Prenatal diagnosis of schizencephaly by fetal magnetic resonance imaging

Adult-Onset Seizure Disorder Secondary to Schizencephaly

Schizencephaly is a very rare neurological disorder usually discovered during radiological evaluation of children and young adults with seizure disorders or neurodevelopmental anomalies. We present a 66-year-old patient with right-sided hemiatrophy and paresis presenting with an adult-onset seizure disorder. Her seizure was satisfactorily controlled with a single-therapy antiseizure drug. Congenital brain lesions should be part of the differential diagnoses in patients with epilepsy who have body asymmetry dated back to childhood.

The Combined Use of Ultrasound and Fetal Magnetic Resonance Imaging for a Comprehensive Fetal Neurological Assessment in Fetal Congenital Cardiac Defects: Scientific Impact Paper No. 60

Heart problems are common in newborn babies, affecting approximately 5-10 in 1000 babies. Some are more serious than others, but most babies born with heart problems do not have other health issues. Of those babies who have a serious heart problem, almost 1 in 4 will have heart surgery in their first year. In the UK, pregnant women are offered a scan at around 20 weeks to try and spot any heart problems. In most cases there is not a clear reason for the problem, but sometimes other issues, such as genetic conditions, are discovered. In recent years the care given to these babies after they are born has improved their chances of surviving. However, it is recognised that babies born with heart problems have a risk of delays in their learning and development. This may be due to their medical condition, or as a result of surgery and complications after birth. In babies with heart problems, there is a need for more research on ultrasound and magnetic resonance imaging (MRI) to understand how the brain develops and why these babies are more likely to have delays in learning and development. This paper discusses the way ultrasound and MRI are used in assessing the baby's brain. Ultrasound is often used to spot any problems, looking at how the baby's brain develops in pregnancy. Advances in ultrasound technologies have made this easier. MRI is well-established and safe in pregnancy, and if problems in the brain have been seen on ultrasound, MRI may be used to look at these problems in more detail. While it is not always clear what unusual MRI findings can mean for the baby in the long term, increased understanding may mean parents can be given more information about possible outcomes for the baby and may help to improve the counselling they are offered before their baby's birth.

Complex Trajectories of Brain Development in the Healthy Human Fetus

This study characterizes global and hemispheric brain growth in healthy human fetuses during the second half of pregnancy using three-dimensional MRI techniques. We studied 166 healthy fetuses that underwent MRI between 18 and 39 completed weeks gestation. We created three-dimensional high-resolution reconstructions of the brain and calculated volumes for left and right cortical gray matter (CGM), fetal white matter (FWM), deep subcortical structures (DSS), and the cerebellum. We calculated the rate of growth for each tissue class according to gestational age and described patterns of hemispheric growth. Each brain region demonstrated major increases in volume during the second half of gestation, the most pronounced being the cerebellum (34-fold), followed by FWM (22-fold), CGM (21-fold), and DSS (10-fold). The left cerebellar hemisphere, CGM, and DSS had larger volumes early in gestation, but these equalized by term. It has been increasingly recognized that brain asymmetry evolves throughout the human life span. Advanced quantitative MRI provides noninvasive measurements of early structural asymmetry between the left and right fetal brain that may inform functional and behavioral laterality differences seen in children and young adulthood.

Imaging of congenital Zika virus infection: the route to identification of prognostic factors

Zika virus (ZIKV) has recently emerged as a novel teratogenic agent associated with severe neurological complications. The risk associated with maternal infection remains to be exactly defined but appears to be significant. Like other TORCH agents (toxoplasmosis, other agents, rubella, cytomegalovirus and herpes simplex), it is unlikely that all affected fetuses will be symptomatic at birth. It is therefore urgent to better define the spectrum of anomalies observed in infected fetuses to provide adequate parental counseling. In this review, we provide a comprehensive analysis of major cases described to date and highlight specific prenatal and postnatal radiological findings of congenital ZIKV infection. A total of 19 reports were included in our analysis. ZIKV seemed to harbor a specific tropism for the central nervous system, and anomalies were mostly limited to the brain. Major radiological findings were ventriculomegaly, diffuse calcifications and signs of abnormal gyration as well as cortical development. In addition, a significant number of fetuses suffered from intra uterine growth restriction. Based on these findings, we provide recommendations for adequate radiological monitoring of at-risk pregnancies. © 2016 John Wiley & Sons, Ltd.

Prenatal Diagnosis and Postnatal Outcome of Schizencephaly

The aim of this study was to present our experience with 5 cases of fetal schizencephaly in terms of prenatal diagnostic features, and postnatal outcome. The database of prenatal diagnosis unit was searched for antenatally diagnosed cases with schizencephaly. Maternal characteristics, ultrasonography, prenatal-postnatal magnetic resonance imaging (MRI) findings, and postnatal outcome were noted. Of 5 cases, 2 had definitive prenatal diagnoses on ultrasound and 3 cases were diagnosed by fetal MRI. All cases had cerebral cortical migration anomalies including polymicrogyria, subependymal heterotopia, and lissencephaly, and 2 cases had additional extracranial malformations. Three cases showed regression of the cerebral clefts on follow-up postnatal MRIs. Three cases had moderate to severe psychomotor retardation, and 1 case needed repeated ventriculoperitoneal shunt operation due to hydrocephaly. Prenatal diagnosis of schizencephaly with ultrasonography is not straightforward and required further evaluation with fetal MRI. Additional cerebral anomalies worsen the prognosis of schizencephaly.

Clinical and radiologic features of unilateral and bilateral schizencephaly in polish pediatric patients

Schizencephaly is a rare and severe congenital brain defect. Its etiology is not unequivocal and its clinical course differs with every case. The aim of the study was to analyze correlations between clinical and radiologic features of schizencephaly in Polish patients. The study group consisted of 25 children. Epileptic seizures were observed in 60% of cases and in 32% epilepsy was drug resistant. Generalized hypotonia was found in 24%, spastic diparesis in 48%, and spastic hemiparesis in 28% of cases. Seizures were more frequent in the bilateral than unilateral schizencephaly subgroup (72% vs 29%, P = .045). There was a correlation between the presence of the bilateral type II schizencephaly and the occurrence of seizures (P = .002, r = 0.578). There is a correlation between the type of schizencephaly and the presence of seizures in Polish pediatric patients. In most of the patients, schizencephaly leads to developmental retardation and epileptic seizures.

Correlation of prenatal and postnatal MRI findings in schizencephaly

BACKGROUND AND PURPOSE

Schizencephaly is a rare malformation of the brain characterized by a gray matter-lined defect extending from the pial surface to the lateral ventricles. The purpose of this study was to correlate imaging findings of schizencephaly and associated anomalies on fetal and postnatal MR imaging and assess possible changes that may occur from the prenatal-to-postnatal state.

MATERIALS AND METHODS

A retrospective review of subjects with schizencephaly who had both pre- and postnatal MR imaging was performed. Subject age, cleft type, number, location, and features of the defects and associated anomalies were recorded. Normalized dimensions of the defect and ipsilateral ventricle were measured and correlated to changes in the clefts between pre- and postnatal imaging.

RESULTS

Ten subjects with 18 clefts (8 bilateral) were included. Most defects (83%) were open on prenatal MR imaging, but 47% of those were found to have subsequently closed on postnatal imaging. Evidence of prior hemorrhage was seen in 83%. Prenatal MR imaging detected all cases of an absent septum pellucidum but detected a fraction of gross polymicrogyria and missed all cases of optic nerve hypoplasia. The normalized ipsilateral ventricular and inner and middle width dimensions of the defects were significantly decreased at postnatal imaging (P < .05). The widths of the defects, ventricular width, and presence of hemorrhage were not predictors of closure of prenatally diagnosed open defects (P > .05).

CONCLUSIONS

In our series, nearly half of prenatally open schizencephaly defects had closed on postnatal imaging. Prenatal MR imaging was only able to demonstrate some of the associated anomalies.

Unilateral Type II Schizencephaly

Schizencephaly is a rare developmental disorder of the brain that is characterized by abnormal clefts within the cerebral hemispheres. Infants with this disorder commonly have developmental delay, delay in speech and language, partial or complete paralysis, poor muscle tone, and seizures. The manifestations and severity of the disease are related to the size and location of the clefts. The authors report a case of type II (open-lipped) schizencephaly diagnosed in the second trimester by sonography. Early prenatal diagnosis of fetal type II (open-lipped) schizencephaly allows time for patient counseling and discussion of options and preparation.

Fetal opercular cavernous angioma causing cerebral cleft: contralateral primitive vascular anomaly and subicular dysgenesis

We describe a 22-week female fetus after pregnancy was terminated because of fetal magnetic resonance imaging showing a large left cerebral hemispheric cleft suggestive of porencephaly or schizencephaly. Postmortem examination revealed a large cavernous angioma of the left opercular region with evidence of previous hemorrhage and extensive cerebral infarction. In the right hemisphere, another vascular malformation within the frontal germinal matrix consisted of an aggregate of primitive vessels not yet canalized. Selective dysgenesis of the right subiculum also was demonstrated. This case illustrates not only a severe encephaloclastic effect of cavernous angioma in fetal brain but also the importance of fetal autopsy to help correlate and explain fetal neuroimaging. Potential future prenatal treatment of fetal angiomata requires precise in utero diagnosis.

Fetal neuroimaging

Although ultrasound remains the screening modality of choice in evaluation of the fetal nervous system, magnetic resonance imaging with its multiplanar imaging ability and high signal-to-noise ratio is highly accurate in illustrating the morphologic changes of the developing brain and fetal brain abnormalities. Fetal magnetic resonance imaging is an established powerful tool for obtaining additional information in evaluation of anomalies of the fetal face, neck, and spine. It is helpful to patients and their health care professionals in making vital management decisions and aids in genetic counseling for future pregnancies.

Schizencephaly: pre- and postnatal magnetic resonance imaging

Schizencephaly is a rare disorder of neuronal migration that is characterized by the presence of clefts that extend from the ependymal surface of the lateral ventricles to the pial lining of the cortex. The authors present the case of a female patient with a prenatal diagnosis made by magnetic resonance imaging (MRI), her clinical course, and neurorradiological evolution following birth. A 6-year-old female, with right open lip schizencephaly, was diagnosed by means of prenatal cerebral magnetic resonance at the gestational age of 25 weeks. The patient does not present intellectual disability, reaching developmental mile-stones at normal time points. The MRI of the brain reveals right, perisylvian, closed lip schizencephaly. Prenatal MRI is remarkably useful in the diagnosis and prognostic approach to the condition. It is less useful in classifying the unilateral forms (open vs closed lips), and hence, its prognostic validity is more limited.

Abnormalities of the foetal cerebral cortex

Prenatal ultrasound has concentrated on readily visible cerebral structures including head size, shape, ventricles, CSP (cavum septi pellucidi), cerebellar size/vermian presence and cisterna magna. However, apart from these easily visible structures it is important to evaluate the brain itself. Patients who initially appear to have mild isolated findings such as borderline ventriculomegaly in fact can have many more subtle findings that significantly alter prognosis and management that can be detected on detailed examination of the brain. There has been rapid evolution in imaging these foetuses, especially with neurosonography and MRI, and a revolution in understanding the underlying genetic and biochemical mechanisms. There is increasing emphasis to detect cortical abnormalities as early as possible. This article reviews development of the cerebral cortex, the classification, aetiologies and clinical manifestations of cortical disorders, normal and abnormal appearances at ultrasound and MRI, and approaches to investigation.

Patient safety issues in magnetic resonance imaging: state of the art

The presence of a static magnetic field (Bo), a radiofrequency field (RF), a dynamic gradient which varies in time and loud noises during an MR examination could increase patient risk. Specifically, a magnetic field could interfere with ferromagnetic material leading to one of the following five dangerous interactions: 1) projectile effect, 2) twisting, 3) burning, 4) artefacts and 5) device malfunction. The projectile effect is when an object is attracted by the magnet with the risk, as reported in literature, of hitting the patient, operators and/or the instrument. Objects which typically can undergo this effect are oxygen and helium cylinders, IV stands, cleaning trolleys, chairs, lamp holders, scissors, forceps, clampers, traction weights, monitoring instruments, and especially metallic splinters within the patient. Twisting (torsion) typically occurs with cerebral vascular clamps and cochlear implants. If parts of implants are involved a malfunction may result. Burns can be caused when electrically conductive material is introduced within the magnet, for example, ECG electrodes, monitoring cables and coils which are in contact with the patient's skin, as well as tattoos and eye-liners that contain iron-oxides. Artefacts can be induced by RF emission of implanted devices which can be mistaken for noise of the receiving coil. Implanted devices can induce signal voids which mask or simulate pathologies. Electrical or mechanical malfunction of implanted devices includes pacemakers which can stimulate inappropriately or at an elevated frequency yielding a distorted ECG with altered T-waves. The risk for patients can be reduced by specific educational programs within individual radiology departments which include other specializations and external referring physicians with the aim of developing a standardized safety protocol.

Prenatal diagnosis of malformations of cortical development by dedicated neurosonography

OBJECTIVE

Malformations of cortical development (MCD) are rarely diagnosed in utero. We describe and compare the ultrasonographic and pathology findings in a cohort of fetuses with MCD.

METHODS

Fetuses with MCD were identified among all fetuses evaluated for suspected brain anomalies at the Fetal Neurology Clinic, and the ultrasonographic findings were compared with the results of the pathology examination.

RESULTS

We suspected the presence of MCD by ultrasonography in 23 fetuses. The mean gestational age at the time of ultrasound diagnosis was 26.2 (range, 18-40) weeks. The ultrasonographic findings leading to the diagnosis of MCD were abnormally overdeveloped gyri and sulci for gestational age (n = 7), delay in sulcation (n = 5), abnormally thin cortex (n = 5) abnormally wide and broad sulci (n = 3), bulging into the lateral ventricle (n = 1), cortical cleft (n = 1), and multiple intraparenchymal echogenic nodules (n = 1). All fetuses had associated central nervous system (CNS) and/or non-CNS anomalies. Pathology examination (performed in 17 fetuses) confirmed MCD in 16.

CONCLUSIONS

Cortical malformations can be diagnosed in utero by ultrasonography based on the presence of specific deviations from the normal pattern of development. The identified cases may represent the more severe forms in the MCD spectrum. The pathology findings do not always conform to the current classification systems of MCD but help in differentiating between possible genetic and acquired etiologies and in some cases provide a definitive syndromic diagnosis.

Fetal schizencephaly: pre- and postnatal imaging with a review of the clinical manifestations

Schizencephaly is a rare malformation of the central nervous system. Prenatal ultrasound (US) allows diagnosis of schizencephaly, although prenatal magnetic resonance (MR) imaging is even more specific in detection of gray matter lining the defect, communication with the ventricle, and other associated structural abnormalities. Six cases of schizencephaly were evaluated at one institution; prenatal US was performed in all cases, and fetal MR imaging was performed in three cases. As with many malformations, more severe cases of schizencephaly often manifest in utero. All of the cases studied were of the open-lip variety; three cases were bilateral, and three were unilateral. The cleft was not appreciated at initial US in only one case, which consisted of a small unilateral defect, with the diagnosis made at subsequent MR imaging. A survey of the clinical literature on schizencephaly shows that the severity of the motor and mental impairments is directly related to the extent of the anatomic defect. The differential diagnosis for a cerebrospinal fluid-containing abnormality of the fetal brain includes both developmental and destructive lesions. Prenatal detection of schizencephaly can assist in management of the pregnancy.

A review of the current use of magnetic resonance imaging in pregnancy and safety implications for the fetus

This paper presents an overview of the application of and risks of exposure to Magnetic Resonance Imaging (MRI) in pregnancy. It reviews the risks to the fetus by considering the hazards in terms of the three main components of an MRI system. These are the static magnetic field, the time-varying magnetic gradient fields and the pulsed radio frequency fields. The hazards discussed are biological effects, miscarriage, heating effects and acoustic noise exposure. This paper also presents a survey of MRI sites within the United Kingdom to ascertain the extent of MRI usage in pregnancy. To validate the situation of MRI in pregnancy a survey was sent to 352 MR units throughout the United Kingdom. The questions were grouped to assess (a) maternal MRI diagnosis (b) fetal MRI and (c) work practices for pregnant MRI staff. The results showed that 91% of sites were imaging pregnant women in need of diagnosis in the second and third trimester. This paper highlights that MRI can add information for fetal central nervous system abnormalities identified by ultrasound screening, however within the UK direct fetal imaging was only performed in 8% of sites. This paper indicates the need for research to be undertaken for specific MRI clinical conditions. It also advises that risk assessment for pregnant staff working in MRI is performed, and that there is a clear need for further research into the effects of MRI in pregnancy as there is a need for clear authoritive advice.

EMX2-independent familial schizencephaly: Clinical and genetic analyses

Schizencephaly is a human brain malformation distinguished by full-thickness unilateral or bilateral clefts through the neocortex. Heterozygous mutations in the EMX2 locus are reported to give rise to schizencephaly. However, the comprehensive identification of causative genetic loci is precluded by a lack of large pedigrees and genome-wide linkage analyses. We present here a large Turkish pedigree with three individuals with schizencephaly. The similarity of clinical signs in affected individuals strongly suggests an underlying genetic cause; however, genome-wide linkage analysis rules out EMX2 linkage and instead suggests additional candidate loci. These results indicate that genetic forms of schizencephaly are likely to be heterogeneous.

Fetal imaging of central nervous system abnormalities

Fetal MR imaging is complementary to obstetric ultrasonography. The additional information provided by in utero MR imaging may alter prenatal, perinatal, or immediate postnatal management. For example, the MR imaging findings may affect the decision to continue the pregnancy, change the mode, timing, or location of delivery, or modify decisions regarding the necessity of immediate postnatal surgery. Finally, the information contributed by MR may permit a better assessment of the risk of recurrent defects in subsequent pregnancies.

Ultrafast fetal MRI and prenatal diagnosis

Improvements in magnetic resonance imaging (MRI) technology continue to provide faster scan times and higher resolution increasing the applications for fetal imaging. MRI is an adjunct to good prenatal ultrasound scan (US). It provides significant additional information that improves diagnostic accuracy in evaluation of the fetal brain, spine, neck, chest, abdomen, and urinary tract. MRI provides important anatomic information that helps in planning delivery and surgical procedures.