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117 result(s) for "Brunelle, F."
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A framework to study the cortical folding patterns
This paper describes a decade-long research program focused on the variability of the cortical folding patterns. The program has developed a framework of using artificial neuroanatomists that are trained to identify sulci from a database. The framework relies on a renormalization of the brain warping problem, which consists in matching the cortices at the scale of the folds. Another component of the program is the search for the alphabet of the folding patterns, namely, a list of indivisible elementary sulci. The search relies on the study of the cortical folding process using antenatal imaging and on backward simulations of morphogenesis aimed at revealing traces of the embryologic dimples in the mature cortical surface. The importance of sulcal-based morphometry is illustrated by a simple study of the correlates of handedness on asymmetry indices. The study shows for instance that the central sulcus is larger in the dominant hemisphere.
Neural basis of interindividual variability in social perception in typically developing children and adolescents using diffusion tensor imaging
Humans show great interindividual variability in the degree they engage in social relationship. The neural basis of this variability is still poorly understood, particularly in children. In this study, we aimed to investigate the neural basis of interindividual variability in the first step of social behavior, that is social perception, in typically developing children. For that purpose, we first used eye-tracking to objectively measure eye-gaze processing during passive visualization of social movie clips in 24 children and adolescents (10.5 ± 2.9 y). Secondly, we correlated eye-tracking data with measures of fractional anisotropy, an index of white matter microstructure, obtained using diffusion tensor imaging MRI. The results showed a large interindividual variability in the number of fixations to the eyes of characters during visualization of social scenes. In addition, whole-brain analysis showed a significant positive correlation between FA and number of fixations to the eyes,mainly in the temporal part of the superior longitudinal fasciculi bilaterally, adjacent to the posterior superior temporal cortex. Our results indicate the existence of a neural signature associated with the interindividual variability in social perception in children, contributing for better understanding the neural basis of typical and atypical development of a broader social expertise.
Superior temporal sulcus anatomical abnormalities in childhood autism: a voxel-based morphometry MRI study
The underlying neurobiology of autism, a severe pervasive developmental disorder, remains unknown. Few neocortical brain MRI abnormalities have been reported. Using rest functional brain imaging, two independent studies have described localized bilateral temporal hypoperfusion in children with primary autism. In order to search for convergent evidence of anatomical abnormalities in autistic children, we performed an anatomical MRI study using optimized whole-brain voxel-based morphometry (VBM). High-resolution 3-D T1-weighted MRI data sets were acquired in 21 children with primary autism (mean age 9.3 ± 2.2 years) and 12 healthy control children (mean age 10.8 ± 2.7 years). By comparing autistic children to normal children, we found bilaterally significant decreases of grey matter concentration located in superior temporal sulcus (STS) ( P < 0.05 corrected, after small volume correction; SVC). Children with autism were also found to have a decrease of white matter concentration located in the right temporal pole and in cerebellum ( P < 0.05, corrected) compared to normal children. These results suggest that autism is associated with bilateral anatomical abnormalities localized in the STS and are remarkably consistent with functional hypoperfusion previously reported in children with autism. The multimodal STS areas are involved in highest level of cortical integration of both sensory and limbic information. Moreover, the STS is now recognized as a key cortical area of the “social brain” and is implicated in social perceptual skills that are characteristically impaired in autism. Therefore, the convergent anatomical and functional temporal abnormalities observed in autism may be important in the understanding of brain behavior relationships in this severe developmental disorder.
A common pattern of brain MRI imaging in mitochondrial diseases with complex I deficiency
ObjectiveTo identify a consistent pattern of brain MRI imaging in primary complex I deficiency. Complex I deficiency, a major cause of respiratory chain dysfunction, accounts for various clinical presentations, including Leigh syndrome. Human complex I comprises seven core subunits encoded by mitochondrial DNA (mtDNA) and 38 core subunits encoded by nuclear DNA (nDNA). Moreover, its assembly requires six known and many unknown assembly factors. To date, no correlation between genotypes and brain MRI phenotypes has been found in complex I deficiencies.Design and subjectsThe brain MRIs of 30 patients carrying known mutation(s) in genes involved in complex I were retrospectively collected and compared with the brain MRIs of 11 patients carrying known mutations in genes involved in the pyruvate dehydrogenase (PDH) complex as well as 10 patients with MT-TL1 mutations.ResultsAll complex I deficient patients showed bilateral brainstem lesions (30/30) and 77% (23/30) showed anomalies of the putamen. Supratentorial stroke-like lesions were only observed in complex I deficient patients carrying mtDNA mutations (8/19) and necrotising leucoencephalopathy in patients with nDNA mutations (4/5). Conversely, the isolated stroke-like images observed in patients with MT-TL1 mutations, or the corpus callosum malformations observed in PDH deficient patients, were never observed in complex I deficient patients.ConclusionA common pattern of brain MRI imaging was identified with abnormal signal intensities in brainstem and subtentorial nuclei with lactate peak as a clue of complex I deficiency. Combining clinico-biochemical data with brain imaging may therefore help orient genetic studies in complex I deficiency.
Parieto-occipital grey matter abnormalities in children with Williams syndrome
Williams syndrome (WS) is a neurodevelopmental disorder resulting from a hemizygous deletion of chromosome 7q11.23. The phenotype of WS consists of typical dysmorphic features, supravalvular aortic stenosis, infantile hypercalcemia and growth retardation. While language and facial recognition seem to be relatively spared, visuospatial constructive disabilities are a hallmark of the neurobehavioral profile of WS. In order to search for actual structural abnormalities underlying this precisely defined neurodevelopmental disorder, we performed anatomical magnetic resonance imaging (MRI) in 9 WS children (11.6 ± 3.1 years; age range: 5.5–15 years) and 11 normal age-matched control children (11.8 ± 2.2 years; age range: 8–15 years) using voxel-based morphometry (VBM). VBM is a fully automated whole-brain technique that delivers a voxel-wise assessment of regional grey and white matter concentration. A significant decrease in grey matter concentration was detected in the left parieto-occipital region of WS children ( P < 0.05 corrected height threshold). The location of this abnormality in WS children coincides with the location of the structural abnormality previously described using the same method in 13 WS adults. These parieto-occipital abnormalities are consistent with the cognitive profile of WS which includes severe visuospatial construction and numerical cognition deficits. The demonstration of identical structural abnormalities in both adults and children argues for their early origin. Additionally, our study provides support for the use of advanced structural imaging techniques in children, in order to improve our understanding of neurobehavioral phenotypes associated with well-defined genetic disorders.
Primary aneurysmal bone cysts in children: percutaneous sclerotherapy with absolute alcohol and proposal of a vascular classification
Background Percutaneous sclerotherapy is an effective treatment for aneurysmal bone cysts (ABCs). Objective The purpose of this study was to demonstrate the safety and efficacy of sclerotherapy with absolute alcohol and to propose a vascular classification of ABCs based on a retrospective review. Materials and methods This was a review of children treated with absolute alcohol sclerotherapy for ABC at a single institution from January 1995 until November 2009. Treatment response was evaluated radiographically and clinically. Cyst fluid was classified as clear, partially bloody, or bloody. Presence of any venous drainage of the cyst was assessed by injection of contrast medium into the cyst cavity. Results Twenty-nine children with ages ranging from 2 to 16 years were included. Treatment response was good in 17 (59%), partial in 9 (31%), and poor in 3 (10%) children. Venous drainage was absent in six out of seven clear-fluid cysts, which we classified as lymphatic. Drainage was present in all seven bloody-fluid cysts, which we classified as venous. In seven partially bloody-fluid cysts, venous drainage was seen in three. Conclusion Sclerotherapy with absolute alcohol is a safe and effective treatment of ABC. We propose classifying ABC as lymphatic or venous and suggest considering ABC intraosseous slow-flow vascular malformations.
AB1120 Juvenile dermatomyositis: A MRI scoring system to assess acute inflammation and damage
Background Magnetic Resonance Imaging (MRI) is a very sensitive method to demonstrate muscle inflammation, but there is no standardized scoring system to assess both inflammation and damage in juvenile dermatomyositis Objectives To propose and to validate a MRI scoring system assessing acute inflammation and damages findings in Juvenile Dermatomyositis (JD). Methods Children with JD referred to our institution for proximal thighs MRI between 1998 and 2009 were retrospectively included. The MRIs were analysed twice by two musculoskeletal paediatric radiologists with a 6 weeks interval. Inflammatory activity was scored including muscle œdema (0=none, 1=mild and 2=severe), fascial, subcutaneous fat and skin œdema (qualitative scale). Damages were scored including calcinosis in muscles, fascias, subcutaneous fat and skin (qualitative scale), muscle and fat atrophy (qualitative scale) and muscle fatty infiltration (0=none, 1=mild and 2=severe). Results 20 children were included (median age, 7.1 years; range, 1-15; 6 boys and 14 girls). 45 MRI were analysed, which 10 were performed in the 2 months diagnosis. The most common MRI findings were muscle œdema (80%) regarding inflammatory activity, and muscle fatty infiltration (24%) regarding damages. Both intra- and inter-observers agreements were excellent regarding global score (Intraclass Correlation Coefficient [ICC], from 0.95 [CI 95%, 0.87-0.98] to 0.97 [0.94-0.99] and 0.88 [0.74-0.95], respectively). Inter-observer ICC were also excellent regarding inflammatory and damage subscores (0.84 [0.73-0.91] and 0.89 [0.66-0.97], respectively). Conclusions MRI is a reliable and reproductible tool for analysing inflammatory activity and damage during JD. Disclosure of Interest None Declared
Practical management of hyperinsulinism in infancy
Hyperinsulinism in infancy is one of the most difficult problems to manage in contemporary paediatric endocrinology. Although the diagnosis can usually be achieved without difficulty, it presents the paediatrician with formidable day to day management problems. Despite recent advances in understanding the pathophysiology of hyperinsulinism, the neurological outcome remains poor, and there is often a choice of unsatisfactory treatments, with life long sequelae for the child and his or her family. This paper presents a state of the art overview on management derived from a consensus workshop held by the European network for research into hyperinsulinism (ENRHI). The consensus is presented as an educational aid for paediatricians and children's nurses. It offers a practical guide to management based on the most up to date knowledge. It presents a proposed management cascade and focuses on the clinical recognition of the disease, the immediate steps that should be taken to stabilise the infant during diagnostic investigations, and the principles of definitive treatment.
MR imaging of fetal cerebral anomalies
Prenatal diagnosis of fetal brain anomalies relies mainly upon ultrasonography. However, even in the most experienced hands, the technique has limitations for some difficult diagnoses. MRI is an excellent imaging modality for the paediatric and adult brain. To assess the value of prenatal MRI when a cerebral anomaly was detected by US and where the prognosis depended on the identification of other anomalies undetectable by US, or where fetuses were at risk for a CNS lesion even when the US was normal. Four hundred prenatal MRI examinations were performed since 1988, and confirmed by postnatal follow-up or pathological examination. Two-thirds of the examinations were performed after 25 weeks of gestation, one-third between 21 and 26 weeks. Fetal immobilisation was obtained by maternal premedication with flunitrazepam, administered orally 1 h before the examination. The examinations were performed on 1.5 T scanners using one or two surface coils. Prenatal MRI allowed the diagnosis of serious unsuspected lesions such as neuronal migration disorders, ischaemic and haemorrhagic lesions and the abnormalities observed in tuberous sclerosis. It helped to characterise ventricular dilatation and anomalies of the corpus callosum and of the posterior fossa. MRI is a valuable complementary tool when prenatal US is incomplete, doubtful or limited. Prenatal MRI is particularly useful for the detection of ischaemic and haemorrhagic lesions, neuronal migration disorders and tuberous sclerosis lesions. Detection of these associated anomalies worsens the fetal prognosis, has medico-legal implications and modifies obstetric management. Normal prenatal MRI does not exclude an anomaly.
Measuring the Impact of INNOVATION ACTIVITIES IN GOVERNMENT
Appropriate metrics enable organizations to track progress, identify their most effective activities, and communicate results and value to both the creators and consumers of innovative solutions. [...]metrics can drive the direction of the organization. The Obama administration took multiple steps to foster innovation, including accelerating the establishment of Acquisition Innovation Labs in agencies to implement innovative approaches to acquisition (Rung, 2016).3 In 2017, the Department of Defense (DoD) created the position of Under Secretary of Defense for Research and Engineering during the restructuring of the Office of the Under Secretary of Defense for Acquisition, Technology, and Logistics (AT&L) to \"better pursue the goals of technological superiority, affordable systems, and well-managed business operations\" (DoD, 2017). [...]one study discussed the government's need to enhance on-investment for research and development investments and listed several potential metrics for tech transitions, including the number of intellectual property disclosures, copyright assertions, patents, and technologies licensed (Minor, 2019). According to one researcher, the measures ofimpact ofpublic sector innovation have focused on organizational functions and successful case studies rather than objectives, people, and structures (Glor, 2019).