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After Total Knee Arthroplasty (TKA), a global post-operative rehabilitation programme is commonly performed. However, this current program is not always adapted to every patient and it could be improved by deeply reinforcing weaker thigh muscles. To do this, a muscle volume estimation coupled with force evaluation is required to therefore adapt the rehabilitation as a specific patient exercise plan. In this paper, we presented an MRI protocol allowing the acquisition of the whole thigh as well as a semi-automated pipeline to segment two main groups of thigh muscles, i.e., the quadriceps femoris and the hamstrings muscles. The pipeline is based on a few cross-sections manually labelled and a 3D-spline interpolation using directed graphs corresponding points. The seven muscles of ten thighs (70 muscles in total) were segmented and reconstructed in 3D. To assess this pipeline, three types of metrics (volumetric similarity, surface distance, and classical measures) were employed. Furthermore, the inter-muscle overlapping was calculated as an additional metric. The results showed mean DICE was 99.6% (±0.1), Hausdorff Distance was 4.9 mm (±1.8) and Absolute Volume Difference was 2.97 cm3 (±1.94) in comparison to the manual ground truth. The average overlap was 2.05% (±0.54).Clinical Relevance- The proposed segmentation method is fast, accurate and possible to integrate in the clinical workflow of TKA.

Itch is a sensation defined as the urge to scratch. The central mechanisms of itch are being increasingly studied. These studies are usually based on experimental itch induction methods, which can be classified into the following categories: histamine-induced, induction by other non-histamine chemicals (e.g. cowhage), physically induced (e.g. electrical) and mentally induced (e.g. audio-visual). Because pain has been more extensively studied, some extrapolations to itch can be proposed and verified by experiments. Recent studies suggest that the itch-processing network in the brain could be disrupted in certain diseases. This disruption could be related to the implication of new regions or the exclusion of already engaged brain regions from itch-processing network in the brain.

Background Despite the prevalence of psoriasis, the processing of itch in psoriasis and its impact on the central nervous system (CNS) remain unclear. Objective We studied the influence of psoriasis on the CNS using magnetic resonance imaging techniques (fMRI and DTI, respectively) to investigate whether mentally induced itch can modify the functional connectivity or the white matter microstructure of the brain. Methods Fourteen patients with chronic psoriasis and 15 healthy controls were recruited. Itch was mentally induced in subjects by videos showing others scratching themselves. Results The observation of functional connectivity during the viewing the video revealed an interconnected network of brain regions that are more strongly coupled in psoriasis patients than in healthy controls. This network links the cerebellum, the thalami, the anteroposterior cingulum, the inferior parietal lobules, the middle temporal poles and the parahippocampal, hippocampal, lingual and supramarginal gyri. We also found connections with the right precuneus and both left insula and superior temporal gyrus. The DTI analysis showed that chronic itch affects the microstructure of white matter, including the anterior thalamic radiations, the superior and inferior longitudinal fasciculi, the corticospinal tracts, the cingulum, the external capsules, the inferior frontal-occipital fasciculi and both minor and major forceps. Conclusion Our results indicate that there could exist a network which is more interconnected in psoriasis patients. Among two building blocks of this network, the subnetwork encoding the perception and control of itch sensation is more affected than the subnetwork representing mentalizing and empathy. With an approach consisting of measuring microstructural changes at a local level in the brain, we also contradict the findings obtained with global measures which stated that chronic psoriasis cannot alter the anatomy of the brain. This confirms that itchy pathophysiological conditions have similar effects on functional and structural connectivity as those observed in chronic pain.

Purpose New multiple sclerosis (MS) disease-modifying therapies (DMTs), which exert beneficial effects through prevention of relapse, limitation of disability progression, and improvement of patients’ quality of life, have recently emerged. Nonetheless, these DMTs are not without associated complications (severe adverse events like. progressive multifocal leukoencephalopathy). Patient follow-up requires regular clinical evaluations and close monitoring with magnetic resonance imaging (MRI). Detection of new T2 lesions and potential brain atrophy measurements contribute to the evaluation of treatment effectiveness. Current MRI protocols for MS recommend the acquisition of an annual gadolinium (Gd) enhanced MRI, resulting in administration of high volume of contrast agents over time and Gd accumulation in the brain. Methods A consensus report was established by neuroradiologists and neurologists from the French Observatory of MS, which aimed at reducing the number of Gd injections required during MS patient follow-up. Recommendations The French Observatory of MS recommends the use of macrocyclic Gd enhancement at time of diagnosis, when a new DMT is introduced, at 6-month re-baseline, and when previous scans are unavailable for comparison. Gd administration can be performed as an option in case of relapse or suspicion of intercurrent disease such as progressive multifocal leukoencephalopathy. Other follow-up MRIs do not require contrast enhancement, provided current and previous MRI acquisitions follow the same standardized protocol including 3D FLAIR sequences.

Background: Analyzing MR scans of low-grade glioma, with highly accurate segmentation will have an enormous potential in neurosurgery for diagnosis and therapy planning. Low-grade gliomas are mainly distinguished by their infiltrating character and irregular contours, which make the analysis, and therefore the segmentation task, more difficult. Moreover, MRI images show some constraints such as intensity variation and the presence of noise. Methods: To tackle these issues, a novel segmentation method built from the local properties of image is presented in this paper. Phase-based edge detection is estimated locally by the monogenic signal using quadrature filters. This way of detecting edges is, from a theoretical point of view, intensity invariant and responds well to the MR images. To strengthen the tumor detection process, a region-based term is designated locally in order to achieve a local maximum likelihood segmentation of the region of interest. A Gaussian probability distribution is considered to model local images intensities. Results: The proposed model is evaluated using a set of real subjects and synthetic images derived from the Brain Tumor Segmentation challenge –BraTS 2015. In addition, the obtained results are compared to the manual segmentation performed by two experts. Quantitative evaluations are performed using the proposed approach with regard to four related existing methods. Conclusion: The comparison of the proposed method, shows more accurate results than the four existing methods.

Resume L’expertise medicale est un avis technique elabore par un medecin expert pour repondre a une mission qui lui a ete assignee. Le medecin radiologue peut intervenir dans le cadre de la recherche de la responsabilite medicale ou il devra eclairer le magistrat sur l’existence d’une eventuelle faute d’imprudence, de negligence ou de manquement a une obligation de prudence ou de securite. Il peut egalement etre sollicite pour realiser et interpreter des examens d’imagerie a la demande de juridictions (scanner post-mortem, determination de l’âge osseux…). D’une autre part, servir la justice, ne doit pas etre contradictoire aux obligations deontologiques et ethiques du radiologue expert ; il doit etre conscient des implications medico-legales de ses constatations, leur repercussion sur le cours de l’affaire.

Resume Le suicide est la huitieme cause de mortalite en France et la premiere cause chez les 25–34 ans. La pendaison, l’intoxication medicamenteuse et l’usage d’une arme a feu sont les principaux modes suicidaires. Le scanner post-mortem est une aide a l’autopsie pour confirmer le suicide et eliminer une autre cause de deces. En cas de pendaison, les lesions de l’os hyoide et/ou du cartilage thyroidien sont retrouvees dans un peu plus d’un cas sur deux a l’autopsie. Les lesions des vertebres cervicales sont rares, survenant en cas de chute d’une hauteur importante. Les reconstructions 3D permettent de visualiser le sillon laisse par le lien sur le cou. Dans les suicides par arme a feu, le scanner permet de determiner l’orifice d’entree et l’eventuel orifice de sortie, de visualiser les lesions parenchymateuses le long du trajet du projectile, et de localiser le projectile en cas de traumatisme penetrant. Le trajet du projectile est plus difficile a determiner au niveau thoraco-abdominal. Le scanner montre egalement des anomalies evocatrices en cas de suicide par noyade ou par arme blanche, mais son apport est plus limite en cas d’intoxication. Les phenomenes de decomposition et la modification de la position du corps vont limiter l’analyse des lesions tomodensitometriques.

Resume Dans le cadre de la creation d’un nouveau groupe de travail au sein de la SFR (le Gravit : « Groupe de recherche en autopsie virtuelle et imagerie thanatologique ») en octobre 2014, un questionnaire a ete elabore et une enquete a ete menee afin de dresser un etat des lieux de l’imagerie thanatologique en France, devant l’essor de cette nouvelle pratique radiologique sur notre territoire. La place et le role relatifs de l’imagerie postmortem en coupes vis-a-vis de la medecine legale s’affinent avec le temps entre l’examen externe du corps et l’autopsie medicolegale. Les indications commencent a etre bien etablies aujourd’hui, l’interet et l’apport scientifique du scanner pre-autopsique ne font aujourd’hui plus aucun doute. Il persiste cependant une grande heterogeneite nationale sur differents plans. Les enjeux pratiques et les contraintes organisationnelles sont resolus au cas par cas en fonction de l’architecture hospitaliere locale. Le financement et la valorisation de ces actes sont egalement tres disparates : les tarifs d’examen dependent des conventions locales avec l’administration hospitaliere, le Tribunal de grande instance ou la Cour d’appel. Une collaboration entre les services de radiologie et de medecine legale est absolument indispensable, et l’implication des manipulateurs est tout aussi primordiale. Si la formation s’etoffe progressivement de maniere significative pour les radiologues et les manipulateurs aussi bien sur le plan national qu’international, les efforts doivent etre poursuivis afin d’harmoniser les pratiques, ameliorer et uniformiser l’accessibilite a l’imagerie thanatologique en France.

Resume La selection des footballeurs de haut niveau de moins de 17 ans (U-17) repose sur des criteres d’âge. Pour limiter les fraudes la Federation internationale de Football Association (FIFA) a recours a la determination de l’âge osseux via l’imagerie par resonance magnetique (IRM) du poignet gauche chez ces candidats. L’objectif de cette revue est de decrire la technique de realisation et la place actuelle de l’IRM du poignet et son interpretation dans l’estimation de l’âge des footballeurs de moins de 17 ans qui se base sur l’analyse de la physe radiale distale.

Suicide is the eighth cause of mortality in France and the leading cause in people aged between 25 and 34 years. The most common methods of suicide are hanging, self-poisoning with medicines and firearms. Postmortem computed tomography (CT) is a useful adjunct to autopsy to confirm suicide and exclude other causes of death. At autopsy, fractures of the hyoid bone or thyroid cartilage, or both, are found in more than 50% of suicidal hangings. Cervical vertebra fractures are rare and only seen in suicide victims jumping from a great height. Three-dimensional reconstructions from CT data are useful to visualize the ligature mark on the neck. In suicides by firearm, postmortem CT shows entry and exit wounds, parenchymal lesions along the bullet path, as well as projectiles in case of penetrating trauma. However, in the chest and abdomen it is more difficult to identify the path of the projectile. Postmortem CT also shows specific features of suicide by drowning or stabbing, but its use is limited in cases of self-poisoning. The use of postmortem CT is also limited by decomposition and change of body position. This article presents the imaging features seen on postmortem CT according to the method of suicide.

Objectives The aim of this work was to study physiological aortic arch three-dimensional displacement using non-rigid registration methods and magnetic resonance imaging (MRI). Materials and methods Ten healthy volunteers underwent thoracic MRI. Prospective cardiac gating was performed with a 3D turbo field echo sequence to obtain end-systolic and end-diastolic MR images. The rigid and elastic behavior between these two cardiac phases was detected and compared using either an affine or an elastic registration method. To assess reproducibility, a second MRI acquisition was performed 14 days later. Results Affine registration between the end-systolic and end-diastolic MR images showed significant global translations of the aortic arch and the supra-aortic vessels in the x, y, and z directions (2.02 ± 1.6, −0.71 ± 1.1, and −1.21 ± 1.4 mm, respectively). Corresponding elastic registration indicated significant local displacement with a vector magnitude of 5.1 ± 0.89 mm for the brachiocephalic artery (BCA), of 4.26 ± 0.83 mm for the left common carotid artery (LCCA), and of 4.8 ± 0.86 mm for the left subclavian artery (LSCA). There was a difference in displacement between the supra-aortic trunks of the order of 2 mm. Vector displacement was not statistically different between the repeated acquisitions. Conclusions The present results showed important deformations in the ostia of supra-aortic vessels during the cardiac cycle. It seems that aortic arch motions should be taken into account when designing and manufacturing fenestrated endografts. The elastic registration method provides more precise results, but is more complex and time-consuming than other methods.

Introduction Le prurit se definit comme une sensation desagreable qui provoque le besoin de se gratter, impliquant donc plusieurs regions du cerveau. Les mecanismes centraux commencent a etre definis. Ils peuvent etre potentiellement differents selon les differentes pathologies cutanees. Pour comparer la perception des demangeaisons chez des patients atteints de psoriasis et chez des volontaires sains, nous avons utilise deux methodes de neuroimagerie : l’imagerie par resonnance magnetique de diffusion (IRM de diffusion ou DTI) et l’IRM fonctionnelle (IRMf). Materiel et methodes Le prurit mentalement induit ou prurit contagieux, induit par la vue d’une autre personne en train de se gratter, met en jeu un reseau neuronal similaire a celui observe dans le prurit. Nous avons recrute 15 volontaires sains et 14 patients atteints de psoriasis. Les deux groupes ont regarde une video standardisee et validee montrant d’autres personnes se grattant, alors que l’IRM etait realisee. Resultats Nos resultats montrent qu’il existe un reseau de regions du cerveau qui sont plus activees chez les patients atteints de psoriasis par la perception de demangeaisons, et que la microstructure de la substance blanche de leur cerveau est aussi differente. Ce reseau comprend le cervelet, les cortex cingulaires anterieur et posterieur, le gyrus para-hippocampique, l’hippocampe, le lobule parietal inferieur, le gyrus temporal moyen, le lobule lingual, le gyrus supramarginal, le thalamus, le cortex insulaire gauche, le precuneus droit et le gyrus temporal superieur gauche. Notre analyse de la DTI montre que les patients avaient une anisotropie fractionnelle augmentee dans les radiations thalamiques anterieures, le fasciculus superior longitudinal, les tractus corticospinaux, le cingulum, les capsules externes, le fascicule fronto-occipital inferieur, le forceps mineur, le forceps majeur, le fasciculus inferieur longitudinal gauche, et la substance blanche a cote de l’aire motrice supplementaire. Discussion Il existe donc un reseau de regions du cerveau qui sont plus activees par le prurit chez les patients atteints de psoriasis par rapport aux volontaires sains. Cette augmentation des connectivites ou l’utilisation plus frequente du reseau cerebral pour le grattage chez les patients peut aussi modifier la microstructure de la substance blanche. Conclusion Notre etude confirme que les maladies chroniques qui s’accompagnent de prurit, peuvent augmenter les connectivites fonctionnelles et structurelles du cerveau. Nous remercions la Societe Francaise de Dermatologie pour son soutien.

Spatio-temporal evolution of joint space width (JSW) during motion is of great importance to help with making early treatment plans for degenerative joint diseases like osteoarthritis (OA). These diseases can affect people of all ages leading to an acceleration of joint degeneration and to limitations in the activities of daily living. However, only a few studies have attempted to quantify the JSW from moving joints. In this paper, we present a generic pipeline to accurately determine the changes of the JSW during the joint motion cycle. The key idea is to combine spatial information of static MRI with temporal information of low-resolution (LR) dynamic MRI sequences via an intensity-based registration framework, leading to a high-resolution (HR) temporal reconstruction of the joint. This allows the temporal JSW to be measured in the HR domain using an Eulerian approach for solving partial differential equations (PDEs) inside a deforming inter-bone area where the HR reconstructed bone segmentations are considered as temporal Dirichlet boundaries. The proposed approach has been applied and evaluated on in vivo MRI data of five healthy children to non-invasively quantify the spatio-temporal evolution of the JSW of the ankle (tibiotalar joint) during the entire dorsi-plantar flexion motion cycle. Promising results were obtained, showing that this pipeline can be useful to perform large-scale studies containing subjects with OA for different joints like ankle and knee.

Dynamic MRI has made it possible to non-invasively capture the moving human joints in vivo. Real-time Fast Field Echo (FFE) sequences have the potential to reduce the effect of motion artifacts by acquiring the image data within a few milliseconds. However, the short acquisition times affect the temporal resolution of the acquired sequences. In this paper, we propose a post-processing technique to reconstruct the missing frames of the sequence given the reduced amount of acquired data, which leads to recover the entire joint trajectory outside the MR scanner. To do this, we generalize the Log-Euclidean polyrigid registration framework to deal with dynamic three-dimensional articulated structures by adding the time as fourth dimension : we first estimate the rigid motion of each bone from the acquired data using linear intensity-based registration. Then, we fuse these local transformations to compute the non-linear joint deformations between successive images using a spatio-temporal log-euclidean polyrigid framework. The idea is to reconstruct the missing time frames by interpolating the realistic joint deformation fields in the domain of matrix logarithms assuming the motion to be consistent over a short period of time. The algorithm has been applied and validated using dynamic data from five children performing passive ankle dorsi-plantar flexion.

Summary Objectives To determine the correct age in legal procedures is paramount in obtaining the age of majority. This study was designed to prioritize a reliable postcranial age estimators capable of accurately assessing ages around 18 years. Methods In this retrospective study, we used a two-step procedure (Iscan–Loth and Suchey–Brooks methods) to estimate the age range. CT test sample included 102 pubic symphysis and sternal end of the 4th ribs from male individuals aged from 13.5 to 87 years (median: 20.3). Two-D and 3D-CT reconstructions were performed. Analysis of the correlation between our age range estimation and the chronological age was performed using the Pearson, Lin, and Kappa coefficients and Bland–Altman analysis. Results In our study, we reported 97% of subjects for whom the estimate of their age compared to legal age of 18 years was feasible through this method. The Kappa coefficient between our age estimation compared to the legal age was 0.905. Conclusions Estimation of the legal age through CT scan, of the pubic symphysis and the distal end of the 4th rib, seems reliable and well correlated with whether the individual has more or less 18 years old.

BACKGROUND Magnetic resonance imaging (MRI) is rarely used for the exploration of skin, even if studies have validated both feasibility of skin MRI and its interest for anatomical, physiological, and biochemical study of the skin. The purpose of this study is to explore moisturizing of the different skin layers using 3-T scan. METHODS An MRI of the heel's skin was performed using a 23 mm coil diameter on a 3T scan with a FFE (Fast Field Echo) 3D T1-weighted sequence and a TSE (Turbo Spin Echo) calculation T2-weighted sequence (pixels size of respectively 60 and 70 μm). This study was conducted on 35 healthy volunteers, who were scanned before applying moisturizer topic and 1 h after applying it. Region of interest in the stratum corneum, the epidermis and the dermis were generated on the T2 mapping. The thickness of each layer was measured. The T1 sequence allowed accurate cross-examination repositioning to ensure the comparability of the measurements. RESULTS Among the 35 cases, two were excluded from the analysis because of movement artifacts. Measurements before and after moisturizer topic application displayed a T2 increase of 48.94% (P < 0.0001) in the stratum corneum and of 5.45% (P < 0.0001) in the epidermis yet without significant difference in the dermis. There was no significant link between the thickness of the stratum corneum and the T2 increase. However, there was a strong correlation between the thickness of the stratum corneum and the thickness of the epidermis (P < 0.001; rho=0.72). CONCLUSION High-resolution MRI allows fine exploration of anatomical and physiological properties of the skin and can further be used to extend the studies of skin hydration.

Resume La fibrinolyse intraveineuse etait jusque recemment le traitement le plus efficace pour traiter l’accident vasculaire ischemique cerebral a la phase aigue. Le scanner encephalique en contraste spontane et l’IRM cerebrale avec sequence de diffusion et T2* sont les deux moyens d’imagerie privilegies pour selectionner les patients thrombolysables. Les etudes MR CLEAN, EXTEND-IA, ESCAPE, SWIFT PRIME, REVASCAT, THERAPY et THRACE montrent la superiorite d’un traitement endovasculaire couple a la thrombolyse versus thrombolyse seule en cas d’occlusion proximale de la circulation cerebrale anterieure. Les techniques classiques d’angio-imagerie sont suffisantes pour localiser le thrombus et evaluer l’etat des axes vasculaires cervicaux et intracrâniens. Des techniques complementaires permettant la mesure du volume de tissu necrose, celui de la zone de penombre et l’estimation de la vascularisation collaterale cerebrale jouent un role important pour affiner la selection des patients eligibles a la neuroradiologie interventionnelle. Nous developpons dans cet article chacune de ces techniques d’imagerie actuellement disponible et en precisons l’interet et les limites. Ce panel des differents moyens d’imagerie a disposition du neurologue, du radiologue et du neuroradiologue interventionnel doit permettre de s’adapter au mieux a chaque situation.

International audience; Cerebral palsy is the leading cause of motor disabilities affecting children. The ankle is the most common equine musculoske-letal strain in children with cerebral palsy. Despite multiple medical and surgical therapies, postoperative recurrence rate is still very high (48%). A major reason for therapy failure is the lack of knowledge of the ankle joint biomechanics. Dynamic MRI can be used to acquire high resolution static data and low resolution temporal images. However, spatial and temporal data should be combined to provide the most comprehensive point of view to study joint motion. In this paper, we first present an intensity-based registration method to accurately estimate the rigid motion of the ankle bones. Second, we investigate the use of the log-euclidean framework to reconstruct a four-dimensional (3D+time) high-resolution dynamic MRI sequence from a low-resolution dynamic sequence and one high resolution static MR image. The proposed approach has been applied and evaluated on in vivo MRI data acquired for a pilot study on child motor disability. Results demonstrate the robustness of the proposed pipeline and very promising high resolution visualization of the ankle joint.

International audience; Magnetic resonance imaging (MRI) and computed tomography (CT) scans were used to analyse, respectively, the soft tissues and the bones of the heads of four common dolphins and three harbour porpoises. This imaging study was completed by an examination of anatomical sections performed on two odontocete heads (a subadult common dolphin and a subadult harbour porpoise). The three complementary approaches allowed to illustrate anatomical differences in the echolocation systems of the common dolphin and the harbour porpoise. We captured images confirming strong differences of symmetry of the melon and of its connexions to the MLDB (Monkeys Lips/Dorsal Bursae) between the common dolphin and the harbour porpoise. The melon of the common dolphin is asymmetrically directly connected to the right bursae cantantes at its right side, whereas the melon of the harbour porpoise is symmetrical, and separated from the two bursae cantantes by a set of connective tissues. Another striking difference comes from the bursae cantantes themselves, less deeply located in the head of the common dolphin than in the harbour porpoise.

Introduction For thirty years now, linear or macrocyclic gadolinium-based contrast agents (GBCAs) have been routinely used in MRI. They were initially assumed to have virtually no side effects, but gadolinium can accumulate in tissue, bone and brain. Moreover, linear GBCAs can cause nephrogenic systemic fibrosis, a debilitating and potentially life-threatening disease, for patients with kidney failure. Thus, the use of some linear GBCAs has been reduced over the last decade, and has even been stopped in Europe. Objectives Assess the evolution of the consumption of GBCAs in France and particularly in Finistere during the period 2011–2017. Provide explanation for this evolution. Material and methods We used the French Health Insurance Agency (CPAM) and the Brest university hospital databases to assess the evolution of GBCAs consumption and MRI examinations performed during the period 2011–2017. Results During this period 2011–2017, the number of GBCAs reimbursed boxes increased of 95 % in Finistere and of 119 % in France. There was a rise of 64 % in the consumption of GBCAs in the university hospital of Brest. The number of MRI examinations also increased during this period. The increase was of 65 % in private clinics in the Finistere. During this period, there was the equivalent of 1.5 MRI that were newly implemented in Finistere. Another point to consider was the increase of examinations realized by teleradiology. Conclusion Increase of GBCAs consumption during the period 2011–2017 in France ( Fig. 1 ) and particularly in Finistere is only partially related to the increase of MRI examinations’ number. Further studies should be performed to assess whether this increase of enhanced MRI examinations improves the patients’ management. As GBCAs are not recovered during wastewater treatment, impact of gadolinium concentrations increase in coastal seawaters should also be raised [1] , [2] .

Objectif Evaluer l’incidence des micro-saignements en IRM a 3 T, pendant le suivi, dans le territoire vasculaire d’une artere intracrânienne stentee lors du traitement d’un anevrisme intracrânien. Materiels et methode Etude retrospective par analyse visuelle qualitative de la presence ou non, et de la quantification de microsaignements dans le territoire de l’artere stentee sur des IRM avec sequences T2* et de susceptibilite magnetique realisees a 3 T a 3, 9, 12 et 24 mois post-operatoire dans le cadre du suivi systematique des patients comparativement a un groupe de patients traites par coils seuls. Les patients traites par stent ont tous recu une double anti-aggregation plaquettaire par Aspirine et Ticagrelor pendant 6 mois minimum apres la pose de stent, et sont sous Aspririne au long cours. Il a ete realise une double lecture par deux radiologues, un junior et un senior. Resultats 97 patients ont ete inclus de 2016 a 2018, et il a ete retrouve des microsaignements dans 27 cas (57,4 %) dans le groupe traite par coils et dans 39 cas (78 %) dans le groupe des patients stentes. La grande majorite des lesions nouvellement apparues se trouvaient dans le territoire arteriel de l’artere stentee. Dans tous les cas ou les patients possedaient une IRM pre-operatoire, ces microsaignements n’etaient pas presents initialement. Lors du suivi il existait dans environ 10 % des cas une majoration de la charge lesionnelle. Une excellente reproductibilite inter-observateur etait retrouvee. Conclusion Cette etude permet de mettre en evidence et faire discuter l’incidence des microsaignements cerebraux apres la pose d’un stent intracrânien chez ces patients sous antiplaquettaires au long cours.

We report a case of inflammatory cerebral amyloid angiopathy (CAA) that led to rapid cognitive decline, seizures, visual hallucinations, hyperproteinorrachia and right hemispheric leukopathy. Brain biopsy gave the diagnosis of CAA. Although no inflammatory infiltrate was found in the biopsy sample, corticosteroids led to a regression of the radiological lesions without significant clinical improvement. CAA is a rare disease, defined by lesions of classical cerebral amyloid angiopathy and perivascular infiltrates in contact with the affected vessels. In cases of rapidly progressive dementia associated with leukopathy, inflammatory amyloid angiopathy should be considered as cognitive disorders may improve after immunosuppressive therapy.

International audience; Magnetic resonance imaging (MRI) was used to scan the head of a common dolphin (Delphinus delphis) in order to visualize the different adipose tissues involved in echolocation functioning and to precisely delineate their anatomical topology. MRI scans were performed on the head taken from a freshly stranded carcass and repeated after a 2‐week freezing time followed by thawing. The main fatty organs of the head, that is the melon, the mandibula bulba, the bursae cantantes, and their different connections with surrounding tissues were identified and labelled. The nasal sacs, other organs of echolocation, were also identified and labelled thanks to different MRI acquisitions. The shape, the location, the type of MRI signal of each organ and of their different connections were successfully analysed on all images, and then, the images of the head fresh or after thawing were compared. No impacts of the freezing/thawing cycle on the fatty tissues of the head were identified. Different parts were distinguished in the melon on the basis of the MRI signal emitted, corresponding most likely to the internal and external melon already identified by other analytical approaches, and linked to differences in lipid composition. MRI is shown here to be a useful tool to study the functional anatomy of the organs responsible for echolocation in odontocetes, with a particularly high level of precision.

PurposeThe purpose of our study is to determine whether there is a relation between overweight, age, sex, “hospitalised/outpatient” status and a non-inflammatory hypersignal of the subcutaneous lumbosacral adipose tissue in T2 Short-Tau Inversion-Recovery (T2-STIR) MR imaging sequences.Patients and methodsOne hundred and six lumbar MRI, including a T2-STIR and T1 Fluid Attenuated Inversion-Recovery (FLAIR) weighted sagittal sequences, were retrospectively taken from the picture archiving and communication system (PACS) of our hospital and then made anonymous and analysed. The presence or absence of a T2-STIR hypersignal within subcutaneous adipose tissue behind the paraspinal muscle aponeurosis was determined. In addition, the weight, thickness of the fat tissue, the administrative status of the patient, the age, sex, time of the examination and, when present, the height of this hypersignal were noted. A uni- and multivariate analysis by logistic regression was carried out in order to examine the relationship between the data gathered.ResultsIn the examinations selected, 25.5% (n=27) demonstrated a T2-STIR hypersignal in the subcutaneous tissue. We identified the weight (P

Resume Objectifs Le but de notre etude est d’evaluer s’il existe une association entre le surpoids, l’âge, le sexe, le statut « hospitalise/externe » et un hypersignal non inflammatoire du tissu adipeux sous-cutane lombosacre en IRM sur la sequence T2 short-tau inversion-recovery (T2-STIR). Patients et methodes Cent-six IRM lombaires, comprenant une sequence sagittale ponderee T2-STIR et une ponderee T1 FLAIR, ont ete extraites retrospectivement, a partir du systeme d’archivage de notre l’hopital, puis anonymisees et analysees. La presence ou non d’un hypersignal T2-STIR au sein des tissus adipeux sous-cutanes en arriere de l’aponevrose des muscles paraspinaux a ete recherchee. De meme, le poids, l’epaisseur adipeuse, le statut administratif du patient, l’âge, le sexe, l’heure de realisation de l’examen et, lorsqu’il etait present, la hauteur de cet hypersignal ont ete enregistres. Une analyse uni- et multivariee par regression logistique a ete effectuee afin d’examiner les relations entre ces donnees. Resultats Sur les examens selectionnes, 25,5 % ( n = 27) ont montre un hypersignal T2-STIR dans l’hypoderme. Nous avons identifie le poids ( p p p p Conclusion Nous avons trouve une association significative entre le surpoids, l’âge et le statut « hospitalise » et une infiltration non inflammatoire du tissu adipeux lombaire. Ce phenomene semble correspondre a un œdeme interstitiel, lie a une stase sous-cutanee. Cette anomalie ne doit pas etre confondue avec une inflammation locale.

International audience

International audience; Segmentation of gliomas in magnetic resonance imaging (MRI) images is a crucial task for early tumor diagnosis and surgical planning. Although many methods for brain tumor segmentation exist, the improvement of this process is still difficult. Indeed, MRI images show complex characteristics and the different tumor tissues are difficult to distinguish from the normal brain tissues; especially the low-grade glioma (LGG), distinguished by their infiltrating character. In fact, it is difficult to extract the tumor from the surrounding healthy parenchyma tissue without any risk of neurological functional sequelae. The purpose of this paper is to provide an overview about a new MRI brain tumor segmentation method based on the local phase information. We applied the proposed method on a set of selected images (Flair, T1 and T1c). Those images were from patients with low-grade glioma. The preliminary results obtained seem to be interesting.

Resume Introduction Les nodules rhumatoides sont l’une des expressions extra-articulaires possibles de la polyarthrite rhumatoide. Peu frequents, ils sont tres majoritairement sous-cutanes, rarement visceraux, exceptionnellement meninges. Observation Nous rapportons l’observation d’un homme de 52 ans, atteint d’une polyarthrite rhumatoide resistante, chez qui des lesions meningees nodulaires furent mises en evidence sur une IRM cerebrale realisee dans les suites d’une baisse brutale d’acuite visuelle. Les premieres IRM de controle realisees ensuite detecterent l’apparition de nouvelles lesions asymptomatiques et la disparition des premieres. Une derniere IRM cerebrale realisee quatre ans apres le debut de la symptomatologie oculaire montra la disparition de toutes les lesions nodulaires extra-axiales. Ce caractere labile fit suspecter le diagnostic rare de nodules rhumatoides meninges. Conclusion Durant la periode de notre observation, notre patient recevait un traitement par methotrexate a faible dose, dose trop faible pour franchir la barriere hematoencephalique. Les lesions meningees ont ainsi pu evoluer selon l’histoire naturelle de la maladie. En depit d’une imagerie initiale non specifique, l’evolution radiologique du patient dans ce contexte plaidait en faveur du diagnostic final de nodules rhumatoides meninges.

Nella fase preospedaliera, la corsa contro il tempo inizia per evitare qualsiasi ritardo pregiudizievole per i pazienti. Il grande pubblico deve essere sensibilizzato ai sintomi precoci degli accidenti vascolari cerebrali (AVC) e deve essere istruito in modo da chiamare il prima possibile il 118: deficit motorio o sensitivo di un arto o di un emisoma, disturbo della visione, del linguaggio e dell’equilibrio e cefalee insolite. Il ruolo del Servizio di aiuto medico d’urgenza (SAMU) e quello di guadagnare tempo per la realizzazione della diagnostica per immagini che, da sola, permette di confermare la diagnosi e il meccanismo dell’AVC. La gestione preospedaliera permette di escludere un’intossicazione da ossido di carbonio e un’ipoglicemia. Questo trasferimento coordinato deve permettere un accesso immediato a un’unita neurovascolare (UNV), alla base di una riduzione del 20% della mortalita e della disabilita. La gestione ospedaliera permette di porre le indicazioni e le controindicazioni della fibrinolisi dopo un accesso prioritario a una diagnostica per immagini cerebrale che deve essere disponibile 24 ore su 24. Se si tratta di un infarto cerebrale da meno di 4 h 30, il neurologo di guardia deve eseguire una fibrinolisi con l’attivatore del plasminogeno tissutale ricombinante (rt-PA). Al di fuori della fibrinolisi endovenosa, che e l’unico trattamento curativo validato, i fattori aggravanti dovranno essere combattuti all’origine delle dieci misure di monitoraggio che permettono di identificare le complicanze e di trattarle. Oltre al bilancio laboratoristico comune e alla ricerca di una sindrome infiammatoria, di un’ipokaliemia fonte di aritmia cardiaca, di un’insufficienza cardiaca, di una trombofilia, di un’ipercolesterolemia e di un’ipertrigliceridemia, e opportuno prestare attenzione ai risultati del Doppler cervicale e intracranico per ricercare una dissecazione visibile precocemente ma molto fugace o una stenosi ateromatosa all’origine della carotide interna, i cui trattamenti in fase acuta e in prevenzione secondaria sono validati. L’ecografia transesofagea permette di escludere un forame ovale pervio con un aneurisma del setto interatriale, causa recentemente riconosciuta di infarti cerebrali cardioembolici in pazienti di meno di 55 anni, ma anche di piu di 55 anni.

Resume Introduction Le foramen sternal est une anomalie morphologique du developpement sternal qui a lieu lors de l’embryogenese. Cas clinique Les restes d’un cadavre humain ont ete decouverts a cote d’un vehicule sans permis, accidente, le proprietaire du vehicule etait signale comme disparu par ses proches depuis plusieurs mois. L’inspection minutieuse du corps du sternum revele un orifice bien centre dans son tiers superieur, transfixiant ; son unicite sa situation (communement reconnue comme « en regard du cœur ») et ses dimensions pouvaient correspondre au passage d’un projectile de 9 mm (calibre largement repandu). C’est une analyse tomodensitometrique post-mortem qui permettra rapidement d’eviter que l’enquete doive s’orienter vers une origine balistique du deces, en permettant d’affirmer le caractere non recent de la lesion, d’une part, et, d’autre part, d’evoquer d’emblee un foramen sternal sur les criteres suivant : presence de contours reguliers, sans marche d’escalier, sans trait fracturaire ni d’osteolyse focale, os corticalise, situation sur la ligne mediane, morphologie : « en goutte d’eau », comblement du foramen par du tissu d’attenuation graisseuse. Conclusion Le foramen sternal est une particularite anatomique qui n’est pas rare et qui doit etre connue aussi bien de la part des legistes que des radiologues. La non-description de cette variante anatomique dans les examens d’imageries anterieurs du patient temoigne que cette variante est plus accessible a l’imagerie en coupe comme le scanner.

High resolution MR imaging is ideal for pelvic imaging. To achieve good image quality at 3.0 Tesla MR, one may not simply import protocols used at 1.5 Tesla MR. Issues specific to 3.0 Tesla MR imaging must be considered including chemical shift, magnetic susceptibility, dielectric effect, specific absorption rates (SAR), motion artifacts and optimal echo time (TE) and repetition tome (TR) to achieve the desired tissue contrast. High quality pelvic MRI (prostate, rectum, and female pelvis) at 3.0 Tesla is possible. In addition, it offers potential advantages due to its ability to provide excellent vascular imaging and advances with functional imaging (diffusion, spectroscopy). This article discusses the parameters required to achieve quality pelvic imaging at 3.0 Tesla, the specifics of high-field MR imaging, and illustrates achievable clinical results.

Background: Atrial fibrillation (AF) is strongly associated with age, and epidemiologic studies are needed to evaluate the impact of both aging of the population and the use of anticoagulant therapy in patients with AF on the incidence of cardioembolic stroke with AF (CE/AF stroke). Methods: We evaluated trends in incidence rates, risk factors, prestroke therapy, and survival in CE/AF stroke from a prospective population-based registry, from 1985 to 2006. Results: A total of 3,064 ischemic strokes, including 572 (18.7%) CE/AF strokes, were recorded. Over the 22 years, a decrease in the incidence of overall CE/AF stroke was noted (incidence rate ratio 0.9858, 95% confidence interval [CI] 0.9731–0.9986; p = 0.03). We observed a higher prevalence of previous AF, previous myocardial infarction, and patients aged >70 years in CE/AF stroke ( p p = 0.003). A significant increase in the use of anticoagulants and antiplatelet agents was noted, and was particularly pronounced for CE/AF stroke with previous AF. For CE/AF stroke, survival rates were 72% at 1 month (95% CI 0.68–0.76), 52% at 1 year (95% CI 0.48–0.56), and 43% at 2 years (95% CI 0.39–0.48), and remained lower than those of other ischemic stroke. Conclusions: The decrease in the incidence of cardioembolic/atrial fibrillation stroke in our study was probably due to a slight increase in the utilization of antithrombotic therapy in patients with atrial fibrillation, but the use of such therapies will have to increase further because of the expected aging of the population in coming years. AF = atrial fibrillation; CE = cardioembolic; CI = confidence interval; IRR = incidence rate ratios.

There is little reliable population based information about the distribution of risk factors among the various ischaemic stroke subtypes, even though determining risk factor profiles is of major importance to develop targeted preventive strategies.The distribution of first ever ischaemic stroke subtypes was established in a prospective population based study conducted in Dijon, France (152,606 inhabitants). Cases were collected between January 2005 and December 2006, and were classified using TOAST classification. Vascular risk factors were recorded to determine a risk factor profile for each subtype.332 patients with first ever ischaemic stroke (150 men and 182 women) were recorded. Adjusted incidence to world population was 54/100,000/year. The distribution of ischaemic stroke subtypes was as follows: 119 (35.8%) cases of large artery atherosclerosis, 89 (26.8%) small artery occlusions, 81 (24.4%) cardioembolisms and 43 (13%) other and undetermined causes. The most frequent vascular risk factor was hypertension, irrespective of the ischaemic stroke subtype, with a total prevalence of 62%. Using multivariate regression, a positive association between cardioembolism and age (OR 1.051; 95% CI 1.026 to 1.076; p0.001) was demonstrated and between small artery occlusion and either high blood pressure (OR 1.86; 95% CI 1.06 to 3.27; p = 0.03) or hypercholesterolaemia (OR 2.23; 95% CI 1.33 to 3.76; p = 0.02).This comprehensive prospective population based study has demonstrated that vascular risk factors exhibit a particular distribution according to the ischaemic stroke subtypes. These findings, as well as the great frequency of hypertension among stroke patients, have implications for prevention strategies, the design of clinical trials and the organisation of health care services.

Introduction The central nervous system involvement has been reported in 20% of cases of primary Sjogren's syndrome (SS), a chronic autoimmune disease characterized by a disorder of the exocrine glands secondary to progressive lymphocyte infiltration. Classically described neurological manifestations include sensorimotor deficits, aseptic meningitis or meningoencephalitis, multiple sclerosis-like syndromes and myeolopathies. Observation We report here the case of a 53-year-old woman who exhibited rapidly progressive visual loss, disclosing bilateral optic neuropathy, as an uncommon initial symptom of primary SS. Examination of CSF revealed associated aseptic meningitis. Because of the lack of efficacy of the first treatment by intravenous corticosteroids, monthly intravenous cyclophosphamide was quickly introduced. After six months, significant visual recovery was observed. Conclusion Optic neuropathies have been rarely reported as the initial symptom revealing primary Sjogren syndrome, and bilateral simultaneous lesions remain exceptional.

Resume Introduction Le syndrome du canal tarsien est une neuropathie compressive du nerf tibial dont les etiologies sont multiples. Ce syndrome souvent meconnu est parfois difficile a diagnostiquer, car la symptomatologie est subjective. Observation Nous rapportons le cas d’un syndrome du canal tarsien post-traumatique ou l’IRM a permis d’evoquer le diagnostic en mettant en evidence les anomalies de signal des muscles innerves par le nerf tibial en lien avec leur denervation. Conclusion L’IRM est un complement efficace de l’electromyogramme (EMG) dans le diagnostic positif et etiologique du syndrome du canal tarsien.

Liver steatosis may evolve into steatohepatitis then cirrhosis with related complications. It may also contribute to hepatocellular failure, sometimes fatal after major hepatectomy, especially in the setting of liver transplantation with living donor. Imaging must allow non-invasive detection and accurate quantification. In and out of phase MR imaging routinely performed in clinical practice is a simple and robust means of achieving these goals. In this article, we will review the histological, pathophysiologic, and clinical features of liver steatosis and the key points of in and out of phase pulse sequences and underlying physical principles. The T2* relaxation, cause of a loss of signal between both echo times must be taken into account. Echo times must be known for image interpretation, and optimized, especially at 3T. Finally, the T1 of lipids and water is different and causes T1 effects that may lead to quantification errors while being advantageous for image interpretation. The combination of these factors allows detection and quantification of liver steatosis in routine clinical practice.

Resume Objectif Les tonsillolithes nasopharynges sont moins bien connus des radiologues que les lithiases des amygdales palatines. La possibilite de disposer en routine de coupes fines lors des scanners de la tete et du cou nous a pousse a realiser une etude retrospective sur l’etiogenie et sur la semiologie radiologique des tonsillolithiases nasopharyngees. Materiel et methodes 515 scanners ont ete retrospectivement relus a la recherche de calcifications de la paroi posterieure du nasopharynx. Un patient porteur d’une telle calcification a beneficie d’une IRM cerebrale dans le cadre du bilan etiologique de son malaise. Cet examen a permis dans le meme temps une etude de la paroi nasopharyngee. La taille, la densite et la position de ces concretions calciques ont ete analysees dans tous les cas au scanner. Resultats Nous avons decouvert chez 31 patients (18 hommes, 13 femmes) une ou plusieurs calcifications de l’espace muqueux pharynge. La taille de ces calcifications etait comprise entre 2 et 5,5 mm avec une densite mediane de 202 UH. Dans deux cas, nous avons observe que ces calcifications etaient rattachees a un kyste intra-adenoide, alors que dans trois cas les patients etaient porteurs de calcifications des tonsilles palatines et nasopharyngees. Aucun des 31 patients n’avait subi dans le passe une adenoidectomie. Les images de scanner ou d’IRM dans le plan sagittal ont permis de situer clairement toutes les calcifications en avant du fascia pharyngobasilaire. Discussion La position de ces calcifications nasopharyngees en avant du fascia pharyngobasilaire permet d’exclure un reliquat calcifie de la notochorde. De plus, la presence concomitante de calcifications tonsillaires nasopharyngees et palatines chez trois patients est un argument supplementaire pour considerer ces calcifications de la paroi posterieure du nasopharynx comme des tonsillolithes. Ces derniers, qui representent 6 % des scanners de notre serie, sont tous asymptomatiques. Conclusion Les tonsillolithes nasopharynges sont des calculs de taille infra-centimetrique loges dans les tonsilles pharyngees et frequemment detectes au scanner en l’absence de toute symptomatologie clinique.

RADIOLOGIE ET IMAGERIE MEDICALE : Musculosquelettique - Neurologique - Maxillofaciale - 31-646-A-10

We report a case of inflammatory cerebral amyloid angiopathy (CAA) that led to rapid cognitive decline, seizures, visual hallucinations, hyperproteinorrachia and right hemispheric leukopathy. Brain biopsy gave the diagnosis of CAA. Although no inflammatory infiltrate was found in the biopsy sample, corticosteroids led to a regression of the radiological lesions without significant clinical improvement. CAA is a rare disease, defined by lesions of classical cerebral amyloid angiopathy and perivascular infiltrates in contact with the affected vessels. In cases of rapidly progressive dementia associated with leukopathy, inflammatory amyloid angiopathy should be considered as cognitive disorders may improve after immunosuppressive therapy.

Resume L’IRM cerebrale est l’examen d’imagerie de reference, en pathologie infectieuse de l’encephale. L’arrivee de nouvelles IRM a gradient eleve, autorise de nos jours, le recours systematique a l’imagerie de diffusion qui permet de differencier un abces d’une tumeur cerebrale necrotique. La spectroscopie cerebrale du proton affine plus encore le diagnostic d’abces, en mettant a jour le metabolisme intime des germes a l’origine de l’abces. Cet article recommande l’utilisation d’un protocole d’exploration simple en IRM, capable d’affirmer la nature infectieuse du processus pathologique.

Examination of acute stroke by CT angiography is an alternative to MRI. Technological improvement of multidetector CT scanners allows neuroimaging of stroke in a multimodal protocol including plain CT, cerebral CT perfusion and CT angiography of the cervical and intracranial arteries. CT angiography is a reliable non invasive technique for the evaluation both extracranial and intracranial vessels that may be used as an alternative to MR angiography.

Resume Objectifs Analyse dosimetrique en angiographie cerebrale, en fonction du type de pathologie rencontree et de la technique utilisee. Materiels et methodes Exploitation des donnees cliniques et dosimetriques (produit dose × surface, nombre de serie, temps de scopie et de graphie), issues de 84 angiographies cerebrales diagnostiques et de 32 embolisations cerebrales. Resultats Les angiographies diagnostiques ont ete reparties en trois categories. A/ celle ou le diagnostic etait un anevrysme embolise secondairement : n = 17. B/ celle ou le diagnostic final etait celui d’une malformation arterio-veineuse (MAV) : n = 10. C/ celle qui ne comportait ni MAV, ni anevrysme a emboliser : n = 57. Les embolisations cerebrales ont ete classees en deux sous-groupes. K/ celui dans lequel l’embolisation a immediatement suivi l’angiographie diagnostique : n = 15. L/ celui ou l’embolisation de l’anevrysme n’a eu lieu que 24 a 48 H apres l’angiographie : n = 17. Le produit dose x surface (PDS) moyen du groupe B contenant les MAV est superieur aux valeurs des groupes A et C, du fait d’un allongement de la duree de la graphie. L’adjonction de series de reperage dans le groupe L contribue a l’augmentation du temps de pose (difference de temps significative : p = 0,0054), et donc, au fait que le PDS L est superieur au PDS K. Enfin, il existe une forte correlation entre la duree de la scopie et le PDS (n = 116 ; r = 0,931 ; p Conclusion Les angiographies cerebrales diagnostiques sont plus irradiantes en presence de MAV. Les PDS des embolisations sont plus eleves en cas de separation dans le temps des deux phases (diagnostique/therapeutique).

The main goal of urgent imaging evaluation of patients with suspected CNS infection is to differentiate infectious from tumoral or vascular lesions in order to provide appropriate management. MR imaging, including diffusion weighted imaging and spectroscopy, is superior to CT imaging to characterize lesion location and etiology. The CT and MRI features of the more frequent bacterial, viral and parasitic CNS infections will be described.

Les mouvements en miroir (MM + ) sont frequemment rapportes chez les patients ayant un syndrome de Kallmann (SK + ), en cas de mutation d’ANOS1 (KAL1) sur le chromosome X. Il n’a jamais ete decrit de MM + chez les femmes ANOS1 + . L’hypothese d’un defaut d’inhibition du faisceau pyramidal controlateral a ete proposee pour expliquer ces MM mais n’a jamais ete demontree. Objectif Tester l’hypothese d’un defaut de decussation et de developpement des voies pyramidales chez des patients SK + MM + . Methodes Analyse genetique dans une famille comprenant 11 hommes SK + MM + et 2 femmes SK-MM + (F1). Analyse par imagerie du faisceau pyramidal par tractographie en tenseur de diffusion chez 2 hommes adultes SK + MM + ANOS1 + analyse anatomopathologique d’un fœtus ANOS1 + (ITG pour agenesie renale bilaterale). Resultats Presence d’un rearrangement complexe d’ANOS1 (C2067-2070AGGA > TCCT ; pGlu642Alafs21) chez les hommes SK + MM + et les femmes MM + de la famille F1. Absence de decussation des faisceaux pyramidaux chez 2 patients SK + MM + ANOS1 + (mutation nonsense c.773G > A ; p.TRP258X, et c.784C > T ; p.Arg262X) Hypoplasie du faisceau pyramidal chez un fœtus ANOS1 + (c.769C > T, p.R257X). Conclusion Les mutations perte de fonction d’ANOS1 peuvent etre associees a des mouvements en miroir avec transmission dominante chez les femmes. Les patients ANOS1 + avec MM ont un defaut de decussation des voies pyramidales. L’anosmine, codee par ANOS1, dont la fonction dans le developpement du bulbe olfactif et la migration des neurones olfactifs etait connue, participe egalement au developpement du faisceau pyramidal.

A case of a chondroblastoma of the skull-base associated with a persistent hypoglossal artery (PHA) is presented. Neuroradiological findings of the PHA and the tumour are reported. The existence of a carotico-basilar communication such as a PHA should be recognized prior to skull base surgery because of the potential risk of cerebral ischemia.