Prenatal Imaging of Congenital Malformations of the Brain

Unraveling Dandy-Walker Malformation: A Comprehensive Literature Review and Case Insight

Dandy-Walker spectrum disorder (DWSD) is a congenital abnormality of the brain, consisting typically of partial or complete hypoplasia of the cerebellar vermis, cystic dilation of the fourth ventricle, and enlargement of the posterior fossa. Approximately 1 in 10,000 to 30,000 live births is affected by this typically early-onset neurological condition, which commonly presents with hydrocephalus, irritability, and poor motor coordination. Usually, the diagnosis is confirmed by anatomic features typical of computed tomography or magnetic resonance imaging (MRI). Management has been largely hydrocephalus-oriented, usually by VP shunting and multidisciplinary follow-up for neurological and developmental improvement in the long run. Herein is reported a case with a 5-month-old male presenting with DWSD, which has been documented in this paper along with his clinical presentation, imaging findings, and, most importantly, the response to the cerebrospinal fluid (CSF) diversion following the shunt. This case highlights the importance of early intervention, early comprehensive imaging, and a multidisciplinary approach, including genetic counseling, in optimizing the quality of life and managing complex developmental needs associated with DWSD.

Advancing fetal diagnosis and prognostication using comprehensive prenatal phenotyping and genetic testing

Prenatal diagnoses of congenital malformations have increased significantly in recent years with use of high-resolution prenatal imaging. Despite more precise radiological diagnoses, discussions with expectant parents remain challenging because congenital malformations are associated with a wide spectrum of outcomes. Comprehensive prenatal genetic testing has become an essential tool that improves the accuracy of prognostication. Testing strategies include chromosomal microarray, exome sequencing, and genome sequencing. The diagnostic yield varies depending on the specific malformations, severity of the abnormalities, and multi-organ involvement. The utility of prenatal genetic diagnosis includes increased diagnostic clarity for clinicians and families, informed pregnancy decision-making, neonatal care planning, and reproductive planning. Turnaround time for results of comprehensive genetic testing remains a barrier, especially for parents that are decision-making, although this has improved over time. Uncertainty inherent to many genetic testing results is a challenge. Appropriate genetic counseling is essential for parents to understand the diagnosis and prognosis and to make informed decisions. Recent research has investigated the yield of exome or genome sequencing in structurally normal fetuses, both with non-invasive screening methods and invasive diagnostic testing; the prenatal diagnostic community must evaluate and analyze the significant ethical considerations associated with this practice prior to generalizing its use. IMPACT: Reviews available genetic testing options during the prenatal period in detail. Discusses the impact of prenatal genetic testing on care using case-based examples. Consolidates the current literature on the yield of genetic testing for prenatal diagnosis of congenital malformations.

Dandy-Walker malformation associated with subarachnoid hemorrhage. A case report

INTRODUCTION

Dandy-Walker malformation is a rare congenital brain defect characterized by vermian agenesia with cystic dilatation of the fourth ventricle, and posterior fossa enlargement. The etiology is still poorly understood but is presupposed to be multifactorial, infrequently caused by intracranial hemorrhage. We describe a case of male newborn known to have Dandy-Walker malformation associated with subarachnoid bleeding after the delivery, which is a quiet rare presentation only discussed in a few literatures before.

CASE PRESENTATION

We present a rare case of a full-term male baby delivered vaginally, who was diagnosed with Dandy-Walker malformation during antenatal anomaly scan. At birth, the baby presented with a weak cry, cyanosis, respiratory distress and seizure. Post-delivery computed tomography scan revealed subarachnoid hemorrhage. In addition, a hydrocephalus was noted on the imaging and treated with ventriculoperitoneal shunt insertion with marked improvement of the posterior fossa cyst and the hydrocephalus as an outcome of early intervention.

DISCUSSION

Few literature studies showed an association between intracranial bleeding during early fetal life and the development of Dandy-Walker malformation as it affects the posterior fossa components growth. However, our case highlights on an unusual presentation of the spontaneous subarachnoid hemorrhage after the delivery in a full-term baby diagnosed with Dandy-Walker malformation earlier.

CONCLUSION

This report highlights the importance of early recognition and implementing appropriate management of the hydrocephalus that associated with intracerebral bleeding to prevent the complications of high intracranial pressure plus brainstem herniation and achieve the best possible outcome.

Dandy-Walker Malformation With Hydrocephalus: Diagnosis and Its Treatment

Dandy-Walker malformation is an uncommon type of brain malformation that occurs during embryonic development of the cerebellum and fourth ventricle. A case of Dandy-Walker malformation with hydrocephalus is being elaborated. The patient was operated on by the neurosurgery department and underwent ventriculoperitoneal shunting. The patient was stable and improved during the postoperative period.

A comparison of Adult and Pediatric Hydrocephalus

Hydrocephalus is a common clinical problem encountered in neurosurgical practice. With greater subspecialisation, pediatric neurosurgery has emerged as a special discipline in several countries. However, in the developing world, which inhabits a large pediatric population, a limited number of neurosurgeons manage all types of hydrocephalus across all ages. There are some essential differences in pediatric and adult hydrocephalus. The spectrum of hydrocephalus of dysgenetic origin in a neonate and that of normal pressure hydrocephalus of the old age has a completely different strategy of management. Endoscopic third ventriculostomy outcomes are known to be closely associated with age at presentation and surgery. Efficacy of alternative pathways of CSF absorption also differs according to age. Managing this disease in various age groups is challenging because of these differences in etiopathology, tempo of the disease, modalities of investigations and various treatment protocols as well as prognosis.

Dandy-Walker syndrome with bilateral choanal atresia: A case report

INTRODUCTION

Dandy-Walker syndrome is a rare congenital brain malformation characterized by cerebellar vermis agenesis or hypoplasia, cystic dilatation of the fourth ventricle and a large posterior fossa causing upward displacement of tentorium and torcula. In this paper, we present a case of bilateral choanal atresia with Dandy-Walker Syndrome in a female newborn.

CASE PRESENTATION

We present a case of a female patient who was born at 38th weeks of gestation via emergency cesarean section due to non-reassuring cardiotocography and abnormal antenatal ultrasounds findings. The imaging revealed the presence of Dandy-walker malformation. The patient presented with cyanosis and respiratory distress. Bedside flexible nasoendoscopy revealed bilateral choanal atresia which is confirmed by computed tomography of sinuses. Endoscopic bilateral choanal atresia repair was performed. On postoperative follow up, nasal endoscopy showed bilateral intact flap and patent neochoana.

DISCUSSION AND CONCLUSION

Dandy-Walker syndrome is a congenital disorder that can be diagnosed prenatally. The syndrome is associated with multiple anomalies. However, there are few published reports of bilateral choanal atresia in Dandy-Walker Syndrome. Bilateral choanal atresia is considered a life-threatening condition in newborns that requires early surgical intervention.

Prenatal sonographic diagnosis of Dandy-Walker malformation and type III lissencephaly: A novel association

Dandy-Walker malformation (DWM) may occur as part of Mendelian disorders such as Walker-Warburg and Meckel-Gruber syndromes. We report a novel association with type III lissencephaly in a 22-week male fetus. Ultrasound showed fetal akinesia deformation sequence, single umbilical artery, microlissencephaly, hydranencephaly with cerebral lamination, DWM, and pontocerebellar hypoplasia. These abnormalities were confirmed by magnetic resonance imaging and autopsy, which also revealed pulmonary and adrenal hypoplasia, common mesentery and bilateral uretero-pyelo-calyceal dilatation. Neuropathological examination showed brain calcifications and diffuse neuronal degeneration. We conclude that DWM may be a feature of type III lissencephaly and that this association can be easily diagnosed by ultrasound.

Prenatal or Perinatal Injury? Diagnosing the Cortically Blind Infant

PURPOSE

To document the association of prenatal brain disruption with secondary perinatal distress in children diagnosed as having cortical visual impairment (CVI).

DESIGN

Retrospective case series.

METHODS

Eight children with severe CVI and clinical history of perinatal events were included. Case histories and neuroimaging studies were reviewed. The main outcome measures were perinatal history, visual and neurologic findings, and magnetic resonance (MR) imaging.

RESULTS

In our patient cohort, MR imaging showed signs of cortical dysgenesis leading to congenital brain malformations such as polymicrogyria consistent with a prenatal timing of CNS injury. Although subcortical white matter changes were common, signs of watershed injury to the visual cortex were absent, suggesting that the visual loss was attributable to a prenatal etiology with secondary birth complications.

CONCLUSION

Some children with CVI and a history of perinatal distress have prenatal dysgenesis of the developing brain. Therefore, a clinical history of perinatal hypoxia-ischemia is nonspecific and merits neuroimaging to identify antecedent brain malformations and timing of injury, which can influence patient diagnosis and management.

Brain Malformations at All Ages: From Aunt Minnie to Zebras for General Radiologists

Congenital brain malformations comprise a spectrum of disorders that result from a variety of causes, including genetic abnormalities, ischemia, infections, and toxic exposures. Although most cases are discovered in infancy or childhood, clinically occult abnormalities may prove to be confounding, especially if first encountered later in life on imaging examinations obtained for other indications or in the context of superimposed pathology. This review article provides an overview of congenital brain malformations because they may be encountered at all ages for general radiologists.

5-year experience of a tertiary center in major congenital abnormalities in singleton pregnancies

OBJECTIVE

To demonstrate major congenital abnormalities delivered or terminated at our institution between 2014 and 2018.

MATERIALS AND METHODS

Necessary information was retrieved from the registries of the delivery room and electronic database of Hacettepe University Hospital, Ankara.

RESULTS

This study was consisted of 307 major congenital anomalies. The incidence of major congenital anomalies was 2.9 per 1,000 live births, while the majority of the cases were related to cardiovascular, central nervous system, and diaphragmatic hernia with 97, 87, and 25 cases at each group, respectively. Rate of termination of pregnancy (TOP) and live birth were 35.1 and 59.2%, respectively. The overall infant mortality rate was 28.9% in cases with live birth, while this rate was highest in cardiovascular system abnormalities and diaphragmatic hernia. Out of 182 newborns, 92.8% admitted to the neonatal intensive care unit after the delivery. Median gestational week at TOP was 21(20).

CONCLUSION

We have shown that TOP and infant mortality rates were 35.1 and 28.9%, respectively in pregnancies with fetal malformations. Detailed multidisciplinary counseling must be provided for parents in pregnancies with major congenital abnormalities.

[Disorders of migration and gyration]

Disorders of migration and gyration are a versatile group of pathologies that may cause epilepsy and/or neurodevelopmental delay. With the recent improvement of imaging methods, it is possible to detect these pathologies, not only on postnatal MRI but also in utero using fetal MRI. The use of MRI together with genetic tests and knowledge of the classification of these malformations makes early diagnosis possible. Furthermore, the exact diagnosis of disorders of gyration and migration will help ensure better treatment of symptomatic epilepsies as well as be of great help in counselling the parents if detected in utero. Ultimately, it may enable the development of new treatment strategies. Therefore, in this review the fetal neuroanatomy and pathologies due to migration and abnormal postmigratory processes together with the recent classification of these malformations are elucidated, which will ensure early diagnosis of these types of developmental disorders.

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

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

Evaluation of Subependymal Gray Matter Heterotopias on Fetal MRI

BACKGROUND AND PURPOSE

Subependymal grey matter heterotopias are seen in a high proportion of children with Chiari II malformation and are potentially clinically relevant. However, despite its growing use, there is little in the literature describing its detection on fetal MRI. Our aim was to evaluate the accuracy in diagnosing subependymal gray matter heterotopias in fetuses with spinal dysraphism on fetal MR imaging.

MATERIALS AND METHODS

This study is a retrospective analysis of 203 fetal MRIs performed at a single institution for spinal dysraphism during a 10-year period. Corresponding obstetric sonography, postnatal imaging, and clinical/operative reports were reviewed.

RESULTS

Of the fetal MRIs reviewed, 95 fetuses were included in our analysis; 23.2% (22/95) were suspected of having subependymal gray matter heterotopias on fetal MR imaging prospectively. However, only 50% (11/22) of these cases were confirmed on postnatal brain MR imaging. On postnatal brain MR imaging, 28.4% (27/95) demonstrated imaging findings consistent with subependymal gray matter heterotopia. Only 40.7% (11/27) of these cases were prospectively diagnosed on fetal MR imaging.

CONCLUSIONS

Fetal MR imaging is limited in its ability to identify subependymal gray matter heterotopias in fetuses with spinal dysraphism. It is believed that this limitation relates to a combination of factors, including artifacts from fetal motion, the very small size of fetal neuroanatomy, differences in imaging techniques, and, possibly, irregularity related to denudation of the ependyma/subependyma in the presence of spinal dysraphism and/or stretching of the germinal matrix in ventriculomegaly.

[Fetal MRI and ultrasound of congenital CNS anomalies]

In the last decade the newest technologies, fetal magnetic resonance imaging (MRI) and 3D ultrasound, have given an insight into the minute structures of the fetal brain. However, without knowledge of the basic developmental processes the imaging is futile. Knowledge of fetal neuroanatomy corresponding to the gestational week is necessary in order to recognize pathological structures. Furthermore, a modern neuroradiologist should be acquainted with the three steps in the formation of the cerebral cortex: proliferation, migration and differentiation of neurons in order to be in a position to suspect that there is a pathology and start recognizing and discovering the abnormalities. The fetal MRI has become an important complementary method to ultrasound especially in cortical malformations when confirmation of the prenatal diagnosis is needed and additional pathologies need to be diagnosed. In this manner these two methods help in parental counseling and treatment planning.

Prenatal and Postnatal Schizencephaly Findings by 2D and 3D Ultrasound: Pictorial Essay

Schizencephaly is a brain-destructive lesion relating to clefts in the fetal brain that usually communicate with the ventricular system, subarachnoid space, or both. It presents as two types: Type I (closed) and Type II (open). During pregnancy, it may be suspected in the course of ultrasonography, which highlights ventricular dilatation and brain abnormalities. Usually, the diagnosis is confirmed postnatally using trans-fontanel ultrasonography. The etiology of schizencephaly is still unknown, but it may be derived from a primary disorder of brain development or from bilateral middle cerebral artery occlusion. Many causative agents including vascular insult, infections, toxins, and medications have been associated with this malformation. We present a pictorial essay of six cases of schizencephaly that were suspected on prenatal ultrasound scans and confirmed postnatally by trans-fontanel, two-dimensional and three-dimensional ultrasonography.