.6%), anomalies in two or more organ systems (n = 77/808, 9.5%), isolated growth abnormalities (n = 2/76, 2.6%), and soft markers (n = 2/77, 2.6%). The following anomalies in isolation or with additional anomalies had particularly high detection rates: holoprosencephaly (n = 9/85, 10.6%), posterior fossa defects (n = 21/144, 14.6%), skeletal anomalies (n = 15/140, 10.7%), ventricular septal defect (n = 14/132, 10.6%), hypoplastic left heart (n = 11/68, 16.2%), and cleft lip/palate (n = 14/136, 10.3%).

CONCLUSIONS

Microarray analysis identified clinically significant genomic alterations in 6.5% of cases with one or more abnormal ultrasound findings; the majority were below the resolution of karyotyping. Larger data sets such as this allow for sub-stratification by specific anomalies to determine risks for genomic alterations detectable by microarray analysis.

Patterns of cognitive and fine motor deficits in a case of Dandy-Walker continuum

Cerebellar vermian hypoplasia in the context of Dandy-Walker complex is a relatively common disorder associated with a variety of cognitive and behavioral deficits in addition to impairment in motor control. Few studies, however, have examined the neuropsychological profiles of children with isolated hypoplasias of the cerebellum. Herein, we report a 6-year-old girl with Dandy-Walker continuum presenting with mild mental retardation and an inability to produce intelligible speech, despite adequate comprehension of single items and simple instructions. She was able to articulate vowels but not consonants, and fine motor function was deficient. Visual memory was intact for single items but not for multiple items, and visuospatial perception was impaired. An inability to form intelligible speech is not typically reported in cases of isolated vermian hypoplasia. The case extends our knowledge of the phenotypes associated with cerebellar hypoplasia and its relation to fine motor and articulatory control.

Giant occipital meningocele in an 8-year-old child with Dandy-Walker malformation

INTRODUCTION

The possibility of an association between Dandy-Walker malformation and occipital meningocele is well-known. However, just an overall number of about 40 cases have been previously reported. Giant occipital meningocele has been described only in three newborns. Incidence, pathology, clinical presentation, and proper management of this association are still poorly defined.

REPORT OF THE CASE

An 8-year-old boy with Dandy-Walker malformation and giant (25 cm in diameter) occipital meningocele is presented. This boy was born without any apparent occipital mass and harbored no other significant malformations including hydrocephalus. On admission, he was neurologically intact and the giant occipital mass presented partially calcified cyst walls. Treatment consisted of the excision of the occipital malformation, cranioplasty, and cysto-peritoneal shunt. Outcome was excellent.

CONCLUSIONS

To the best of our knowledge, among the few reported patients with Dandy-Walker malformation associated to occipital meningocele, this is the oldest one and the one with the largest occipital meningocele; he is unique with calcified walls of the occipital meningocele and the only one who survived the repair of the giant malformation. In Dandy-Walker malformation, occipital meningocele may develop and grow regardless of hydrocephalus. Giant size may be reached and the cyst may become calcified. Surgical repair may warrant favorable outcome.

Use of clomiphene citrate and birth defects, National Birth Defects Prevention Study, 1997-2005

BACKGROUND

Clomiphene citrate (CC) is the first line drug for subfertility treatment. Studies assessing the association between CC and birth defects have been inconclusive.

METHODS

We used data from the National Birth Defects Prevention Study, a population-based, multi-site case-control study of major birth defects. Women from 10 US regions with deliveries affected by at least one of >30 birth defects (cases) and mothers of live born infants without a major birth defect (controls) who delivered October 1997-December 2005 were interviewed. The exposure of interest was reported CC use in the period from 2 months before conception through the first month of pregnancy. Women who conceived using assisted reproductive technology were excluded. Thirty-six birth defect categories with at least three exposed cases were studied. Multiple logistic regression was used to control for potential confounders.

RESULTS

CC use was reported by 1.4% of control mothers (94/6500). Among 36 case-groups assessed, increased adjusted odds ratios (aOR) were found [all: aOR, 95% confidence interval (CI)] for anencephaly (2.3, 1.1-4.7), Dandy-Walker malformation (4.4, 1.7-11.6), septal heart defects (1.6, 1.1-2.2), muscular ventricular septal defect (4.9, 1.4-16.8), coarctation of aorta (1.8, 1.1-3.0), esophageal atresia (2.3, 1.3-4.0), cloacal exstrophy (5.4, 1.6-19.3), craniosynostosis (1.9, 1.2-3.0) and omphalocele (2.2, 1.1-4.5).

CONCLUSIONS

Several associations between CC use and birth defects were observed. However, because of the small number of cases, inconsistency of some findings with previous reports, and the fact that we cannot assess the CC effect separately from that of the subfertility, these associations should be interpreted cautiously.

Sonographic measurements of the fetal fastigium between 20 and 40 weeks' gestation

OBJECTIVE

The purpose of this study was to establish a new reference angle chart for fastigial biometric measurements throughout gestation in normal singleton pregnancies.

METHODS

A prospective cohort study was designed. A total of 505 pregnant women between 20 and 40 weeks' gestation were included in the study. Excluded were those with multiple pregnancies, congenital anomalies, abnormal karyotypes, and polyhydramnios or oligohydramnios. Transvaginal or transabdominal sonography was performed in the midsagittal plane of the brain.

RESULTS

The angle of the fastigium was found to be 30 degrees to 60 degrees throughout pregnancy. These data were found to be constant during the progression of pregnancy without any significant changes.

CONCLUSIONS

Fastigial measurements throughout pregnancy are presented. Its angle is constant throughout pregnancy. Evaluation of the fastigium may assist in cases of subtle posterior fossa anomalies.

Developmental outcome of children with enlargement of the cisterna magna identified in utero

An enlarged cisterna magna can be identified during routine ultrasound screening in the second half of pregnancy. It is important to be able to give an accurate prognosis. We evaluated the developmental outcome of these children. A total of 29 fetuses with a large cisterna magna identified in utero were compared to 35 children with a normal fetal ultrasound. The children were evaluated by the Gesell Developmental Schedules and the Peabody Developmental Motor Scale. The study group showed a significantly worse performance in the Gesell test. However, the overall performance for both groups was within normal limits. Four children in the study group had a borderline developmental quotient. Both groups performed similarly in the Peabody test. Walking age was significantly delayed in the study group. Children with an enlarged cisterna magna may be at risk for mild developmental delay. In cases of nonisolated enlargement of the cisterna magna, the outcome may be guarded.

Neurodevelopmental outcomes in children with cerebellar malformations: a systematic review

Cerebellar malformations are increasingly diagnosed in the fetal period. Consequently, their consideration requires stressful and often critical decisions from both clinicians and families. This has resulted in an emergent need to understand better the impact of these early life lesions on child development. We performed a comprehensive literature search of studies describing neurodevelopmental outcomes of cerebellar malformations between January 1997 and December 2007. Overall, the data suggested that children with isolated inferior vermis hypoplasia (IVH) and mega cisterna magna (MCM) have a good developmental outcome, whereas children with molar tooth sign/Joubert syndrome, vermis hypoplasia, pontocerebellar hypoplasia (PCH) type II, and cerebellar agenesis experience moderate to severe global developmental delays. Reports for Dandy-Walker malformation (DWM) were conflicting; however, the presence of a normally lobulated vermis and the absence of associated brain anomalies were associated with a more favourable outcome. Finally, children with isolated cerebellar hypoplasia experienced fewer impairments. Important methodological limitations highlighted include a lack of standardized outcome measure use in 79% of studies and the predominant use of retrospective study designs (85%), with 40% limited to case reports or case-series. In summary, rigorous outcome studies describing the spectrum of disabilities in survivors are urgently needed to accurately delineate the long-term neurodevelopmental consequences of cerebellar malformations.

The Dandy-Walker variant: a case series of 24 pediatric patients and evaluation of associated anomalies, incidence of hydrocephalus, and developmental outcomes

OBJECT

The Dandy-Walker complex is a continuum of aberrant development of the posterior fossa that has been associated with multiple congenital anomalies, radiographic abnormalities, and developmental delay. The Dandy-Walker variant (DWV) is a unique entity believed to represent a milder form of the complex, and is characterized by a specific constellation of radiographic findings. In this retrospective case series, the authors report the association of the DWV with other congenital anomalies, the associated radiographic findings linked with DWV, and the developmental outcome in this population.

METHODS

The charts and radiographs of 10 male and 14 female patients treated between 2000 and 2006 were examined. The patients' mean gestational age was 35.6 weeks (range 23-41 weeks), and the mean follow-up period was 5.1 years (range 1 month-15 years).

RESULTS

Three patients died. Associated anomalies included cardiac (41.7%), neurological (33.3%), gastrointestinal (20.8%), orthopedic (12.5%), and genitourinary (12.5%) abnormalities. Less common were pulmonary and psychiatric findings. Developmental delay was identified in 11 of the 21 patients for whom follow-up was available. Five of 6 patients with isolated DWV had a normal developmental course. Radiographic findings associated with DWV included corpus callosum dysgenesis in 20.8%, ventricular enlargement in 29%, and vermian rotation in 8.3%. Shunts were placed in 4 of 7 patients with ventriculomegaly. Using the two-tailed Pearson correlation, the authors determined that developmental outcome was solely affected by neurological deficits and that ventricular enlargement predicted the need for shunt placement.

CONCLUSIONS

The DWV was associated with both extra- and intracranial anomalies. Associated radiographic abnormalities including ventriculomegaly were observed. Hydrocephalus requiring cerebrospinal fluid diversion may be indicated. Isolated DWV was associated with a good developmental outcome.

Clinical significance of isolated mega cisterna magna

OBJECTIVE

The prevalence and clinical significance of isolated mega cisterna magna in both fetuses and adults is not yet well defined. It is therefore difficult to provide reliable parental counseling in cases of a fetal sonographic diagnosis of this anomaly. The aim of the present study was to, determine the cognitive profile of adults with isolated mega cisterna magna.

METHODS

We reviewed 19,301 consecutive CT/MRI of the brain. Isolated mega cisterna magna was observed in 49 cases. A battery of neuropsychological tests was performed in 18 adults with this anomaly and in 18 controls who had no brain anomaly on CT/MRI.

RESULTS

Subjects with isolated mega cisterna magna had a lower performance on memory tasks [RAVLT saving score (0.8 +/- 0.2 vs. 1.02 +/- 0.2, P = 0.003)] and verbal fluency [phonemic fluency (9.4 +/- 4.5 vs. 13.6 +/- 5.3, P = 0.02), semantic fluency (19.8 +/- 5.8 vs. 24.4 +/- 7.5, P = 0.05)]. They did not differ from controls in regard to the Raven similarity tests indicating that this brain anomaly is not associated with impairment of general cognitive abilities.

CONCLUSION

Adults with isolated mega cisterna have an overall normal cognitive functioning but may score inferior to controls on some parameters of memory and verbal fluency. Although application of adult cases to the fetuses is not well established, this information might be of value in parental counseling in cases of a fetus with this anomaly.