Disorders of cortical formation: MR imaging features

The molecular genetics of PI3K/PTEN/AKT/mTOR pathway in the malformations of cortical development

Malformations of cortical development (MCD) are a group of developmental disorders characterized by abnormal cortical structures caused by genetic or harmful environmental factors. Many kinds of MCD are caused by genetic variation. MCD is the common cause of intellectual disability and intractable epilepsy. With rapid advances in imaging and sequencing technologies, the diagnostic rate of MCD has been increasing, and many potential genes causing MCD have been successively identified. However, the high genetic heterogeneity of MCD makes it challenging to understand the molecular pathogenesis of MCD and to identify effective targeted drugs. Thus, in this review, we outline important events of cortical development. Then we illustrate the progress of molecular genetic studies about MCD focusing on the PI3K/PTEN/AKT/mTOR pathway. Finally, we briefly discuss the diagnostic methods, disease models, and therapeutic strategies for MCD. The information will facilitate further research on MCD. Understanding the role of the PI3K/PTEN/AKT/mTOR pathway in MCD could lead to a novel strategy for treating MCD-related diseases.

Double Cortex Syndrome: An Unusual Cause of Seizures

Gray matter heterotopia (GMH) is caused by abnormal neuronal migration during brain development. Subcortical band heterotopia (SBH), or double cortex, is a rare variant of GMH that mainly affects female patients with epilepsy (PWE) with different degrees of mental retardation. We present the case of a 25-year-old woman who was admitted to the neurology department of our tertiary hospital with generalized tonic-clonic seizures. Her mother had a normal antenatal period and a history of labor. There was a history of immediate crying and normal appearance, pulse, grimace, activity, and respiration (APGAR) scores. She had delayed milestones, which affected various categories of child development. Physical examination revealed a global developmental delay. Laboratory values, including complete blood count, serum calcium, and arterial blood gas tests, were all within normal limits. An EEG showed significant abnormalities suggestive of epilepsy. An MRI of the brain showed a continuous band of gray matter located deep and parallel to the cortex in both cerebral hemispheres, suggesting double cortex syndrome (DCS).

Cortical malformation adjacent to a large pial arteriovenous fistula

The coexistence of an arteriovenous fistula (AVF) and neuronal migration abnormalities is a rare phenomenon. The underlying pathophysiology responsible for these anomalies remains elusive. Neuronal architectural irregularities arise from complex neuronal formation, migration and organisation dysfunctions. Isolated cases of these associations are rarely described in the literature. Here, we present an unusual case involving the coexistence of a pial AVF and a pachygyria-polymicrogyria complex in an early childhood boy. We have provided a detailed description of the neuroimaging characteristics and the therapeutic embolisation in this case, along with follow-up. Additionally, we conduct a comprehensive review of potential hypotheses about the association, referencing prior case reports. The presence of an aberrant blood supply or deviant venous drainage from the developing cortex may contribute to a variety of neuronal migration anomalies.

Imaging Features of Ectopic Tissues and Their Complications: Embryologic and Anatomic Approach

Ectopic tissue is an anatomic abnormality in which tissue develops in an area outside its normal location. It is primarily caused by abnormalities during the process of embryologic development. Although the majority of individuals with ectopic tissues remain asymptomatic, various symptoms and associated complications can occur. Failure in normal embryologic development leads to loss of normal physiologic function or may result in harmful functions such as ectopic hormonal secretion in the ectopic pituitary adenoma. Ectopic tissues may also frequently mimic tumors. For example, developmental abnormalities in the pharyngeal pouches may result in an ectopic parathyroid gland and ectopic thymus, both of which are frequently misdiagnosed as tumors. Adequate knowledge of embryology is essential for understanding the differential diagnoses of ectopic tissues and facilitating appropriate management. The authors summarize the embryologic development and pathogenesis of ectopic tissues by using illustrations to facilitate a deeper understanding of embryologic development and anatomy. Characteristic imaging findings (US, CT, MRI, and scintigraphy) are described for ectopic tissues of the brain, head, neck, thorax, abdomen, and pelvis by focusing on common conditions that radiologists may encounter in daily practice and their differential diagnoses. ^©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Dyke-Davidoff-Masson Syndrome: A Classic Case Report

Dyke-Davidoff-Masson syndrome (DDMS) is a rare neurological disorder found in children as well as adults. It is characterized by hemi cerebral atrophy. To date, very few cases of this disorder have been reported. Radiological imaging including magnetic resonance imaging (MRI) and computed tomography (CT) are accurate tools for the diagnosis of DDMS. We present a case of a 13-year-old female child who came with complaints of multiple episodes of generalized tonic-clonic seizures. In our case, clinical history and imaging with CT and MRI were accurate enough to diagnose DDMS.

Malformation of the Cortical Development Associated with Severe Clusters of Epileptic Seizures

Three cases of the malformation of the cortical development are described: a mixed breed dog and a Border Collie pup with a focal and diffuse cortical dysplasia, respectively, and a kitten with lissencephaly. All cases presented with intractable epilepsy and were euthanized, due to the cluster of epileptic seizures. The gross examination at necropsy revealed the morphologic alteration of the telencephalic region in two cases. Histopathologically, a disorganization of the cortical lamination with the presence of megalic neurons, was found in the focal cortical dysplasia case. An altered organization of the white and gray matter, with a loss of the normal neuronal distribution and altered neurons, characterized the diffuse cortical dysplasia case. In the lissencephalic cat, there was no recognizable organization of the brain with areas of neuroglial tissue forming nodules in the leptomeningeal space. We strongly support the hypothesis that, as in humans, as well as in the veterinary patients, malformations of the cortical development could be the cause of refractory epilepsy.

Orchestrating human neocortex development across the scales; from micro to macro

How our brains have developed to perform the many complex functions that make us human has long remained a question of great interest. Over the last few decades, many scientists from a wide range of fields have tried to answer this question by aiming to uncover the mechanisms that regulate the development of the human neocortex. They have approached this on different scales, focusing microscopically on individual cells all the way up to macroscopically imaging entire brains within living patients. In this review we will summarise these key findings and how they fit together.

Imaging of Congenital Malformations of the Brain

Brain formation is a continuous and complicated process that is historically categorized by the timing of development. The earliest disorders of dorsal induction occur in the first month of gestation and include anencephaly and cephalocele. Disorders of ventral induction occur during the second month of gestation and include the holoprosencephaly and septo-optic dysplasia spectrums. The third and longest timeframe include the disorders of neuronal migration and proliferation (gestational weeks eight-25) and include malformations of cortical development: lissencephaly, polymicrogyria, schizencephaly, gray matter heterotopia, and corpus callosal dysgenesis. This review will highlight the neuroimaging of these malformations.

The changing landscape in epilepsy imaging: Unmasking subtle and unique entities

Dramatic changes have occurred recently in the field of epilepsy, including a fundamental shift in the etiology of epileptogenic substrates found at surgery. Hippocampal sclerosis is no longer the most common etiology found at epilepsy surgery and this decrease has been associated with an increase in the incidence of focal cortical dysplasia and encephaloceles. Significant advances have been made in molecular biology and genetics underlying the basis of malformations of cortical development, and our ability to detect epileptogenic abnormalities with MR imaging has markedly improved. This article begins with a discussion of these trends and reviews imaging techniques essential for detecting of subtle epilepsy findings. Representative examples of subtle imaging findings are presented, which are often overlooked but should not be missed. These include temporal lobe encephaloceles, malformations of cortical development (and especially focal cortical dysplasia), hippocampal sclerosis, hippocampal malformation (also known as HIMAL), ulegyria, autoimmune encephalitis, and Rasmussen's encephalitis. Recent findings on the pathophysiology and genetic underpinnings of several causes of localization-related epilepsy are incorporated. For instance, it has been recently found that focal cortical dysplasia IIb, tuberous sclerosis, hemimegalencephaly, and gangliogliomas are all the result of mutations of the mTOR pathway for cell growth.

A hierarchical anatomical framework and workflow for organizing stereotactic encephalography in epilepsy

Stereotactic electroencephalography (SEEG) is an increasingly utilized method for invasive monitoring in patients with medically intractable epilepsy. Yet, the lack of standardization for labeling electrodes hinders communication among clinicians. A rational clustering of contacts based on anatomy rather than arbitrary physical leads may help clinical neurophysiologists interpret seizure networks. We identified SEEG electrodes on post‐implant CTs and registered them to preoperative MRIs segmented according to an anatomical atlas. Individual contacts were automatically assigned to anatomical areas independent of lead. These contacts were then organized using a hierarchical anatomical schema for display and interpretation. Bipolar‐referenced signal cross‐correlations were used to compare the similarity of grouped signals within a conventional montage versus this anatomical montage. As a result, we developed a hierarchical organization for SEEG contacts using well‐accepted, free software that is based solely on their post‐implant anatomical location. When applied to three example SEEG cases for epilepsy, clusters of contacts that were anatomically related collapsed into standardized groups. Qualitatively, seizure events organized using this framework were better visually clustered compared to conventional schemes. Quantitatively, signals grouped by anatomical region were more similar to each other than electrode‐based groups as measured by Pearson correlation. Further, we uploaded visualizations of SEEG reconstructions into the electronic medical record, rendering them durably useful given the interpretable electrode labels. In conclusion, we demonstrate a standardized, anatomically grounded approach to the organization of SEEG neuroimaging and electrophysiology data that may enable improved communication among and across surgical epilepsy teams and promote a clearer view of individual seizure networks.

Gri Cevher Heterotopisi Bulunan Pediatrik Hastaların Manyetik Rezonans Görüntüleme Bulguları ve Eşlik Eden Malformasyonların Değerlendirilmesi

Objective: The aim of the present study is to classify gray matter heterotopias according to magnetic resonance imaging findings and to define the accompanying malformations. Methods: Images of all pediatric patients who were detected to have heterotopia in brain magnetic resonance imaging between January 2012 and June 2020 were retrospectively evaluated. The type, location of heterotopia, and accompanying cerebral anomalies were analyzed. Results: A total of 42 patients, 22 male, and 20 female, with a mean age of 7.80 ± 4.53 years (2-16 years) with gray matter heterotopia were included in the study. Of the patients, 33 (78.6%) had subependymal, 7 (16.7%) had subcortical, and 2 (4.7%) had band heterotopia. Twenty-four patients had epilepsy. Conclusion: The sub ependymal heterotopias were frequently located in the trigon region of the lateral ventricles. All subcortical heterotopias were in the frontal and unifocal locations. Band heterotopias were located bilaterally and subcortically in a symmetrical fashion in the cerebral hemisphere. The main accompanying anomalies were ventriculomegaly, Arnold-Chiari malformation, and corpus callosum agenesis. Considering the neurological developments of pediatric patients, it is important to identify the type of heterotopia and accompanying anomalies for patient management.

Incidental Findings in Head and Brain MRI of Military Pilots and Applicants: Consequences for Medical Flight Fitness

INTRODUCTION: With improved imaging technology, the number of incidental findings detected in cerebral MRI is increasing. This is a challenge that the German Air Force has to deal with in the context of standardized MRI examinations of young pilot candidates and pilots.METHODS: The German Air Force Centre of Aerospace Medicine hosted a 2-d conference to develop recommendations and procedures for the handling of some of the most frequently encountered cerebral incidental findings.RESULTS: Radiological MRI findings from a total of 2724 routine examinations of the skull of pilots and pilot applicants (26.8 ± 10.6 yr old; range from 16 to 62; over 80% range from 17 to 33; 96% men) revealed that in 28.1% of the examinations, one or more incidental findings were discovered. For seven of the following categories of incidental findings, decision guidelines could be established: white matter hyperintensities (N = 393; prevalence 14.4%; 95% CI 13.11-15.75), pinealis cysts (317; 11.6%; 10.43-12.84), developmental venous anomalies (64; 2.3%; 1.78-2.92), cavernomas (15; 0.6%; 0.27-0.83), aneurysms (14; 0.5%; 0.25-0.78), cholesterol granulomas (22; 0.8%; 0.47-1.14), and heterotopias of the gray matter (6; 0.2%; 0.04-0.4).CONCLUSION: Considering pilots health and aviation safety, a waiver decision is often possible after thorough discussion, depending on the specific criteria of the incidental finding and of the type of license.Kühn S, Sönksen S-E, Noble H-J, Knopf H, Frischmuth J, Waldeck S, Müller-Forell W, Weber F, Bressem L. Incidental findings in head and brain MRI of military pilots and applicants: consequences for medical flight fitness. Aerosp Med Hum Perform. 2022; 93(5):450-457.

Value of pre- and postnatal magnetic resonance imaging in the evaluation of congenital central nervous system anomalies

Fetal MRI and neonatal MRI of the central nervous system (CNS) are complementary tools that can help to accurately counsel and direct the management of children with anomalies of the central nervous system. Postnatal MRI can add to fetal MRI by allowing for monitoring of changes in the severity of disease, better delineation of a suspected prenatal anomaly, evaluation for secondary pathologies related to the primary diagnosis, and surgical management direction. In this review we discuss the roles of fetal and neonatal MRI in the diagnosis and treatment of congenital anomalies of the CNS through a series of case examples and how both are important in patient management.

A myriad spectrum of seizures on magnetic resonance imaging – A pictorial essay

Patients with seizures represent a challenging clinical population both in pediatrics and adults. Accurate diagnosis of the cause of a seizure is important in choosing an effective treatment modality, surgical planning, predicting a prognosis, and follow-up. Magnetic resonance (MR) imaging using a dedicated epilepsy protocol plays a key role in the workup of these patients. Additional MR techniques such as T2 relaxometry and MR spectroscopy show a promising role to arrive at a final diagnosis. The spectrum of epileptogenic causes is broad. Radiologists and physicians need to be updated and require a patterned approach in light of clinical history and electroencephalogram findings to arrive at a reasonable differential diagnosis. This pictorial essay aims to review a few of the common and uncommon causes of seizures and their imaging features.

Comparative Evaluation of Apparent Diffusion Coefficient Values of White Matter Surrounding the Heterotopia in Children With Unilateral Subependymal Heterotopia

Introduction: To compare the apparent diffusion coefficient (ADC) values of the white matter around heterotopia in children with unilateral subependymal heterotopia with those of the symmetrical normal cerebral hemisphere and control group.

Methods: Between January 2011 and September 2021, 15 pediatric patients with unilateral focal subependymal heterotopia among 47 patients with heterotopia detected in brain magnetic resonance imaging (MRI) in our hospital were included in the study. The control group consisted of 15 age- and sex-matched children with normal neurological examination and normal brain MRI. In brain MRIs, ADC value was measured from the white matter around the heterotopia area and from the opposite cerebral hemisphere matched to the location, and from the bilateral location-matched white matter of the control group. The area of heterotopia was measured on axial T1-weighted MRI. The data were evaluated statistically.

Results: There were eight girls and seven boys in the heterotopia group. The median age was 5.00 (min: 3, max: 14). There was no statistically significant difference between the ADC values of the heterotopia side and contralateral white matter of the heterotopia group. In addition, no statistically significant difference was found between the heterotopia side and opposite sides of the heterotopia and control groups ADC values.

Conclusion: According to the findings of this study, no difference was found in the ADC values of the white matter around the lesion in children with subependymal heterotopia compared to the opposite cerebral hemisphere and control groups.

MRI of Malformations of Cortical Development- A Comprehensive Review

MCDs (malformations of cortical development) are structural anomalies that disrupt the normal process of the cortical development. These include microcephaly with simplified gyral pattern/microlissencephaly, hemimegalencephaly, focal cortical dysplasia, lissencephaly, heterotopia, polymicrogyria and schizencephaly. They can present with intractable epilepsy, developmental delay, neurological deficits or cognitive impairment. Though the definitive diagnosis of MCD depends on histopathology, the pathological tissue is rarely available hence diagnosis begins with neuroimaging. This article shall briefly review the embryology followed by specific MRI imaging features of MCD in an attempt to simplify the process of diagnosing these disorders with clinical and genetic correlation.A table has been included to highlight the embryological, clinical and genetic findings associated with various MCDs.

Constitutional mismatch repair deficiency (CMMRD) presenting with high-grade glioma, multiple developmental venous anomalies and malformations of cortical development-a multidisciplinary/multicentre approach and neuroimaging clues to clinching the diagnosis

Constitutional mismatch repair deficiency syndrome (CMMRD) is a rare cancer-predisposition syndrome associated with a high risk of developing a spectrum of malignancies in childhood and adolescence, including brain tumours. In this report, we present the case of an 8-year-old boy with acute headache, vomiting and an episode of unconsciousness in whom brain imaging revealed a high-grade glioma (HGG). The possibility of an underlying diagnosis of CMMRD was suspected radiologically on the basis of additional neuroimaging findings, specifically the presence of multiple supratentorial and infratentorial developmental venous anomalies (DVAs) and malformations of cortical development (MCD), namely, heterotopic grey matter. The tumour was debulked and confirmed to be a HGG on histopathology. The suspected diagnosis of CMMRD was confirmed on immunohistochemistry and genetic testing which revealed mutations in PMS2 and MSH6. The combination of a HGG, multiple DVAs and MCD in a paediatric or young adult patient should prompt the neuroradiologist to suggest an underlying diagnosis of CMMRD. A diagnosis of CMMRD has an important treatment and surveillance implications not only for the child but also the family in terms of genetic counselling.

Magnetic resonance imaging findings and clinical characteristics in mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy in a predominantly adult cohort

OBJECTIVE

We aimed to better characterize the magnetic resonance imaging (MRI) findings of mild malformation of cortical development with oligodendroglial hyperplasia (MOGHE), a rare clinicopathological entity associated with pharmacoresistance recently described in patients with frontal lobe epilepsy.

METHODS

We studied 12 patients who underwent epilepsy surgery and whose surgical specimens showed histopathological findings of MOGHE, characterized by preserved cortical lamination, blurred gray-white matter interface due to increased number of oligodendrocytes, and heterotopic neurons in the white matter. The age at MRI evaluation ranged from 11 to 58 years, except for one 4.5-year-old patient.

RESULTS

Following a detailed MRI analysis using an in-house protocol, we found abnormalities in all cases. The lesion was circumscribed in the frontal lobe in six (50%) and in the temporal lobe in three (25%) patients. In the remaining three patients (25%), the lesion was multilobar (frontotemporal and temporoparieto-occipital). Cortical thickening was mild in all patients, except in the 4.5-year-old patient, who had pronounced cortical thickening and white matter blurring. We also identified cortical/subcortical hyperintense T2/fluid-attenuated inversion recovery signal associated with gray/white matter blurring in all but one patient. When present, cleft cortical dimple, and deep sulci aided in localizing the lesion. Overall, the MRI findings were like those in focal cortical dysplasia (FCD) Type IIa. Surgical outcome was excellent in five patients (Engel Class I in 25% and II in 17%). The remaining seven patients (58%) had worthwhile seizure reduction (Engle Class III). Incomplete lesion resection was significantly associated with worse outcomes.

SIGNIFICANCE

MRI findings associated with MOGHE are similar to those described in FCD Type IIa. Although more frequent in the frontal lobe, MOGHE also occurred in the temporal lobe or involved multiple lobes. Multilobar or extensive MOGHE MRI lesions are associated with less favorable surgical outcomes. Because this is a rare condition, multicenter studies are necessary to characterize MOGHE further.

Epileptic children with hemispheres' asymmetry. Quantitative brain magnetic resonance-based analysis of apparently unaffected hemisphere. Case-control study

OBJECTIVE

We performed a quantitative hemispheres analysis in epileptic children with hemispheres' asymmetry -due to unilateral dysplastic malformation- in order to recognize subtle volumetric changes of the contralateral and apparently unaffected hemisphere.

METHODS

13 children with Hemimegalencephaly (HME) and 20 with Hemimicrencephaly (Hme) were clustered in subgroups according to underlying hemispheric cortical dysplastic malformation and epilepsy pattern. 3D FSPGR T1weighted images were used to assess white and grey matter volumes for both hemispheres. Each volumetric parameter was compared with the average of an age-matched healthy control group.

RESULTS

HME subgroups: HME with pachygyria and focal (HME-PG-F; n 6) or multifocal epilepsy (HME-PG-MF; n.7). In both subgroups affected hemisphere (AH) volume was increased and contralateral hemisphere (CH) showed white matter volume reduction; in HME-PG-MF grey matter volume of CH was more reduced than HME-PG-F. Hme subgroups: Hme with polimicrogyria and focal epilepsy (Hme-PMG-F; n.8), Hme with giant subcortical nodular heterotopia and focal (Hme-SCH-F; n.6) or multifocal epilepsy (Hme-SCH-MF; n.6). In all subgroups AH volume was reduced; the volume of CH was significantly increased in Hme-PMG-F and Hme-SCH-MF while it was not significantly increased in Hme-SCH-F compared to affected hemisphere.

CONCLUSIONS

In patients with hemispheres' asymmetry, quantitative high-resolution MRI offers a more objective assessment of brain structures volume. The type of hemispheric dysplastic malformation together with the age of epilepsy onset and epileptic pattern may contribute to changes in contralateral and apparently unaffected hemisphere. Future studies are warranted to evaluate whether the early identification of these changes might help in planning future antiepileptic treatments.

Congenital Hearing Loss Is Associated With a High Incidence of Central Nervous System Abnormalities

OBJECTIVE(S)

To assess the incidence of central nervous system abnormalities in pediatric subjects with sensorineural hearing loss (SNHL).

METHODS

One hundred forty-three pediatric subjects evaluated for SNHL at a single academic center from 2007 to 2014 were included and divided into eight diagnosis groups based on etiology of SNHL. One hundred forty-three age- and gender-matched control subjects with no known brain-related pathology or history of hearing loss were included as healthy controls for comparison. Two neuroradiologists independently evaluated magnetic resonance imaging (MRI) and computed tomography (CT) scans for each subject. Comparison of abnormal cerebral development was performed using an ordinal logistic regression model. Concordance between CT and MRI of the temporal bone was assessed using the kappa statistic.

RESULTS

The etiologies of hearing loss in our cohort were 37.8% genetic, 12.6% infectious, 1.4% ototoxin-induced, and 48.3% idiopathic. Brain MRI revealed cerebral developmental abnormalities in defined regions in >30% of the SNHL cohort, significantly more than in normal-hearing pediatric controls. The Sylvian fissure, Virchow-Robin spaces, and lateral ventricles were most commonly affected. In the temporal bone, the percentage of subjects with concordant findings on CT and MRI was ≥92% across all anatomical structures.

CONCLUSION

MRI revealed a high incidence of intracranial abnormalities, suggestive of aberrant development of auditory and nonauditory neural structures associated with SNHL. CT and MRI share a high degree of concordance in detecting temporal bone anomalies. Inclusion of MRI as part of the workup of congenital SNHL may facilitate the detection of developmental anomalies of the brain associated with SNHL.

Superficial anatomy of the neonatal cerebrum - an ultrasonographic roadmap

Neurosonography is an essential imaging modality for assessing the neonatal brain, particularly as a screening tool to evaluate intracranial hemorrhage, hydrocephalus and periventricular leukomalacia. The primary advantages of neurosonography include portability, accessibility and lack of ionizing radiation. Its main limitations are intrinsic operator dependence and the need for an open fontanelle. Neurosonographic imaging acquisition is typically performed by placing a sector transducer over the anterior fontanelle and following sagittal and coronal sweeps. The sensitivity of neurosonography has markedly improved thanks to the adoption of modern imaging equipment, the use of dedicated head probes, and the employment of advanced diagnostic US techniques. These developments have facilitated more descriptive identification of specific cerebral anatomical details, improving understanding of the cerebral anatomy by conventional US. Such knowledge is fundamental for enhanced diagnostic sensitivity and is a key to understanding pathological states. Furthermore, familiarity with normal anatomy is crucial for understanding pathological states. Our primary goal in this review was to supplement these technological developments with a roadmap to the cerebral landscape. We accomplish this by presenting a systematic approach to using routine US for consistent identification of the most crucial cerebral landmarks, reviewing their relationship with adjacent structures, and briefly describing their primary function.

Neuroimaging manifestations and genetic heterogeneity of Walker-Warburg syndrome in Saudi patients

BACKGROUND

Walker-Warburg syndrome (WWS), an autosomal recessive disease, is the most severe phenotype of congenital muscular dystrophies. Its diagnosis remains primarily clinical and radiological. Identification of its causative variants will assist genetic counseling. We aim to describe genetic and neuroimaging findings of WWS and investigate the correlation between them.

METHODS

We retrospectively reviewed the clinical, genetic and neuroimaging findings of eleven Saudi neonates diagnosed with WWS between April 2012 and December 2018 in a single tertiary care center. Correlation between neuroimaging and genetic findings was investigated.

RESULTS

All patients had macrocephaly except one who had intrauterine growth restriction. Dysmorphic features were identified in nearly half of the patients. Creatine kinase levels were available in nine patients and were always elevated. Homozygous pathogenic variants were identified in all patients spanning POMT1 (n = 5), TMEM5 (n = 3), ISPD (n = 2) and POMT2 (n = 1) including one patient who had a dual molecular diagnosis of ISPD and PGAP2. On neuroimaging, all patients showed cobblestone cortex, classical infratentorial findings, and hydrocephalus. Other cerebral cortical malformations included subependymal heterotopia, polymicrogyria and open-lip schizencephaly in four, two and one patients, respectively. Buphthalmos and microphthalmia were the most prevalent orbital findings and found in all patients either unilaterally or bilaterally.

CONCLUSION

WWS is a genetically heterogeneous disorder among Saudis. The case with an additional PGAP2-related phenotype exemplifies the increased risk of dual autosomal recessive disorders in consanguineous populations. MRI is excellent in demonstrating spectrum of WWS brain and orbital malformations; however, no definite correlation could be found between the MRI findings and the genetic variant.

[Surgical treatment of epilepsy in children with focal cortical dysplasia]

OBJECTIVE

Surgery is the first-line treatment option in children with FCD and refractory epilepsy, but the rate of success and patient numbers who became free of seizures vary widely from series to series.

STUDY AIMS

To elicit variables affecting the outcome and predicting achievement of the long-term seizure-free status.

MATERIAL AND METHODS

One hundred sixty-nine children with cortical dysplasia and DR-epilepsy underwent surgery Preoperative evaluation included prolonged video-EEG and MRI (in all patients) and neuropsychological testing when possible. Fourteen patients underwent invasive EEG, fMRI and MEG were used also in some cases. Including 27 repeat procedures the list of overall 196 surgeries performed consists of: cortectomy (lesionectomy with or without adjacent epileptogenic cortices) – in 116 cases; lobectomy – in 46; and various disconnective procedures – in 34 patients. Almost routinely employed intraoperative ECOG (134 surgeries) was combined with stimulation and/or SSEP in 47 cases to map eloquent cortex (with CST-tracking in some). A new permanent and not anticipated neurological deficit developed post-surgery in 5 cases (2,5%). Patients were follow-upped using video-EEG and MRI and FU which lasts more than 2 years (median – 3 years) is known in 56 cases. Thirty-two children were free of seizures at the last check (57,2% rate of Engel IA). A list of variables regarding patients’ demography, seizure type, lesion pathology and localization, and those related to surgery and its extent were evaluated to figure out anyone associated with favorable outcome.

RESULTS

Both Type II FCDs and their anatomically complete excision are positive predictors for favorable outcome and achievement of SF-status (p<0,05). Residual epileptic activity on immediate post-resection ECOG do not affect the outcome.

CONCLUSION

Patients with Type II FCD, particularly with Type IIb malformations are the best candidates for curative surgery, including cases with lesions in brain eloquent areas. Kids with Type I FCD have much less chances to become free of seizures when attempting focal cortectomy. However, some of them with early onset catastrophic epilepsies may benefit from larger surgeries using lobectomy or various disconnections.

Agreement between prenatal ultrasound and 3.0T magnetic resonance imaging in the assessment of anomalies of the central nervous system: A single-center experience in Slovakia

OBJECTIVE

To assess the concordance of in-utero magnetic resonance imaging (MRI) findings at 3.0T in fetuses with suspect abnormalities of the central nervous system (CNS) on ultrasonography.

METHODS

A retrospective study was done on 222 pregnant women indicated for fetal MRI, with the examination performed within 2 weeks from indication. The inclusion criteria for patients were age 18 years or older with the fetus at 18 weeks of gestation or more. Fetal CNS pathologies were divided into six categories: ventriculomegaly; supratentorial midline abnormalities (ACC); supratentorial space-occupying lesions; abnormalities of the posterior fossa; destructive cerebral lesions; and cortical formation abnormalities (CFA). Chance-adjusted agreement was assessed using unweighted Cohen's kappa (κ).

RESULTS

The best agreement between ultrasound and MRI was observed in ventriculomegaly (κ=0.817; 95% confidence interval [CI] 0.76-0.88). There was only a moderate agreement in ACC (κ=0.483; 95% CI 0.35-0.61). CFA pathologies had a poor agreement between the modalities (κ=0.140; 95% CI -0.03 to 0.31).

CONCLUSION

Ultrasonography has good overall agreement with MRI in diagnosing fetal CNS anomalies. CFA had the most disagreement between ultrasound and MRI. The prognostic implication of these findings can be used for parental neuro-counseling but should be investigated further.

Abnormalities of the Fetal Central Nervous System: Prenatal US Diagnosis with Postnatal Correlation

Fetal central nervous system (CNS) abnormalities are second only to cardiac malformations in their frequency of occurrence. Early and accurate diagnosis at prenatal US is therefore essential, allowing improved prenatal counseling and facilitating appropriate referral. Thorough knowledge of normal intracranial anatomy and adoption of a logical sonographic approach can improve depiction of abnormal findings, leading to a more accurate differential diagnosis earlier in pregnancy. Four standard recommended views-transventricular, falx, cavum, and posterior fossa or transcerebellar views-provide an overview of fetal intracranial anatomy during the second trimester anatomy scan. Essential elements surveyed in the head and neck include the lateral cerebral ventricles, choroid plexus, midline falx, cavum septi pellucidi, cerebellum, cisterna magna, upper lip, and nuchal fold. CNS abnormalities can be organized into six main categories at prenatal US. Developmental anomalies include neural tube defects and neuronal migration disorders. Posterior fossa disorders include Dandy-Walker malformation variants and Chiari II malformation. Ventricular anomalies include aqueductal stenosis. Midline disorders include those on the spectrum of holoprosencephaly, agenesis of the corpus callosum, and septo-optic dysplasia. Vascular anomalies include vein of Galen malformations. Miscellaneous disorders include hydranencephaly, porencephaly, tumors, and intracranial hemorrhage. Correlation with postnatal MRI is helpful for confirmation and clarification of suspected diagnoses after birth. The authors discuss a standard US imaging approach to the fetal CNS and review cases in all categories of CNS malformations, providing postnatal MRI correlation when available.^©RSNA, 2020.

Prenatal diagnosis of central nervous system abnormalities: Neurosonography versus fetal magnetic resonance imaging

OBJECTIVE

To share our experience in diagnosis of congenital central nervous system (CNS) abnormalities by fetal magnetic resonance imaging (MRI).

STUDY DESIGN

This study consisted of 110 pregnancies. Neurosonography (NS) findings were compared with MRI results. Anomalies were categorized into 10 groups: 1) Corpus callosum (CC) and cavum septum pellucidum (CSP) anomalies, 2) Neural tube defects (NTD), 3) Posterior fossa anomalies (PFA), 4) Primary ventriculomegaly (PVM), 5) Microcephaly, 6) Macrocephaly, 7) Periventricular leukomalacia (PVL), 8) Craniosynostosis, 9) Intracranial hemorrhage (ICH) and 10) Lumbosacral teratoma. Demographic features, clinical characteristics and perinatal outcomes of the study subjects were evaluated.

RESULTS

Gestational weeks for NS and for MRI were 25.5 and 26.5 weeks, respectively. Fourteen (12.7%) pregnancies were terminated. PVM (n = 36, 32.7%), CC and CSP anomalies (n = 29, 26.3%), PFA (n = 11, 10%) and NTD (n = 11, 10%) were the most common fetal MRI indications. There were no statistically significant differences between the accuracy of fetal NS and fetal MRI for CC and CSP anomalies, NTDs, PFA and PVM (p = 0.09, 0.43, 0.45 and 0.23, respectively). However, fetal MRI was more accurate for the detection of normal anatomic findings in cases with suspected microcephaly, macrocephaly and craniosynostosis in NS when pooled together (p = 0.007). Furthermore, MRI also seemed to be advantageous in CC & CSP anomalies though it was not validated by statistical measures. No statistically significant difference was found for diagnostic performance of NS and MRI according to gestational week (p = 0.27).

CONCLUSION

Fetal MRI in addition to NS may improve diagnostic accuracy in pregnancies with congenital CNS abnormalities.

Prediction of Neurodevelopmental Impairment in Congenital Cytomegalovirus Infection by Early Postnatal Magnetic Resonance Imaging

INTRODUCTION

Congenital cytomegalovirus infection (CCMVI) may result in neurodevelopmental impairments (NDIs) such as hearing loss, developmental delay, epilepsy, and cerebral palsy. We aimed to investigate the potential for brain magnetic resonance imaging (MRI) to predict NDI in patients with CCMVI.

METHODS

We studied infants with CCMVI who were referred to our hospital from April 2010 to October 2018 and underwent a brain MRI within 3 months since birth. We screened for 6 classic presentations of CCMVI including ventriculomegaly, periventricular cysts, hippocampal dysplasia, cerebellar hypoplasia, migration disorders, and white matter abnormalities. Images were interpreted by a blinded pediatric radiologist. NDI was defined as having a developmental quotient <80, hearing dysfunction, blindness, or epilepsy requiring anti-epileptic drugs at approximately 18 months of corrected age.

RESULTS

The study involved 42 infants with CCMVI (median gestational age 38 weeks, birthweight 2,516 g). At least one abnormal finding was detected in 28 (67%) infants. Abnormal findings consisted of 3 cerebellar hypoplasia (7%), 7 migration disorders (17%), 26 white matter abnormalities (62%), 12 periventricular cysts (28%), 1 hippocampal dysplasia (2%), and 20 ventriculomegaly (48%). Abnormal findings were significantly more prevalent in infants with clinical symptoms (21/24, 91%) than in those without (7/19, 37%, p < 0.01). For NDI prediction, having ≥2 of ventriculomegaly, periventricular cysts, and white matter abnormality produced the highest Youden index values (0.78).

CONCLUSION

Infants with CCMVI with at least 2 of the abovementioned specific brain image abnormalities may be at high risk of developing NDI.

Pictorial Essay: Classic Signs in Pediatric Neuroradiology

BACKGROUND

A number of metaphorical imaging signs have been described in the radiology literature.

OBJECTIVE

These signs not only make the learning process easier but also increase diagnostic confidence. For this reason, these signs are quite popular among radiologists.

CONCLUSION

In this article, we have demonstrated classic signs described in pediatric neuroradiology with appropriate examples and illustrations.

A journey through formation and malformations of the neo-cortex

PURPOSE

Malformations of cortical development (MCD) are a heterogeneous group of disorders characterized by abnormal structure of the cerebral cortex. MCDs are an important cause of development delay and intractable epilepsy in children. In this review, we explore the embryological stages of development of neo-cortex, the imageology of various malformations which may occur during the journey of this development, the recent advances in imaging techniques used for diagnosing these malformations, and finally a simplified radiological approach to malformations of cortical development.

REVIEW

We discuss the classification of MCD according to the embryologic stage of cerebral cortex at which the abnormality occurred and the unique imaging features of various malformations, including microcephaly, hemimegalencephaly, lissencephaly, focal cortical dysplasia, heterotopias, polymicrogyria, schizencephaly, and neonatal CMV infection. Also, a rare variant of hemimegalencephaly, namely posterior quadrantic dysplasia, is illustrated; the diagnosis of which is crucial for neurosurgeons to decide management. The technological advancement in the imaging of MCD has taken a leap in the recent years. Imaging now also plays an enormous role in mapping of the abnormalities, delineation of proper surgical boundaries, and quantifying risks of visual, language, and sensorimotor dysfunction. With the introduction of various motor-sparing surgeries and disconnection procedures, proper identification and delineation of these malformations have gained utmost significance.

CONCLUSION

Knowledge of the wide imaging spectrum of MCD, familiarity with recent advances in imaging and an optimal radiological approach is essential for the general radiologist to accurately diagnose and prognosticate MCD as well as provide the best surgical approach to the operating surgeon.

Congenital pial AVF along the falx cerebri with complete agenesis of the corpus callosum and bilateral parasagittal pachygyria-polymicrogyria secondary to chronic ischemia

OBJECTIVE

Pial arteriovenous fistula (AVF) is an extremely rare entity due to direct arterial connection with the venous plexus without an intervening capillary network. The objective of this article is to describe a unique case of congenital pial AVF along the interhemispheric falx with complete callosal agenesis and malformation of cortical development within the bilateral anterior cerebral artery territories. We also demonstrated the distinctive feature of temporal stability of the extensive intracranial abnormalities without active intervention. Less than 100 cases have been reported thus far, most of which involve the adult rather than pediatric age group. A comprehensive literature review of congenital pial AVF will also be included.

CASE DESCRIPTION

A 5-year-old child presented with headache and complex partial seizures. Imaging of the brain revealed the presence of polymicrogyria-pachygyria in the parasagittal frontoparietal lobes with associated underlying white matter hypodensities. Complete agenesis of the corpus callosum was also seen. In addition, enlarged and tortuous vessels were noted along the interhemispheric falx with no appreciable nidus. Bilateral dilated and tortuous ACAs were seen supplying the network of abnormal vessels along the falx. The radiological findings were stable on a follow-up MRI 12 years later.

CONCLUSION

Our reported case adds to current limited knowledge of this rare entity in the pediatric age group, which is traditionally treated aggressively and urgently. Our case demonstrated temporal stability of this lesion with no detrimental complications observed. This suggests that the outcome of pial AVFs with conservative treatment may not be as grim as previously thought.

Dysplastic megalencephaly phenotype presenting with prenatal high-output cardiac failure

Dysplastic megalencephaly, also known as bilateral hemimegalencephaly, is a rare cerebral malformation characterized by bilateral cerebral hemisphere overgrowth and extensive malformation of cortical development. Affected patients present clinically with intractable seizures, severe neurological impairment and global developmental delay. There is a small body of literature reporting megalencephaly's association with neonatal high-output cardiac failure and a lack of literature describing prenatal findings. We report a case of dysplastic megalencephaly presenting with progressive high-output cardiac failure during fetal life. Prenatal and postnatal imaging findings as well as neonatal course are described. A companion case with similar imaging findings will help illustrate the prenatal imaging characteristics of this association. Knowledge of this potential complication related to dysplastic megalencephaly may help guide parental counseling and obstetric management.

MR imaging of neoplastic and non-neoplastic lesions of the brain and spine in neurofibromatosis type I

The aim of this work is to review the MR imaging of neoplastic and non-neoplastic lesions of the brain and spine in neurofibromatosis type I. Neoplastic lesions are optic pathway gliomas, brain stem gliomas, other gliomas of the brain, and peripheral nerve sheath tumors. Structural changes in the brain include unidentified bright objects, macrocephaly, and enlarged corpus callosum. Bony dysplasia changes as sphenoid ridge dysplasia, spinal scalloping, dural ectasia, and meningoceles. Vasculopathy and cortical cerebral and cerebellar malformations of the brain have been reported.

Imaging of Congenital Malformations

PURPOSE OF REVIEW

Intracranial congenital malformations are anomalies of brain development caused by genetic and environmental influences. This article discusses common intracranial congenital malformations, presents the associated neuroimaging findings, and discusses how appropriate identification of intracranial anomalies can impact diagnosis and treatment.

RECENT FINDINGS

Advances in neuroimaging techniques and genetic research have led to a better understanding of the pathogenesis of many congenital malformations, adding insight into their clinical relevance and the intricate relationship between critical periods of development, genetic predisposition, and environmental insults. When one malformation is discovered, a high likelihood of more malformations exists. In some instances, the intracranial anomalies will lead to the diagnosis of a particular neurologic syndrome, which may, in turn, lead to modification of a plan of care.

SUMMARY

Knowledge of congenital malformations and their appearance on imaging sequences is essential to improve clinical outcomes and quality of life for patients.

Using Correlative Properties of Neighboring Pixels to Improve Gray-White Differentiation in Pediatric Head CT Images

BACKGROUND AND PURPOSE

A lower radiation dose can have a detrimental effect on the quality of head CT images. The aim of this study performed in a pediatric population was to test whether an image-processing algorithm (Correlative Image Enhancement) based on the correlation among intensities of neighboring pixels can improve gray-white differentiation in head CTs.

MATERIALS AND METHODS

Sixty baseline head CT images with normal findings obtained from scans of 30 children were processed using Correlative Image Enhancement to produce corresponding enhanced images. Gray-white differentiation in baseline and enhanced images was assessed quantitatively by calculating the contrast-to-noise ratio and conspicuity in equivalent ROIs in gray and white matter. Two masked readers rated the images for visibility of gray-white differentiation on a 5-point Likert scale. Differences in both quantitative and qualitative measures of gray-white differentiation between baseline and enhanced images were tested for statistical significance. P values < .05 were considered significant.

RESULTS

Image processing resulted in improvement in the contrast-to-noise ratio (from 1.86 ± 0.94 to 2.26 ± 1.00, P = .02) as well as conspicuity (from 37.28 ± 11.56 to 46.4 ± 11.5, P < .001). This was accompanied by improved subjective visibility of gray-white differentiation as reported by both readers (P < .01).

CONCLUSIONS

Image processing using Correlative Image Enhancement had a beneficial effect on quantitative measures of gray-white differentiation. This translated into improved perception of gray-white differentiation by readers. Further studies are needed to assess the effect of such image processing on the detection of disease processes using head CTs.

Transcriptional and Post-Transcriptional Mechanisms of the Development of Neocortical Lamination

The neocortex is a laminated brain structure that is the seat of higher cognitive capacity and responses, long-term memory, sensory and emotional functions, and voluntary motor behavior. Proper lamination requires that progenitor cells give rise to a neuron, that the immature neuron can migrate away from its mother cell and past other cells, and finally that the immature neuron can take its place and adopt a mature identity characterized by connectivity and gene expression; thus lamination proceeds through three steps: genesis, migration, and maturation. Each neocortical layer contains pyramidal neurons that share specific morphological and molecular characteristics that stem from their prenatal birth date. Transcription factors are dynamic proteins because of the cohort of downstream factors that they regulate. RNA-binding proteins are no less dynamic, and play important roles in every step of mRNA processing. Indeed, recent screens have uncovered post-transcriptional mechanisms as being integral regulatory mechanisms to neocortical development. Here, we summarize major aspects of neocortical laminar development, emphasizing transcriptional and post-transcriptional mechanisms, with the aim of spurring increased understanding and study of its intricacies.

Infectious causes of microcephaly: epidemiology, pathogenesis, diagnosis, and management

Microcephaly is an important sign of neurological malformation and a predictor of future disability. The 2015-16 outbreak of Zika virus and congenital Zika infection brought the world's attention to links between Zika infection and microcephaly. However, Zika virus is only one of the infectious causes of microcephaly and, although the contexts in which they occur vary greatly, all are of concern. In this Review, we summarise important aspects of major congenital infections that can cause microcephaly, and describe the epidemiology, transmission, clinical features, pathogenesis, management, and long-term consequences of these infections. We include infections that cause substantial impairment: cytomegalovirus, herpes simplex virus, rubella virus, Toxoplasma gondii, and Zika virus. We highlight potential issues with classification of microcephaly and show how some infants affected by congenital infection might be missed or incorrectly diagnosed. Although Zika virus has brought the attention of the world to the problem of microcephaly, prevention of all infectious causes of microcephaly and appropriately managing its consequences remain important global public health priorities.

Prenatal and postnatal evaluation of polymicrogyria with band heterotopia

The coexistence of band heterotopia and polymicrogyria is extremely rare though it has been reported in the presence of corpus callosum anomalies and megalencephaly. We present prenatal and postnatal MRI findings of a rare case of diffuse cortical malformation characterized by polymicrogyria and band heterotopia. Agenesis of the corpus callosum and megalencephaly were also noted. In addition, bilateral closed-lip schizencephaly was identified on postnatal MRI, which has not been previously reported with this combination of imaging findings. Polymicrogyria with band heterotopia can occur and can be diagnosed with fetal MRI. The coexistence of corpus callosum anomalies and megalencephaly comprises a rare phenotype that has been previously described, suggesting an underlying genetic abnormality.

Voxel-based magnetic resonance image postprocessing in epilepsy

Objective

Although the general utility of voxel‐based processing of structural magnetic resonance imaging (MRI) data for detecting occult lesions in focal epilepsy is established, many differences exist among studies, and it is unclear which processing method is preferable. The aim of this study was to compare the ability of commonly used methods to detect epileptogenic lesions in magnetic resonance MRI‐positive and MRI‐negative patients, and to estimate their diagnostic yield.

Methods

We identified 144 presurgical focal epilepsy patients, 15 of whom had a histopathologically proven and MRI‐visible focal cortical dysplasia; 129 patients were MRI negative with a clinical hypothesis of seizure origin, 27 of whom had resections. We applied four types of voxel‐based morphometry (VBM), three based on T1 images (gray matter volume, gray matter concentration, junction map [JM]) and one based on normalized fluid‐attenuated inversion recovery (nFSI). Specificity was derived from analysis of 50 healthy controls.

Results

The four maps had different sensitivity and specificity profiles. All maps showed detection rates for focal cortical dysplasia patients (MRI positive and negative) of >30% at a strict threshold of p < 0.05 (family‐wise error) and >60% with a liberal threshold of p < 0.0001 (uncorrected), except for gray matter volume (14% and 27% detection rate). All maps except nFSI showed poor specificity, with high rates of false‐positive findings in controls. In the MRI‐negative patients, absolute detection rates were lower. A concordant nFSI finding had a significant positive odds ratio of 7.33 for a favorable postsurgical outcome in the MRI‐negative group. Spatial colocalization of JM and nFSI was rare, yet showed good specificity throughout the thresholds.

Significance

All VBM variants had specific diagnostic properties that need to be considered for an adequate interpretation of the results. Overall, structural postprocessing can be a useful tool in presurgical diagnostics, but the low specificity of some maps has to be taken into consideration.

Role of conventional magnetic resonance imaging in the screening of epilepsy with structural abnormalities: a pictorial essay

Epilepsy is a chronic neurological disease with serious impact on patients and society. The causes of epilepsy comprise a heterogeneous group of disorders, rendering epilepsy diagnoses rather difficult and challenging. The primary role of MRI is to locate and define the probable anatomic epileptogenic lesions. In the developing countries, where functional MRI (fMRI) is not popular, conventional MRI (cMRI) becomes especially important in epilepsy diagnoses. Apart from that, an experienced radiologist can increase the diagnostic yield of MRI to epileptogenic lesions. Thus, we present a pictorial review focusing on the role of cMRI in the screening of epilepsy with structural abnormalities and highlighting the key findings on cMRI to help radiologists to be familiar with the characteristic findings. Considering the complexity and diversity of the structural abnormalities, we propse a mnemonic "MAGIC TVs" approach to reduce false negative diagnosis and improve the diagnosis rate.