European recommendations on practices in pediatric neuroradiology: consensus document from the European Society of Neuroradiology (ESNR), European Society of Paediatric Radiology (ESPR) and European Union of Medical Specialists Division of Neuroradiology (UEMS)

Pediatric neuroradiology is a subspecialty within radiology, with possible pathways to train within the discipline from neuroradiology or pediatric radiology. Formalized pediatric neuroradiology training programs are not available in most European countries. We aimed to construct a European consensus document providing recommendations for the safe practice of pediatric neuroradiology. We particularly emphasize imaging techniques that should be available, optimal site conditions and facilities, recommended team requirements and specific indications and protocol modifications for each imaging modality employed for pediatric neuroradiology studies. The present document serves as guidance to the optimal setup and organization for carrying out pediatric neuroradiology diagnostic and interventional procedures. Clinical activities should always be carried out in full agreement with national provisions and regulations. Continued education of all parties involved is a requisite for preserving pediatric neuroradiology practice at a high level

Fistules artério-veineuses durales intracrâniennes à drainage veineux cortical (à propos de 38 observations)

LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Apport de l'imagerie du tenseur de diffusion dans l'atrophie multisystématisée

La maladie de Parkinson et l atrophie multisystématisée ont ceci de particulier que le diagnostic de certitude ne peut être obtenu du vivant du patient. L un des enjeux actuels est d approcher au plus prêt le diagnostic clinique réel du patient, pré requis indispensable à l étude de l histoire naturelle de la maladie, à une analyse fiable des données épidémiologiques de la maladie, à la bonne pratique des études de recherche pharmaceutique, à l évaluation clinique des thérapeutiques innovantes. S il est relativement aisé de poser le diagnostic de maladie de Parkinson à un stade avancé, il est en revanche beaucoup plus délicat de l établir au stade initial de l affection. C est avec l AMS que le diagnostic différentiel initial est le plus difficile. Actuellement les séquences morphologiques d IRM représentent une aide incontestable, mais les anomalies observées sont souvent inconstantes et apparaissent à un stade tardif. La première partie du travail visait à étudier de manière simultanée et complémentaire la macro et la microstructure cérébrale dans les deux pathologies en utilisant de manière combinée les techniques de morphométrie voxel à voxel (VBM) et d imagerie du tenseur de diffusion appliqué à l ensemble du cerveau (VB-DTI). Cette étude confirme les données classiques d atrophie putaminale dans l AMS-P et d augmentation de la diffusivité putaminale ; nous avons de surcroît mis en évidence une diminution de densité de substance grise dans le circuit moteur (cortex moteur primaire CMP gauche versus MP et aire motrice supplémentaire versus témoins) et une diminution de la fraction d anisotropie dans le CMP gauche versus témoins. Il existait donc des anomalies macro et microstructurelles dans le circuit moteur des patients AMS-P en révélant la destruction tissulaire dans le circuit moteur - indépendamment de la perte de volume détecté par VBM et en accord avec les données anatomopathologiques et les caractéristiques cliniques motrices.La deuxième partie du travail consistait à étudier la connectivité cérébrale et les modifications des connexions cortico-putaminales à l aide de la tractographie probabiliste. Nous avons étudié les modifications volumiques et les modifications microstructurales putaminales et tenté de dégager des profils utiles au diagnostic différentiel. Des séquences T1 haute résolution volumique et en tenseur de diffusion ont été acquises. Le putamen était segmenté de manière manuelle, le cortex de manière automatique à l aide du logiciel free surfer. Nous avons calculé la probabilité de connectivité entre le putamen et les régions corticales ipsilatérales motrice, associative et limbique. Les volumes putaminaux, surfaces corticales, paramètres de diffusion (diffusivité moyenne et fraction d anisotropie) ont été étudiés et comparés entre les groupes. Nous avons mis en évidence pour la première fois une altération des projections putamino-corticales motrices dans l AMS-P en bonne concordance avec l atteinte du putamen moteur dorsolatéral et l atteinte corticale motrice et prémotrice dans la maladie. L analyse multivariée permettait de discriminer AMS-P d AMS-C (forme cérébelleuse de l AMS), de MP et de témoins avec une sensibilité de plus de 75%. La troisième et dernière partie consistait à étudier les profils cognitifs dans les deux pathologies et les corrélations anatomo-cognitives à l aide de la VBM et de la VB-DTI. La pertinence de l évaluation cognitive classiquement effectuée dans le diagnostic différentiel maladie de Parkinson et atrophie multisystématisée est quasi nulle. De plus, les principales corrélations imagerie-cognition sont en bonne concordance avec les données de la littérature. L implication du système moteur dans l AMS sur le versant moteur semble se confirmer sur le plan cognitif. A notre connaissance aucune étude de corrélation imagerie-cognition en imagerie de diffusion dans la maladie de Parkinson ou l atrophie multisystématisée n a été publiée.A definite diagnosis of Parkinson s disease (PD) and multiple system atrophy (MSA) can only be confirmed neuropathologically. The clinical differentiation of the parkinsonian variant of multiple system atrophy (MSA-P) from PD is challenging, especially during the early stages of the disease. Early differentiation of these diseases is particularly important because the disorders differ in terms of progression, prognosis, and treatment responses. The aim of the first part of the study was to evaluate in vivo changes in the brain s macro- and microstructure in MSA-P and in PD and to characterize the cerebral anatomical differences between the two conditions. We used a combination of voxel-based morphometry (VBM) and whole-brain, voxel-based diffusion tensor imaging analysis (VB-DTI). In MSA-P patients, VBM analysis revealed a lower density of grey matter (GM) in a motor related circuit (especially in the left primary motor cortex, PMC), relative to PD patients, and in the left supplementary motor area (SMA), relative to controls). Diffusion tensor imaging analysis revealed lower fractional anisotropy (FA) values in the left PMC and the right cerebellum in MSA-P patients, compared with controls. Using a volumetric diffusion technique, our study revealed selective tissue degeneration in motor circuits, regardless of the volume loss detected in VBM and in agreement with pathology reports and clinical motor characteristics. Our findings suggest that MSA-P is characterized by both macro- and microstructural changes in the sensorimotor circuit. The aim of the second part of the study was to evaluate brain connectivity especially cortico putaminal connectivity using probabilistic tractography. We assessed volumetric and microstructural changes that occur within each of these subregions and try to establish the potential value of these changes in differential diagnosis.DTI and T1-weighted images were obtained using 1.5 T MRI. Putamen was manually segmented. The cortex was segmented using Freesurfer software and cortical regions were classified in three functional systems: motor, associative and limbic. Then, we calculated the connection probability between putamen and ipsilateral cortical target. Volumes and DTI parameters (fractional anisotropy FA, mean diffusivity MD) of the resulting DTI-based parcellations of the putamen were compared between groups. Comparisons between groups were carried out using bivariate non parametrics tests. Putamen microstructural changes were present in the two variants of MSA according to anatomopathological knowledge. Loss of motor connectivity in MSA-P patients can be explained partially by important volume loss of putamen. Statistical multivariate model combining few clinical criteria and data obtained by MRI-based parcellation allows discriminating MSA-P from MSA-C from PD patients and controls in more than 75% of cases.The third part s aim was to study the cognitive profile of MSA patients compared to PD patients and to evaluate the cognitive clinical correlations with VBM and VB-DTI brain MRI data. The contribution of standard neuropsychological examination to the differential diagnosis of both syndromes remains still limited. Our study revealed the main involvement of motor cortex in cognitive functions. From our knowledge, there is no study of cognitive correlations and DTI parameters in PD or in MSA.LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF

MRI atlas of the human hypothalamus.

International audienceGaining new insights into the anatomy of the human hypothalamus is crucial for the development of new treatment strategies involving functional stereotactic neurosurgery. Here, using anatomical comparisons between histology and magnetic resonance images of the human hypothalamus in the coronal plane, we show that discrete gray and white hypothalamic structures are consistently identifiable by MRI. Macroscopic and microscopic images were used to precisely annotate the MRI sequences realized in the coronal plane in twenty healthy volunteers. MRI was performed on a 1.5 T scanner, using a protocol including T1-weighted 3D fast field echo, T1-weighted inversion-recovery, turbo spin echo and T2-weighted 2D fast field echo imaging. For each gray matter structure as well as for white matter bundles, the different MRI sequences were analyzed in comparison to each other. The anterior commissure and the fornix were often identifiable, while the mammillothalamic tract was more difficult to spot. Qualitative analyses showed that MRI could also highlight finer structures such as the paraventricular nucleus, the ventromedial nucleus of the hypothalamus and the infundibular (arcuate) nucleus, brain nuclei that play key roles in the regulation of food intake and energy homeostasis. The posterior hypothalamic area, a target for deep brain stimulation in the treatment of cluster headaches, was readily identified, as was the lateral hypothalamic area, which similar to the aforementioned hypothalamic nuclei, could be a putative target for deep brain stimulation in the treatment of obesity. Finally, each of the identified structures was mapped to Montreal Neurological Institute (MNI) space

A three-dimensional deep learning model for inter-site harmonization of structural MR images of the brain: Extensive validation with a multicenter dataset

In multicenter MRI studies, pooling the imaging data can introduce site-related variabilities and can therefore bias the subsequent analyses. To harmonize the intensity distributions of brain MR images in a multicenter dataset, unsupervised deep learning methods can be employed. Here, we developed a model based on cycle-consistent adversarial networks for the harmonization of T1-weighted brain MR images. In contrast to previous works, it was designed to process three-dimensional whole-brain images in a stable manner while optimizing computation resources. Using six different MRI datasets for healthy adults (n=1525 in total) with different acquisition parameters, we tested the model in (i) three pairwise harmonizations with site effects of various sizes, (ii) an overall harmonization of the six datasets with different age distributions, and (iii) a traveling-subject dataset. Our results for intensity distributions, brain volumes, image quality metrics and radiomic features indicated that the MRI characteristics at the various sites had been effectively homogenized. Next, brain age prediction experiments and the observed correlation between the gray-matter volume and age showed that thanks to an appropriate training strategy and despite biological differences between the dataset populations, the model reinforced biological patterns. Furthermore, radiologic analyses of the harmonized images attested to the conservation of the radiologic information in the original images. The robustness of the harmonization model (as judged with various datasets and metrics) demonstrates its potential for application in retrospective multicenter studies

Erratum to: Chédiak-Higashi syndrome: brain MRI and MR spectroscopy manifestations (Pediatric Radiology, 10.1007/s00247-014-3256-x)

SCOPUS: er.jinfo:eu-repo/semantics/publishe

Sex steroid hormones-related structural plasticity in the human hypothalamus.

International audienceWe investigated the effects of an artificial menstrual cycle on brain structure and activity in young women using metabolic magnetic resonance imaging (MRI). We show that the activation of the hypothalamo-pituitary-gonadal axis during the pill-free interval of low-dose combined oral contraceptive use is associated with transient microstructural and metabolic changes in the female hypothalamus but not in the thalamus, a brain structure unrelated to reproductive control, as assessed by water diffusion and proton magnetic resonance spectra measurements. Our results provide neuroanatomical insights into the mechanism by which sex steroid hormones mediate their central effects and raise the intriguing possibility that specific regions of the neuroendocrine brain use ovarian cycle-dependent plasticity to control reproduction in humans. These MRI-based physiological studies may pave the way for the development of new diagnostic and treatment strategies in the central loss of reproductive competence in human syndromes, such as hypothalamic amenorrhea

Chédiak-Higashi syndrome: brain MRI and MR spectroscopy manifestations

Chédiak-Higashi syndrome is a rare inherited metabolic disorder characterized by partial oculocutaneous albinism, immunodeficiency, and neurological dysfunction. We present the brain magnetic resonance imaging (MRI) and MR spectroscopy (MRS) findings obtained during the accelerated phase of the disorder in an 8-year-old. The brain MRI manifestations at recurrences 15 months and 24 months later are reported as well.SCOPUS: re.jinfo:eu-repo/semantics/publishe

GDC 360° for the endovascular treatment of intracranial aneurysms: a matched-pair study analysing angiographic outcomes with GDC 3D Coils in 38 patients

International audienceThe purpose of this study was to determine whether coil embolisation with a new complex-shaped Guglielmi Detachable Coil (GDC 360°; Boston Scientific Neurovascular, Fremont, CA, USA) has any effect on the stability of aneurysm occlusion