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We study the asymptotic behaviour of the solutions of the equation u=Au+λu−|u|u. Denoting by λ the principal eigenvalue of the second-order differential operator A, we shall prove that if λ ⩽ λ the only equilibrium solution, namely zero, is asymptotically stable, whereas, if λ>λ, the nontrivial equilibrium solutions without internal zeros are asymptotically stable. Attractivity and stability are proved both in the L-norm and in the H-norm. [ABSTRACT FROM AUTHOR]

An abstract of the article "Congenital cytomegalovirus infection: an interesting case of clinical, molecular and pathologic correlations," S. Visentin and colleagues is presented.

Sobolev inequalities in two-dimensional hyperbolic space are dealt with. Here is modeled on the upper Euclidean. half-plane equipped with the Poincaré–Bergman metric. Some borderline inequalities, where the leading exponent equals the dimension, are focused. The technique involves rearrangements of functions, and tools from calculus of variations and ordinary differential equations.

The role of intercalatus nucleus of Staderini (INS), the most caudal of the perihypoglossal nuclei, is much debated. Last research seems to suggest that this nucleus plays a role as a vertical eyes movements integrator. The few clinical reports present in the literature that describe isolated lesions of the INS have described patients presenting in acute with up-beating vertical spontaneous nystagmus. Isolated acute lesion of INS is, in fact, much rare, and, without other neurological signs, is exceptional. We present a case of acute isolated vertigo with no other neurological signs or symptoms, due to INS ischemia provoked by vertebral artery stenosis. The patient presented with spontaneous vertical up-beating nystagmus that showed at videonystagmographic recording, a clear exponential decay of angular slow-phase velocity, that is considered a typical sign of neural integrator impairment. This case seems to represent a further confirm that INS is part, as a vertical-to-position neural integrator, of the neural circuit controlling the vertical eyes movements., Competing Interests: The authors declare that they have no conflict of interest. This study has no grant or funding., (© 2023 PLA General Hospital Department of Otolaryngology Head and Neck Surgery. Production and hosting by Elsevier (Singapore) Pte Ltd.)

The clinical phenotype of Cyclin-Dependent Kinase-Like 5 (CDKL5) deficiency disorder (CDD) has been delineated but neuroimaging features have not been systematically analyzed. We studied brain magnetic resonance imaging (MRI) scans in a cohort of CDD patients and reviewed age at seizure onset, seizure semiology, head circumference. Thirty-five brain MRI from 22 unrelated patients were included. The median age at study entry was 13.4 years. In 14/22 patients (85.7%), MRI in the first year of life was unremarkable in all but two. In 11/22, we performed MRI after 24 months of age (range 2.5-23 years). In 8 out of 11 (72.7%), MRI showed supratentorial atrophy and in six cerebellar atrophy. Quantitative analysis detected volumetric reduction of the whole brain (-17.7%, P-value = 0.014), including both white matter (-25.7%, P-value = 0.005) and cortical gray matter (-9.1%, P-value = 0.098), with a reduction of surface area (-18.0%, P-value = 0.032), mainly involving the temporal regions, correlated with the head circumference (ρ = 0.79, P-value = 0.109). Both the qualitative structural assessment and the quantitative analysis detected brain volume reduction involving the gray and white matter. These neuroimaging findings may be related to either progressive changes due to CDD pathogenesis, or to the extreme severity of epilepsy, or both. Larger prospective studies are needed to clarify the bases for the structural changes we observed., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Carotid artery (CA) dissection is a rare etiology of neonatal arterial ischemic stroke (NAIS)., Methods: We describe one novel case and conduct a systematic literature review on NAIS attributed to CA dissection, to collect data on its clinical-radiological presentation, treatment, and outcome., Results: Eight published cases of NAIS attributed to CA dissection were identified and analyzed with our case. All patients (nine of nine) were born at term, and eight of nine experienced instrumental/traumatic delivery or urgent Caesarean section. None had fetal problems during pregnancy or thrombophilia. Signs and symptoms at presentation (between days of life 0 and 6) included seizures (eight of nine), respiratory distress or irregular breathing (five of nine), hyporeactivity, decreased consciousness or irritability (four of nine), and focal neurological signs (two of nine). At magnetic resonance imaging (MRI), stroke was unilateral in seven of nine and extensive in five of nine. CA dissection was documented by neuroimaging or at postmortem studies (seven of nine), and hypothesized by the treating physicians based on delivery and neuroradiology characteristics (in the remaining two of nine). Antithrombotic treatment was used in two of nine. According to available follow-up, one of eight died at age seven days, seven of eight had neurological/epileptic sequelae, and CA recanalization occurred in three of four., Conclusions: NAIS attributed to CA dissection is rarely identified in the literature, often preceded by traumatic/instrumental delivery, presenting with seizures and systemic signs/symptoms, and often characterized by extensive MRI lesions and neurological sequelae. Definite evidence and recommendations on antithrombotic treatment are lacking., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: There is limited research on brain lesions in children with cerebral visual impairment (CVI) of heterogeneous etiologies and according to associated subtyping and vision dysfunctions. This study was part of a larger project establishing data-driven subtypes of childhood CVI according to visual dysfunctions. Currently there is no consensus in relation to assessment, diagnosis and classification of CVI and more information about brain lesions may be of potential diagnostic value. Aim: This study aimed to investigate overall patterns of brain lesions and associations with level of visual dysfunction and to compare the patterns between the classification subgroups in children with CVI. Methods: School-aged children with CVI received ophthalmological and neuro-psychological/developmental assessments to establish CVI-related subtyping. Other pediatric information was collected from medical records. MRI scans were coded according to a semi-quantitative template including brain regions (right hemisphere, left hemisphere, visual pathways) and summed for total scores. Non-parametric analyses were conducted. Results: 28 children had clinical brain MRI scans available [44% of total sample, Group A (lower severity of visual dysfunctions) n = 16, Group B (higher severity) n = 12]. Total brain scores ranged between 0 and 18 (Group A mdn = 7, IQR = 0.8-10.0, Group B mdn = 10, IQR = 6.5-11.8) and were widespread across regions. 71 per cent had post-geniculate visual pathway damage. The median total brain and hemisphere scores of Group B were higher than subgroup A but differences did not reach statistical significance. No statistically significant associations were found between brain scores and vision variables (acuity, contrast sensitivity). Conclusion: This study found a spread of lesions across all regions on the brain scans in children with congenital CVI. The majority had damage in the postgeniculate visual pathways and visual cortex region suggesting this is an area of interest and potentially informative for diagnosis. However the subtyping classification did not show differences in number or region of lesions though the trend was higher toward Group B. This study confirms the complex diffuse and variable nature of brain lesions in children with congenital CVI, many of whom have other neurological impairments., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sakki, Dale, Mankad, Sargent, Talenti and Bowman.)

In the first days after birth, a major focus of research is to identify infants with hypoxic-ischemic encephalopathy at higher risk of death or severe neurological impairment, despite therapeutic hypothermia (TH). This is especially crucial to consider redirection of care, according to neonatal outcome severity. We aimed to seek associations between some neonatal routine parameters, usually recorded in Neonatal Intensive Care Units, and the development of severe outcomes. All consecutive patients prospectively recruited for TH for perinatal asphyxia, born between February 2009 and July 2016, were eligible for this study. Severe outcome was defined as death or major neurological sequelae at one year of age. Among all eligible neonates, the final analysis included 83 patients. Severe outcome was significantly associated with pH and base excess measured in the first hour of life, mode of delivery, Apgar score, Sarnat and Sarnat score, electroencephalogram-confirmed neonatal epileptic seizures, and antiepileptic therapy. Studying univariate analysis by raw relative risk (RR) and 95% confidence intervals (CI), severe outcome was significantly associated with pH ( p = 0.011), Apgar score ( p = 0.003), Sarnat score ( p < 0.001), and Caesarian section ( p = 0.015). Conclusions. In addition to clinical examination, we suggest a clinical-electroencephalographic protocol useful to identify neonates at high neurological risk, available before rewarming from TH.

Purpose: Rhabdomyosarcoma (RMS) is a malignant tumor frequent in children. The frequency and characteristics of cranial nerve involvement in pediatric head and neck (H&N) RMS have been scarcely reported. The aim of this study is to review a large cohort of pediatric head and neck RMS with an emphasis on cranial nerve involvement., Methods: We retrospectively reviewed H&N RMS cases from 3 tertiary hospitals over a 10-year period. Cranial nerve involvement was defined as radiologically apparent tumor extension along a nerve and/or the presence of secondary signs. Scans were reviewed by two pediatric neuroradiologists, blinded to clinical data., Results: A total of 52 patients met the inclusion criteria. Histologically, 39/52 were embryonal RMS, while 13/52 were alveolar RMS. Regional lymph nodes metastases were present in 19.2%. Cranial nerve involvement was present in 36.5%. Nerves were mainly involved as a direct extension of the mass through skull base foramina or after invasion of cavernous sinus, Meckel's cave, orbital apex, or stylomastoid foramen., Conclusion: Cranial nerve involvement is frequent in pediatric head and neck RMS and occurs secondary to "geographic" invasion due to direct extension through skull base foramina or cavernous sinus. These tumors never showed distant perineural metastatic disease as is seen in cases of adult head and neck carcinomas. This implies a different biological interaction between the nerves and these tumors in comparison to adult H&N tumors., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Monoallelic mutations on TMEM63A have been recently reported as cause of a previously unrecognized disorder named "infantile-onset transient hypomyelination". Clinical and neuroradiological presentation is described as highly similar to Pelizaeus-Merzbacher Disease but evolution over time was surprisingly benign with a progressive spontaneous improving course. We report on a new TMEM63A-mutated girl. The clinical picture was similar to the one already described except for the presence of recurrent episodes of unilateral eyelid twitching, and for the evidence of spinal cord involvement on MRI. These are interesting findings helping in distinguishing this condition from classic PMD since early disease stages. However, additional observations are needed to confirm if these are common features of this condition., (© 2021. The Author(s), under exclusive licence to The Japan Society of Human Genetics.)

The importance of fetal magnetic resonance imaging (MRI) in the prenatal diagnosis of central nervous system (CNS) anomalies is rapidly increasing. Fetal MRI represents a third level examination usually performed, as early as 18-20 weeks of gestational age, when a second level (expert) neuro-ultrasonography (US) evaluation raises the suspicion of a CNS anomaly or when a genetic disorder is known. Compared to the US, MRI has the advantage to allow a better visualization and characterization of brain structures so to detect anomalies not visible in the US, thus resulting in relevant implications for parent counselling and pregnancy management. Moreover, the improvement of MRI technologies permits to obtain ultrafast sequences, which minimize the drawback of movement artifacts, and to perform advanced studies. This review aims at providing a practical guide for trainees and fellows who are approaching fetal MRI. In the first part, we provide information about indications, safety and protocols based on the state-of-the-art sequences, with a mention on the innovations related to the use of a 3T scanner. The second part is focused on the normal development of the human fetal brain related to its MR appearance, whose knowledge is essential to detect possible abnormalities. The last section briefly describes the most frequent abnormalities in the fetal brain and spine as depicted by MRI., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/tp-20-293). The series “Pediatric Neuroradiology for Trainees and Fellows: An Updated Practical Guide” was commissioned by the editorial office without any funding or sponsorship. The authors have no other conflicts of interest to declare., (2021 Translational Pediatrics. All rights reserved.)

Background and Purpose: Walker-Warburg syndrome, muscle-eye-brain disease, and Fukuyama congenital muscular dystrophy are α-dystroglycan-related muscular disorders associated with brain malformations and eye abnormalities in which no structural inner ear abnormality has been described radiologically. We collected patients from 6 tertiary pediatric hospitals and reported the radiologic features and frequency of inner ear dysplasias., Materials and Methods: Patients previously diagnosed clinicoradiologically with Walker-Warburg syndrome, muscle-eye-brain disease, or Fukuyama congenital muscular dystrophy were included. We recorded the pathogenic variant, when available. Brain MR imaging and/or CT findings were reviewed in consensus, and inner ear anomalies were classified according to previous description in the literature. We then correlated the clinicoradiologic phenotype with the inner ear phenotype., Results: Thirteen patients fulfilled the criteria for the Walker-Warburg syndrome phenotype, 8 for muscle-eye-brain disease, and 3 for Fukuyama congenital muscular dystrophy. A dysplastic cochlea was demonstrated in 17/24. The most frequent finding was a pronounced cochlear hypoplasia type 4 with a very small anteriorly offset turn beyond the normal-appearing basal turn (12/13 patients with Walker-Warburg syndrome and 1/11 with muscle-eye-brain disease or Fukuyama congenital muscular dystophy). Two of 8 patients with muscle-eye-brain disease, 1/3 with Fukuyama congenital muscular dystrophy, and 1/13 with Walker-Warburg syndrome showed a less severe cochlear hypoplasia type 4. The remaining patients without Walker-Warburg syndrome were healthy. The vestibule and lateral semicircular canals of all patients were normal. Cranial nerve VIII was present in all patients with diagnostic MR imaging., Conclusions: Most patients with the severe α-dystroglycanopathy Walker-Warburg syndrome phenotype have a highly characteristic cochlear hypoplasia type 4. Patients with the milder variants, muscle-eye-brain disease and Fukuyama congenital muscular dystrophy, more frequently have a normal cochlea or milder forms of hypoplasia., (© 2021 by American Journal of Neuroradiology.)

Objective: To formulate a classification system for foetal cortical formation abnormalities (CFAs) based on in utero magnetic resonance (iuMR) appearances and trial it in 356 cases., Methods: This retrospective study included all cases of foetal CFA diagnosed between 2000 and 2017 from seven centres in Italy and UK. All of the studies were reviewed by a panel of paediatric neuroradiologists experienced in iuMR with the aid of an algorithm designed to categorise the abnormalities., Results: Consensus expert review confirmed 356 foetuses with CFA and the first level of classification distinguished bilateral CFA (229/356-64%) from unilateral CFA (127/356-36%) cases with sub-classification of the bilateral cases into asymmetric (65/356-18%) and symmetric (164/356-46%) involvement. There was a statistically significant excess of foetuses with small head size, e.g. 17% of the cohort had a bi-parietal diameter < 3rd centile. There was a small but statistically significant excess of males in the cohort. Further categorisation was made on fine anatomical structure., Conclusions: It is often not possible to classify foetal CFA using the principles and nomenclature used in paediatric neuroradiology. We have created a classification system for foetal CFA based on the analysis of 356 cases and believe that this will assist future research designed to correlate ante-natal and post-natal imaging features and understand the clinical sequelae of CFA described in utero., Key Points: • We describe a morphological classification system of foetal brain cortical formation abnormalities that can be used in clinical practice. • This classification system can be used in future research studies to evaluate the long-term imaging and clinical outcomes of foetal brain cortical formation abnormalities in 17- to 38-week gestational age range. • The practical value of the work is in providing a framework and language to look for imaging clues that may differentiate between different CFA in further studies.

To report feasibility, safety, and technical advantages of flat-detector computed tomography perfusion (FD-CTP) during balloon test occlusion (BTO) angiography studies, 10 patients patients scheduled for BTO were evaluated. Cerebral blood volume maps were extracted from FD-CTP images acquired during the test. The FD-CTP perfusion combined with BTO is feasible and safe in intracranial tumor, and aneurysm cases in which vessel sacrifice should be considered.

Objectives: We investigated whether prenatal magnetic resonance imaging (MRI) within 26 weeks of gestation (GW) may predict the fate of isolated upward rotation of the cerebellar vermis (URCV)., Methods: This retrospective multicentre observational study included foetuses diagnosed with isolated URCV in prenatal MRI performed within 26 GW. Isolated URCV was defined by a brainstem-vermis angle (BVA) ≥ 12° in the MR midline sagittal view without abnormalities of the supratentorial structures, brainstem, or cerebellum hemispheres. The assessments included the BVA, clival-supraoccipital angle, transverse diameter of the posterior cranial fossa, tentorial angle, width of the cisterna magna (WCM), ventricular width, vermian diameters, hypointense stripes, and cerebellar tail sign. Late prenatal or postnatal MRI was used as a reference standard to assess the final vermian fate (rotated/de-rotated)., Results: Forty-five foetuses (mean GW at prenatal MRI = 21.5 ± 1.4 weeks) were included. In the reference standard, the vermis was de-rotated in 26 cases (57.7%). At least two of the following criteria were used to predict the persistence of URCV at imaging follow-up: BVA ≥ 23°, WCM ≥ 9 mm, and the cerebellar tail sign. The results were a sensitivity of 84.21% (95% CI, 60.4-96.6%), specificity of 80.8% (95% CI, 60.6-93.4%), positive predictive value of 76% (95% CI, 58.7-87.8%), and negative predictive value of 87.5% (95% CI, 70.9-95.2%)., Conclusions: MRI within 26 GW on foetuses diagnosed with isolated URCV may predict delayed cerebellar vermis de-rotation, which is associated with good neurodevelopmental outcome in most cases., Key Points: • Foetal MRI is a valuable tool in predicting the fate of isolated upward-rotated cerebellar vermis. • A wider angle between the brainstem and vermis is associated with higher risk of persistence of vermian rotation. • The presence of ≥ 2 factors among a brainstem-to-vermis angle ≥ 23°, width of the cisterna magna ≥ 9 mm, and the presence of the "cerebellar tail sign" has a sensitivity of 84.21% (95% CI, 60.4-96.6%) and specificity of 80.8% (95% CI, 60.6-93.4%) in predicting the persistence of the vermian rotation at imaging follow-up.

Purpose: To describe in detail the temporal bone and brain findings in both common and rare syndromic causes of hearing loss, with the purpose of broadening among radiologists and enhance the current understanding of distinct imaging features in paediatric patients with syndromic hearing loss., Methods: A detailed search of electronic databases has been conducted, including PubMed, Ovid Medline, Scopus, Cochrane Library, Google Scholar, National Institute for Health and Care Excellence (NICE), Embase, and PsycINFO., Results: Syndromic causes of hearing loss are characterised by different and sometimes specific abnormalities in the temporal bone., Conclusion: A complete knowledge of the image findings in the temporal bones, brain, skull and other body regions is critical for the optimal assessment and management of these patients., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: Understanding the underlying pathophysiology and the patterns of disease spread is crucial in accurate image interpretation. In this pictorial review, the common and important inflammatory processes of the temporal bone in children will be discussed, and key computed tomography (CT) and magnetic resonance imaging (MRI) features described., Methods: Inflammatory processes are categorized by anatomical location: the petrous apex and the inner, middle and outer ear. A complete review of the literature is provided., Results: Cholesteatoma, cholesterol granuloma and mucoceles are inflammatory processes that occur across the anatomical subsites of the temporal bone, whilst site-specific inflammatory processes include labyrinthitis ossificans in the inner ear and keratosis obturans in the external ear. Infection is a key cause of inflammation in the temporal bone, and specific infections include petrous apicitis, otitis media and necrotizing otitis externa. Finally, important mimics and do-not-touch lesions are considered. CT and MRI are complementary in assessing these disorders, as two of the most important diagnostic clues are the presence of bone erosion, best appreciated on CT, and true diffusion restriction as seen on MRI. Flow charts to assist in the diagnosis of paediatric temporal bone inflammatory disease are also provided., Conclusion: Paediatric temporal bone inflammatory processes are common and can have severe clinical sequelae. Timely intervention, facilitated by correct radiological diagnosis, can often prevent progression of disease, loss of hearing and systemic illness.

Patients with X-linked deafness carry mutations in the POU3F4 gene and have pathognomonic inner ear malformations characterised by symmetrical incomplete partition type 3 (absent modiolus and lamina spiralis but preserved interscalar septum in a normal-sized cochlea) and large internal auditory meatus (IAM) with an increased risk of gusher during stapes surgery. We describe a range of fairly characteristic malformations in the hypothalamus of some patients with this rare condition, ranging from subtle asymmetric appearance and thickening of the tuber cinereum to more marked hypothalamic enlargement. We discuss the role of POU3F4 in the normal development of both the inner ear and hypothalamus and the proposed pathophysiology of incomplete partition type 3.