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Cangrelor is an intravenous P2Y12 receptor inhibitor with a rapid onset/offset of action and a short half-life (3–6 min). The objective was to present a preliminary experience regarding the safety and effectiveness using cangrelor, in combination with aspirin, in acute ischemic stroke patients requiring acute stenting. Retrospective analysis for patients who underwent stenting (intracranial and/or extracranial) in the setting of acute ischemic stroke with cangrelor and aspirin as antiplatelet therapy. Cangrelor was used in 12 patients, 4 (33%) with extracranial stenting, 6 (50%) with intracranial stenting and 2 (17%) with combined extracranial and intracranial stenting. The mean age was 67 years (44–88) and 9 patients (75%) were female. The median National Institutes of Health Stroke Score at admission was 15 (IQR: 8–22). Of the patients, six (50%) received intravenous thrombolysis. All patients (100%) obtained modified thrombolysis in cerebral infarction score ≥2b. Good clinical outcome, defined as modified Rankin scale score ≤2 at 3‑months follow-up, was observed in 7 patients (58%). None of the patients experienced intraprocedural thromboembolic complications. Postprocedural stent thrombosis after cessation of cangrelor infusion due to emergency craniotomy surgery to manage malignant cerebral infarction occurred in one patient (8%). Of the patients, two (17%) experienced asymptomatic intracranial hemorrhage (ICH), one patient (8%) experienced symptomatic ICH and one (8%) retroperitoneal hematoma was observed, which was managed conservatively. Cangrelor might be a safe and effective antiplatelet medication owing to its on/off activity for acute stenting in the setting of acute ischemic stroke. Further investigations through randomized studies with larger samples are necessary.

International audience; PURPOSE : Most recent guidelines recommend the use of stent retriever devices in endovascular treatment of acute ischemic stroke with large vessel occlusion (LVO). Recently published data reported convincing results with thromboaspiration devices such as the Penumbra System (Penumbra, Alameda, CA, USA) combined with supple reperfusion catheters by using the ADAPT (A Direct Aspiration First-Pass Thrombectomy) technique. The aim of this study was to report our initial experience with the 3MAX (3.8 F) reperfusion catheter for the recanalization of distal intracranial arteries.METHODS : From August 2015 to December 2016, 32 consecutive patients (16 females, 50%; mean age = 67.4 ± 18.7 years, range: 22-91) for 38 distal occlusions underwent mechanical thrombectomy (MT) by thromboaspiration using the 3MAX. Median NIHSS score at admission was 14 (IQR: 9-19). Distal occlusions were distributed as follows: M2 (n: 23), M3 (n: 6), P1 (n: 3), P2 (n: 2), P3 (n: 2), A3 segment (n: 1) and superior cerebellar artery (n: 1).RESULTS : In 1/38 (2.6%) target artery, the 3MAX could not be navigated. Of the 37 (59.5%) remaining arteries, 22 were successfully reperfused (TICI 2b/3) after ADAPT with the 3MAX alone. Additional stent retriever thrombectomy allowed a 76.3% final reperfusion rate. Good functional outcome (mRS ≤2) was obtained in 45.5% of patients at 3 months. Three (9.4%) 3MAX-related complications occurred: 2 emboli to new territory (ENT) and one vascular perforation.CONCLUSIONS : The 3MAX is well-navigable in distal arteries making it useful as a frontline technique. However, the reperfusion rate with the 3MAX catheter alone seems lower than the ones reported with stent retrievers for such distal occlusions.

International audience; Epileptic syndromes are distinctive disorders with specific features, which when taken together, permit a specific diagnosis. There is actually a debate on that medial temporal lobe epilepsy with hippocampal sclerosis is an epileptic syndrome. To address this issue, we searched for discriminative semiological features between temporal lobe epilepsy patients with hippocampal sclerosis (TLE-HS patients or group 1), TLE patients with medial structural lesion other than hippocampal sclerosis or in MRI-negative cases with medial onset on further investigations (group 2) and lateral TLE patients (LTLE or group 3). We retrospectively collected data from medical and EEG-video records of 523 TLE patients, referred for surgery to the Pitié-Salpêtrière Epileptology Unit between 1991 and 2014. We identified 389 patients belonging to group 1, 61 patients belonging to group 2, and 73 patients belonging to group 3 and performed a comparative analysis of their clinical data and surgical outcomes. TLE-HS patients (group 1): (1) began epilepsy earlier (11 ± 9 vs. 20 ± 10 vs. 15 ± 9 years); (2) exhibited more frequently early febrile convulsions (FC) (59 vs 7 vs 5%); (3) presented more: ictal gestural automatisms (90 vs 54 vs 67%), dystonic posturing (47 vs 20 vs 23%), and secondary generalized tonic–clonic seizures (GTCS) (70 vs 44% vs 48%) as compared to both groups 2 and 3 patients (all p < 0.001). With respect to auras, abdominal visceral auras were more reported by TLE-HS than by LTLE patients (49 vs 16%). Three cardinal criteria correctly classified 94% of patients into TLE-HS group: history of FC, dystonic posturing, and secondary GTCS. Postoperative outcome was significantly better in TLE-HS group than in the two other groups (p = 0.03 and 0.003). Our study demonstrates that cardinal criteria are reliably helpful to distinguish patients with TLE-HS from those with other TLE and may allow considering TLE-HS as a distinctive syndrome.

International audience; Most cochlear implantations are unilateral. To explore the benefits of a binaural cochlear implant, we used water-labelled oxygen-15 positron emission tomography. Relative cerebral blood flow was measured in a binaural implant group (n = 11), while the subjects were passively listening to human voice sounds, environmental sounds non-voice or silence. Binaural auditory stimulation in the cochlear implant group bilaterally activated the temporal voice areas, whereas monaural cochlear implant stimulation only activated the left temporal voice area. Direct comparison of the binaural and the monaural cochlear implant stimulation condition revealed an additional right temporal activation during voice processing in the binaural condition and the activation of a right fronto-parietal cortical network during sound processing that has been implicated in attention. These findings provide evidence that a bilateral cochlear implant stimulation enhanced the spectral cues associated with sound perception and improved brain processing of voice stimuli in the right temporal region when compared to a monaural cochlear implant stimulation. Moreover, the recruitment of sensory attention resources in a right fronto-parietal network allowed patients with bilateral cochlear implant stimulation to enhance their sound discrimination, whereas the same patients with only one cochlear implant stimulation had more auditory perception difficulties.

International audience; INTRODUCTION: The clinical efficacy of thrombolysis in stroke patients is explained by the increased rate of recanalization, which limits infarct growth. However, the efficacy could also be explained by the protection of specific sites of the brain. Here, we investigate where is this outcome-related tissue at risk using voxel-based analysis. METHODS: We included 68 acute stroke patients with middle cerebral artery (MCA) occlusion on the admission MRI performed within 6 h of symptoms onset (H6) and 16 controls. MCA recanalization was assessed using the magnetic resonance angiography performed at day 1 (D1). Apparent diffusion coefficient (ADC) changes were analyzed using a voxel-based method between patients vs. controls group at admission (H6) in non-recanalized vs. recanalized and in 3-month poor vs. good outcome patients at D1. RESULTS: Complete or partial MCA recanalization was observed in 52 of 68 patients. Good outcome at 3 months occurred in 40 patients (59%). In non-recanalized patients, ADC was decreased in the deep MCA and watershed arterial territory (the lenticular nucleus, internal capsule, and the overlying periventricular white matter). This decrease was not observed in recanalized patients at D1 or patients at H6. Fiber tracking suggested that the area is crossed by the cortico-spinal, cerebellar, and intra-hemispheric association tracts. Finally, this area almost co-localized with the area associated with poor outcome. CONCLUSIONS: A clinically relevant area of tissue at risk may occur in patients with MCA infarcts at the level of deep white matter fiber tracts. These findings suggest that neuroprotection research should be refocused on white matter.

Les essais ayant permis de demontrer l’efficacite de la thrombolyse intraveineuse n’ont inclus que tres peu d’octogenaires alors que ces derniers representent une fraction croissante des patients hospitalises dans les unites neurovasculaires. Tous les registres publies montrent que la mortalite postthrombolyse est environ trois fois plus importante chez les octogenaires que chez les sujets plus jeunes et la recuperation sans sequelle deux fois moins frequente, ce qui est egalement le cas des patients non thrombolyses. Par contre, l’augmentation du risque d’hemorragie symptomatique (HS) n’atteint pas le seuil de significativite statistique. Ces resultats sont retrouves dans notre serie de 457 patients dont 85 etaient octogenaires. Ce registre montre aussi que l’impact de la gravite neurologique sur le pronostic est plus marque chez les sujets âges que chez les sujets plus jeunes. De ce fait, chez les octogenaires, le pronostic de la thrombolyse, qui est bon dans les accidents ischemiques cerebraux (AIC) de severite moderee (NIHSS < 15), devient franchement catastrophique lorsque le NIHSS initial est superieur a 23, ce qui pose le probleme de la justification de ce traitement dans ce cas de figure.

There is considerable debate over the size and direction of the non-adiabatic component of the spin-torque generated when a current flows across a domain wall in a ferromagnet. Measurements of this property in a wall just 1–10 nm wide suggest its value is small, arising from purely magnetic dissipation mechanisms. Torques appear between charge carrier spins and local moments in regions of ferromagnetic media where spatial magnetization gradients occur, such as a domain wall, owing to an exchange interaction. This phenomenon has been predicted by different theories1,2,3,4,5,6,7 and confirmed in a number of experiments on metallic and semiconductor ferromagnets8,9,10,11,12,13,14,15,16,17,18,19. Understanding the magnitude and orientation of such spin-torques is an important problem for spin-dependent transport and current-driven magnetization dynamics, as domain-wall motion underlies a number of emerging spintronic technologies20,21. One outstanding issue concerns the non-adiabatic spin-torque component β, which has an important role in wall dynamics, but no clear consensus has yet emerged over its origin or magnitude. Here, we report an experimental measurement of β in perpendicularly magnetized films with narrow domain walls (1–10 nm). By studying thermally activated wall depinning, we deduce β from the variation of the Arrhenius transition rate with applied currents. Surprisingly, we find β to be small and relatively insensitive to the wall width, which stands in contrast to predictions from transport theories2,5,6,7. In addition, we find β to be close to the Gilbert damping constant α, which, in light of similar results on planar anisotropy systems15, suggests a universal origin for the non-adiabatic torque.

The so called "neurodegenerative Langerhans cell histiocytosis" (ND-LCH) is a rare and severe complication of LCH presenting as a progressive cerebellar ataxia associated with pyramidal tract signs, and cognitive impairment. MRI is the gold standard to investigate CNS lesions of ND-LCH but little is known about functional changes observed in this disease. To search for CNS metabolic changes in NDLCH. Seven patients suffering from ND-LCH were investigated by 18F-FDG PET in this prospective study and compared with 21 healthy controls. ND-LCH patients demonstrated recurrent abnormalities including bilateral hypometabolism in the cerebellum, the basal ganglia (caudate nuclei), frontal cortex and, bilateral, a relatively increased metabolism in the amygdalae (p < 0.001). Functional changes in these anatomical regions may be detected in the absence of any apparent lesion on MRI. ND-LCH demonstrates a recurrent 18F-FDG PET metabolic signature. Our results suggest that 18F-FDG PET might be a useful tool for an early diagnosis of ND-LCH before neuroradiologic abnormalities appear.

International audience; The recent advent of new functional neuroimaging techniques such as functional magnetic resonance imaging (fMRI) makes it possible to examine cerebral activations in healthy individuals. In the present study, we attempted to examine the anatomical distribution of neocortical and mediotemporal activations in control subjects during episodic memory tasks over 24 h. BOLD (blood oxygenation-level-dependent) fMRI data were collected from 10 control subjects. Twenty-two contiguous images covering the whole brain were acquired using an EPI echoplanar sequence. Subjects were instructed to learn a list of 17 words, and to recall it immediately and after a 24-h interval. Individual and group analyses were performed using SPM96. The results demonstrated that a similar left occipito-temporofrontal network was activated during both immediate and 24-h-delayed retrieval conditions. In addition, the 24-h-delayed retrieval also activated a larger parietal region and the right hippocampus. These findings suggest that fMRI is a reliable method with which to perform anatomical studies.

We evaluated the feasibility and use of diffusion-weighted and fluid-attenuated inversion-recovery pulse sequences performed as an emergency for patients with acute ischaemic stroke. A 5-min MRI session was designed as an emergency diagnostic procedure for patients admitted with suspected acute ischaemic stroke. We reviewed routine clinical implementation of the procedure, and its sensitivity and specificity for acute ischaemic stroke over the first 8 months. We imaged 91 patients (80 min to 48 h following the onset of stroke). Clinical deficit had resolved in less than 3 h in 15 patients, and the remaining 76 were classified as stroke (59) or stroke-like (17) after hospital discharge. Sensitivity of MRI for acute ischaemic stroke was 98 %, specificity 100 %. MRI provided an immediate and accurate picture of the number, site, size and age of ischaemic lesions in stroke and simplified diagnosis in stroke-like episodes. The feasibility and high diagnostic accuracy of emergency MRI in acute stroke strongly support its routine use in a stroke centre.

Longitudinal positron emission tomography (PET) studies of 6-18F-L-dopa uptake in the striatum are used to assess the progression of Parkinson's disease or the survival of neuronal cells grafted in parkinsonian patients. These studies are performed over several years, and data analysis may suffer from the change from old tomographs to new machines with better sensitivity and spatial resolution. Furthermore, such studies on parkinsonian patients may be accomplished in either 2D or 3D acquisition mode. The aforementioned improvements offer great benefits for the study of neurodegenerative diseases, especially those affecting the striatum. However, direct comparison of data is not straightforward owing to variation in scanner characteristics. In this study, we assessed the feasibility of comparing the 6-18F-L-dopa striatal uptake values (Kc) measured in two groups of healthy subjects using two tomographs of different generations. We re-studied and compared acquisitions performed on 14 healthy subjects using 6-18F-L-dopa. Half of these studies had been performed in 2D acquisition mode using an ECAT 953B. The other half had been performed in 3D acquisition mode using an ECAT EXACT HR+. Different reconstruction protocols were used and the Kc values obtained were statistically compared. The results showed that lowering the transverse spatial resolution of images obtained with the scanner having the better spatial resolution, so that it more closely matched that of the other machine, allowed similar KC values to be obtained in healthy subjects. This study shows that quantitative results of 6-18F-L-dopa scans can be matched between different scanners with different intrinsic resolutions. This can be accomplished using adequate modifications of the reconstruction parameters. Such modifications can be used to help in the longitudinal monitoring of parkinsonian patients using different tomographs.

It is demonstrated that perpendicular magnetic anisotropy may be obtained with a room temperature growth process in ordered (FePd) alloys. Indeed, using atomic layer by atomic layer epitaxy, a partial chemical ordering into the L10 structure is obtained, with a corresponding intermediate perpendicular anisotropy (\(({K_u}/2\pi M_s^2 \sim 0.4)\)). These samples provide an appropriate template for the study of the magnetic reorientation from in plane to out of plane magnetization upon layer's thickness increase. VSM, transverse Kerr measurements and magnetic force microscopy have been used in order to determine the relevant magnetic parameters and the occurrence of the reorientation transition.

A 76-year old woman was affected by lethargic encephalitis in 1918, at the age of 3 months. Long-term clinical follow-up with late neuropsychological evaluation revealed post-encephalitic parkinsonism, which worsened very slowly and was improved by levodopa. Obsessive and compulsive disorders (OCD) were associated to nosophobia. Neuropsychological evaluation showed mild visuocontructional memory deficit, which was isolated. 18 Fluoro-Dopa PET demonstrated a severe bilateral and symmetrical reduction in fluoro-dopa uptake, which was more marked in the putamen than in the caudate. Thus, the pattern of dopaminergic denervation was similar to the one observed in idiopathic Parkinson's disease.

A semi-automatic method was developed to determine the anterior (AC) and posterior (PC) commissures on brain single-photon emission tomographic (SPET) perfusion images, and then to draw the proportional anatomical Talairach's grid on each axial SPET image. First, the AC-PC line was defined on SPET images from the linear regression of four internal landmarks (frontal pole of the brain, inferior limit of the anterior corpus callosum, sub-thalamic point and occipital pole). Second, the SPET position of AC and PC points on the AC-PC line was automatically determined from measurements made on hard copies of magnetic resonance (MR) images of the patients. Finally, a proportional Talairach's grid was automatically drawn on each axial SPET image. To assess the accuracy of localization of AC and PC points, co-registered technetium-99m hexamethylpropylene amine oxime SPET and MR images from 11 subjects were used. The mean displacements between estimated points on SPET and true points on MRI (Deltax=sagittal, Deltay=frontal and Deltaz=axial displacement) were calculated. The mean displacements (in mm) were Deltax=-1.4+/-1.8, Deltay=-1.7+/-3.3 and Deltaz=-1. 1+/-2.5 for AC, and Deltax=-1.8+/-1.8, Deltay=0.3+/-3.2 and Deltaz=-1.3+/-2.7 for PC. These displacements represented an error of less than 5 mm at the anterior or posterior pole of the brain or at the vertex. Intra- and inter-observer comparisons did not reveal significant differences in mean displacements. Thus, this semi-automatic method results in reproducible and accurate stereotactic localization of SPET perfusion abnormalities. This method can be used routinely for repeat follow-up studies in the same subject as well as in different individuals without requiring SPET-MRI co-registration.

Acetyl-levo-carnitine (ALC) protects against 1-methyl, 4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced toxicity in the nonhuman primate. ALC pretreated monkeys do not show signs of parkinsonism or electroretinographic changes typical of dopaminergic deficiency when given MPTP. In addition, pilot neurochemical and morphological data confirm a partial protection effect. While MAO-B inhibitors, like L-Deprenyl, are thought to protect dopaminergic neurons from MPTP-induced cell death by preventing the conversion of MPTP to its toxic metabolite MPP+, ALC is not known to have MAO-B affinity. Converging evidence suggests that ALC may affect directly mitochondrial respiration, which is known to be the target of MPP+ and affected in human neurodegenerative diseases, including Parkinson's disease. The results of this study point to new therapeutic avenues for the treatment of these nosologic entities.

FePd(001) thin films have been grown by the molecular beam epitaxy (MBE) technique. At room temperature, these films are chemically disordered whereas at 350 °C a well ordered L10 structure is found with the c-axis oriented in the growth direction. By combining RHEED, STM and Auger measurements, it is suggested that ordering occurs at the growing surface by the development of bi-atomic steps of the ordered structure. We have put in evidence that the surfactant behavior of the Pd atoms is mainly involved in the ordering process and selects the single orientation of the c-axis. For intermediate temperatures between RT and 350 °C, TEM and X-rays have evidenced a pseudo-periodic arrangement of anti-phased domains having a columnar shape. The variation of the long-range order parameter is related to the average size of these ordered domains.

In order to identify the strain relaxation mechanism, Molecular Beam Epitaxy of wurtzite GaN on AlN was monitored in situ using Reflection High Energy Electron Diffraction (RHEED). In the substrate temperature range between 620°C and 720°C, a Stransky-Krastanov (SK) transition was evidenced, resulting in a 2D-3D transition after completion of 2 monolayers, with subsequent coalescence of 3D islands, eventually resulting in a smooth surface. Quantitative analysis of the RHEED pattern allowed us to determine that island formation is associated with elastic relaxation. After island coalescence, a progressive plastic relaxation is observed. The size and density of 3D islands was varied as a function of the growth parameters. AFM experiments revealed that the size of the GaN islands, about 8 nm large and 2 nm high, was small enough to expect quantum effects. It was found that capping of the islands by AlN resulted in a smooth surface after deposition of a few monolayers allowing us to grow a »superlattice» of islands by periodically repeating the process.

By controlling the Stranski-Krastanov growth mode of strained GaN deposited by molecular beam epitaxy on AlN, it is shown that islands with nanometric dimensions can be elaborated. The luminescence energy of the wetting layer is 4.6 eV, determined by cathodoluminescence experiments. The luminescence of dots with a mean size of 14 nm in diameter and 2nm in height is 3.8 eV and remains constant in intensity with increasing temperature, as an evidence of 0-dimension confinement effect. Theoretical analysis of the wetting layer luminescence energy is carried out, taking into account the non parabolicity in the conduction band.