Comparison of fast field-cycling magnetic resonance imaging methods and future perspectives

This article is based upon work from COST Action CA15209, supported by COST (European Cooperation in Science and Technology). M. Bödenler, C. Gösweiner and H. Scharfetter acknowledge the financial support by the European Commission in the frame of the H2020 Future and Emerging Technologies (FET-open) under grant agreement 665172, project ‘CONQUER’. L. de Rochefort acknowledges the France Life Imaging network (Grant ANR-11-INBS-0006) that partially funded the small animal FFC-MRI system. D.J. Lurie, L.M. Broche and P.J. Ross acknowledge funding from the European Union’s H2020 research and innovation programme under grant agreement No 668119, project ‘IDentIFY’.Peer reviewedPublisher PD

Validity, Reliability, and Differential Item Functioning of English and French Versions of the 10-Item Connor-Davidson Resilience Scale in Systemic Sclerosis: A Scleroderma Patient-Centered Intervention Network Cohort Study

Objective Some individuals with systemic sclerosis (SSc) report positive mental health, despite severe disease manifestations, which may be associated with resilience, but no resilience measure has been validated in SSc. This study was undertaken to assess the validity, reliability, and differential item functioning (DIF) between English- and French-language versions of the 10-item Connor-Davidson Resilience Scale (CD-RISC-10) in SSc. Methods Eligible participants were enrolled in the Scleroderma Patient-centered Intervention Network Cohort and completed the CD-RISC-10 between August 2022 and January 2023. We used confirmatory factor analysis (CFA) to evaluate the CD-RISC-10 factor structure and conducted DIF analysis across languages with Multiple Indicators Multiple Causes models. We tested convergent validity with another measure of resilience and measures of self-esteem and depression and anxiety symptoms. We assessed internal consistency and test–retest reliability using Cronbach\u27s alpha and intraclass correlation coefficient (ICC). Results A total of 962 participants were included in this analysis. CFA supported a single-factor structure (Tucker–Lewis index = 0.99, comparative fit index = 0.99, root mean square error of approximation = 0.08 [90% confidence interval (90% CI) 0.07, 0.09]). We found no meaningful DIF. Internal consistency was high (α = 0.93 [95% CI 0.92, 0.94]), and we found that correlations with other measures of psychological functioning were moderate to large (|r| = 0.57–0.78) and confirmed study hypotheses. The scale showed good 1–2-week test–retest reliability (ICC 0.80 [95% CI 0.75, 0.85]) in a subsample of 230 participants. Conclusion The CD-RISC-10 is a valid and reliable measure of resilience in SSc, with score comparability across English and French versions

A Solve-RD ClinVar-based reanalysis of 1522 index cases from ERN-ITHACA reveals common pitfalls and misinterpretations in exome sequencing

Purpose Within the Solve-RD project (https://solve-rd.eu/), the European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies aimed to investigate whether a reanalysis of exomes from unsolved cases based on ClinVar annotations could establish additional diagnoses. We present the results of the “ClinVar low-hanging fruit” reanalysis, reasons for the failure of previous analyses, and lessons learned. Methods Data from the first 3576 exomes (1522 probands and 2054 relatives) collected from European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies was reanalyzed by the Solve-RD consortium by evaluating for the presence of single-nucleotide variant, and small insertions and deletions already reported as (likely) pathogenic in ClinVar. Variants were filtered according to frequency, genotype, and mode of inheritance and reinterpreted. Results We identified causal variants in 59 cases (3.9%), 50 of them also raised by other approaches and 9 leading to new diagnoses, highlighting interpretation challenges: variants in genes not known to be involved in human disease at the time of the first analysis, misleading genotypes, or variants undetected by local pipelines (variants in off-target regions, low quality filters, low allelic balance, or high frequency). Conclusion The “ClinVar low-hanging fruit” analysis represents an effective, fast, and easy approach to recover causal variants from exome sequencing data, herewith contributing to the reduction of the diagnostic deadlock

Diffusion de l'hélium-3 hyperpolarisé dans le tissu pulmonaire (évaluation par différentes techniques IRM)

Ce travail présente une étude expérimentale sur l effet de la diffusion restreinte de l hélium-3 hyperpolarisé dans l acinus pulmonaire effectuée à bas champ magnétique 0,1 T. Plusieurs fantômes avec différentes tailles et connections modélisant l acinus humain sain et à un stade précoce de l emphysème ont été réalisés selon le modèle de Kitaoka. L'atténuation du signal dévie par rapport au comportement prévu de décroissance exponentielle en G2, G étant l'intensité de gradient. Cette observation indique une certaine ambiguïté sur la possibilité de quantifier de façon absolue le coefficient de diffusion apparent (ADC), sauf dans la limite G faible. Des simulations Monte-Carlo sont en bon accord avec les mesures. Des séquences originales rapides basées sur le principe des échos de spin multiples ont été développées, pour accéder à une valeur globale d ADC à des temps longs permettant l exploration du gaz dans toute la structure de branchement de l'acinus. Des mesures sur un modèle animal d emphysème (rat) ont été comparées à des cartes obtenues à partir d acquisitions standard avec petits angles de basculement, elles indiquent une augmentation systématique et toujours significative des ADC par rapport au contrôle sain, pour plusieurs protocoles de mesure. La méthode globale a une meilleure sensibilité que la cartographie standard, en outre elle donne un plus fort contraste d ADC entre animaux sains et avec emphysème du fait de la possibilité d employer des valeurs de G plus faibles. Ces outils de mesure de diffusion par IRM et RMN des gaz hyperpolarisés ouvrent des voies prometteuses aussi bien pour la physique de la diffusion que pour les applications médicales.This work presents an experimental study on restricted diffusion of hyperpolarized helium-3 in the pulmonary acinus carried out at a low magnetic field of 0.1 T. Several phantoms with various sizes and connections modeling the human acinus, either healthy or at an early stage of emphysema, were realized according to the Kitaoka model. Signal attenuation showed deviation from the expected exponential decay in G2, G being the gradient intensity. This observation indicated a certain ambiguity on the possibility of absolute quantification of the apparent diffusion coefficient (ADC), except within the limit of weak G. Monte Carlo simulations were in agreement with measurements. Original fast sequences based on multiple spin echoes were developed, to get a global ADC value at long times informing on the exploration of gas in the whole acinus branching structure. Measurements on an animal model of emphysema (rat) were compared to maps obtained from standard acquisitions with small flip angles, they indicated a systematic ADC increase which was always significant as compared to healthy controls, for several measurement protocols. The global method has a better sensitivity than the standard cartography; moreover it gives a stronger ADC contrast between healthy animals and emphysematous ones, because of the possibility of employing lower G values. These tools of diffusion measurement by MRI and NMR of hyperpolarized gases open promising ways for the physics of diffusion as well as for medical applications.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Influence de l'intensité du champ magnétique sur l'imagerie RMN des poumons à l'aide d'hélium-3 hyperpolarisé

Les maladies pulmonaires obstructives chroniques sont la quatrième cause de mortalité en Europe. Les techniques disponibles pour les suivre ne permettent de diagnostiquer la maladie que tardivement. Une nouvelle méthode a été proposée en 1994: l'imagerie par résonance magnétique (IRM) avec des gaz hyperpolarisés (HP). Les poumons constituent un immense interface entre le gaz et le tissu. Dans un champ magnétique (B0, la différence de susceptibilité magnétique entre les deux milieux a pour conséquence de détériorer le signal. Cet effet est d'autant plus fort que B0 est élevé. Ayant à notre disposition deux appareils à deux B0 différents (0,1T et 1,5T) ainsi qu'un système de pompage optique pour produire de l'hélium-3 (3He) HP, nous avons étudié quantitativement l'influence de B0 sur le signal de l'3He HP dans les poumons. Dans un premier temps les bases théoriques et la liste exhaustive des matériels nécessaires pour cette étude ont été présentées. Puis nous avons mis en évidence que le temps de relaxation transversale de l'3He HP lors de l'application d'un train d'échos de spins, T2cpmg, s'allonge lorsque B0 décroît. Une variation de deux ordres de grandeur a été observée entre 0,1 et 1,5 T. Des études sur modèle animal (rat) ont montré que d'une pan T2cpmg a une sensibilité au remplissage pulmonaire équivalente à celle du coefficient apparent de diffusion, et d'autre pan l'ajout d'un agent super paramagnétique provoque la compensation de l'effet de susceptibilité. Nous avons ensuite mis en évidence le rallongement du temps de vie du signal de l'hélium-3 HP dans les poumons, T2*, à faible B0. Enfin une comparaison du rapport signal sur bruit mesuré sur les deux appareils a été entreprise. En conclusion bien que le rallongement de T2* à faible B0 soit bénéfique pour l'IRM, cet effet est limité et l'utilisation d'appareil classique haut champ ne représente pas un inconvénient déterminant pour cette application.The chronic obstructive pulmonary disease are the forth cause of mortality in Europe. The available techniques only give a late assessment in the disease process. A new technique has been proposed in 1994: The magnetic resonance imaging (MRI) of hyperpolarized (HP) gases. The lungs are a large interface between gas and tissue. In a magnetic field (B0), the difference of magnetic susceptibility between both medias decays the signal. This effect increases with B0. We have two scanners with two different B0 (0.1 T and 1.5 T) and optical pumping system to produce hyperpolarized helium-3 (3He) so we studied quantitatively the influence of B0 on the 3He HP in the lungs. First, the needed theoretical bases and an exhaustive list of materials to carry out this study were presented. Then we have observed that the transverse relaxation time of HP 3He for a spin echo train sequence, T2cpmg, increases when B0 decreases. A two decade magnitude variation has been observed between 0.1 T and 1.5 T. Some studies on animal model (rat) have shown that T2cpmg has sensitivity to the lung filling which is equivalent to the apparent diffusion coefficient, and that the injection of a super paramagnetic the lung susceptibility effect can be matched. We also measured an increase of the time life of the signal of HP 3He, T2*, in the lungs for lower B0. Afterward we compare the signal to noise ratio (SNR) on the both scanners. In conclusion even if the T2* increasing at low B0 is good for SNR, this effect is limited and the use of classic high field scanner is not an inconvenient for this application.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Elaboration de pseudosubstrats accordables en paramètre de maille à base de silicium mésoporeux pour l'hétéroépitaxie

Ce travail de thèse évalue les potentialités du Silicium Poreux (SiP) nanostructuré comme substrat générateur de contraintes mécaniques pour modifier le paramètre de maille d une fine couche de semiconducteur IV-IV (Si ou SiGe) qui lui est associée. Le but est soit d ajuster les propriétés optoélectroniques de la couche en la contraignant, soit d accorder son paramètre de maille à celui d un autre matériau (Si1-xGex, Ge ou GaAs). Utilisée comme couche germe pour une reprise d épitaxie, cette couche mince peut permettre l obtention d un matériau de bonne qualité cristalline. L hétérostructure (couche mince) / (Si poreux) constitue ainsi un pseudosubstrat accordable en paramètre de maille fabriqué à partir d un substrat peu onéreux, le Si Poreux. La mise au point d une nouvelle technique dite de la double plaque a permis de franchir un verrou technologique majeur et d obtenir des couches de semiconducteur IV-IV (Si ou SiGe), sans défauts structuraux, ultrafines et d épaisseur rigoureusement constante (~50 nm), de grandes dimensions latérales (2"), et présentant une surface peu rugueuse et exempte de toute pollution. Cette couche ultrafine est facilement manipulable et sa dimension latérale n est limitée que par les dimensions de la cellule d anodisation utilisée. L oxydation thermique à basse température du substrat de Si mésoporeux induit son expansion volumique et permet la déformation contrôlée des couches de Si et de SiGe. Le contrôle des paramètres du procédé permet d atteindre des déformations importantes, excédant 1%, tout en évitant la formation des défauts structuraux. Cette technique a permis de rapprocher le paramètre de maille dans le plan du film de celui du Ge et du GaAs et donc de faire un pas en direction de leur intégration sur silicium.This work assesses the potentiality of Porous Silicon (PS) as a mechanical straining substrate for modifying the lattice parameter of IV-IV semiconductor thin films (Si or SiGe). The aim is either to tune the optoelectronic properties of the thin film, or to adapt the film lattice parameter to that of other materials like SiGe, Ge, or GaAs. Such a film can be used as a seed layer for the heteroepitaxial growth of lattice mismatched materials such as SiGe, Ge or GaAs on silicon with a high crystalline quality. In short, the (thin film) / (porous silicon) heterostructure constitutes a lattice tunable virtual substrate obtained from a low cost substrate, viz, the porous silicon. The development of a two wafers technique has been a true breakthrough as it made it possible to obtain a IV-IV semiconductor film as thin as 50 nm, with large lateral dimension (2"), strictly constant thickness, exempt of structural defects and with a perfectly smooth and clean surface. Moreover, this ultra-thin film can be easily handled and its lateral dimension is only dependant on the diameter of the anodization cell. Low temperature thermal oxidation of the bulk porous Si substrate induces its volume expansion, which leads to a straining of the thin film on top. The control of oxidation parameters allows obtaining highly strained (above 1%) films without any structural defects. The technique makes the film lattice in-plane parameter closer to that of Ge or GaAs, which is a step forward toward their integration on silicon.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

Measurement of R2 dispersion profiles using Fast Field Cycling MRI

International audienceFast Field Cycling (FFC) MRI enables rapid and precise relaxometry measurements as a function of magnetic field B_\textrm0. Up to now, it was possible to measure longitudinal R_\textrm1-NMRD profiles and to generate innovative R_\textrm1-dispersive contrasts. However, the ability to measure transverse R_\textrm2-NMRD profiles has still to be investigated. Here, a spin-echo based FFC sequence is developed to measure R_\textrm2-dispersion, and is applied to ferritin and Gd-DOTA in the range 1.15 to 1.85 T. It is shown that measurements of R2 dispersion could be obtained accurately with the FFC-MRI technology

DQF-MT MRI of connective tissues: application to tendon and muscle

Object The sequence combining DQF (double quantum filtering) with magnetisation transfer (DQF-MT) was tested as an alternative to the DQF sequence for characterising tendon and muscle by MR imaging. Materials and methods DQF-MT images of tendon–muscle phantoms were obtained at 4.7 T using ultra-short time to echo (UTE) methods in order to alleviate the loss of SNR due to the short T2 of the tissues. Two different sampling schemes of the k-space, Cartesian or radial, were employed. In vivo images of the human ankle on a clinical 1.5 T scanner are also presented. Parameters providing optimal tendon signal as well as optimal contrast between this tissue and muscle were determined. Results Two sets of parameters resulting in different contrasts between the tissues were found. For the first set (short creation time τ = 10 μs and magnetisation exchange time tLM = 100 ms), DQF-MT signals in muscle and tendon were detected, with that of the tendon being the larger one. For the second set (long creation time τ = 750 μs and magnetisation exchange time 10 μs < tLM < 100 ms), the DQF-MT signal was detected only in the tendon, and the decay of the double quantum coherence was slower than that observed for the first one, which allowed us to acquire DQF-MT MR images on a clinical 1.5 T MR scanner with minimal software interventions. In favourable conditions, the DQF-MT signal in the tendon could represent up to 10 % of the single-quantum signal. Conclusion Dipolar interaction within macromolecules such as collagen and myosin is at the origin of the DQF-MT signal observed in the first parameter set. This should enable the detection of muscle fibrosis

Complexity, a sensory driver of consumer perceived quality

Complexity, a sensory driver of consumer perceived quality. 5. European conference on sensory consumer science of foods and beverages. A sense of inspiratio

Dermatophytose du chanfrein chez un fox-terrier

National audienceUn fox-terrier âgé de deux ans présente une dermatite prurigineuse, avec une alopécie localisée au chanfrein qui évolue depuis un an sans répondre aux traitements symptomatiques. La culture mycologique révèle la présence du dermatophyte Trichophyton mentagrophytes var. erinacei. A l’issue de deux mois de traitement antifongique systématique et topique, une guérison clinique et mycologique est obtenue. Comme dans le cas décrit, cette infection se traduit classiquement par l’apparition d’une lésion cutanée unique, alopécique, légèrement squameuse et localisée sur la face. En l’absence de traitement antifongique, cette lésion peut persister pendant plusieurs mois. La contagion aux autres animaux domestiques ou à l’homme semble exceptionnelle. Le traitement est classique et le pronostic est bon