Implantable NMR Microcoils in Rats: A New Tool for Exploring Tumor Metabolism at Sub-Microliter Scale?

The aim of this study was to evaluate the potential of a miniaturized implantable nuclear magnetic resonance (NMR) coil to acquire in vivo proton NMR spectra in sub-microliter regions of interest and to obtain metabolic information using magnetic resonance spectroscopy (MRS) in these small volumes. For this purpose, the NMR microcoils were implanted in the right cortex of healthy rats and in C6 glioma-bearing rats. The dimensions of the microcoil were 450 micrometers wide and 3 mm long. The MRS acquisitions were performed at 7 Tesla using volume coil for RF excitation and microcoil for signal reception. The detection volume of the microcoil was measured equal to 450 nL. A gain in sensitivity equal to 76 was found in favor of implanted microcoil as compared to external surface coil. Nine resonances from metabolites were assigned in the spectra acquired in healthy rats (n = 5) and in glioma-bearing rat (n = 1). The differences in relative amplitude of choline, lactate and creatine resonances observed in glioma-bearing animal were in agreement with published findings on this tumor model. In conclusion, the designed implantable microcoil is suitable for in vivo MRS and can be used for probing the metabolism in localized and very small regions of interest in a tumor

Antibody-targeting of ultra-small nanoparticles enhances imaging sensitivity and enables longitudinal tracking of multiple myeloma

Monitoring malignant progression and disease recurrence post-therapy are central challenges to improving the outcomes of patients with multiple myeloma (MM). Whereas current detection methods that rely upon bone marrow examination allow for precise monitoring of minimal residual disease and can help to elucidate clonal evolution, they do not take into account the spatial heterogeneity of the tumor microenvironment. As such, they are uninformative as to the localization of malignant plasma cells and may lead to false negative results. With respect to the latter challenge, clinically-available imaging agents are neither sufficiently sensitive nor specific enough to detect minute plasma cell populations. Here, we sought to explore methods by which to improve detection of MM cells within their natural bone marrow environment, using whole-animal magnetic resonance imaging to longitudinally monitor early-stage disease as well as to enhance tumor detection after systemic therapy. We conducted a proof-of-concept study to demonstrate that ultra-small

Functional Imaging: CT and MRI

SYNOPSIS: Numerous imaging techniques permit evaluation of regional pulmonary function. Contrast-enhanced CT methods now allow assessment of vasculature and lung perfusion. Techniques using spirometric controlled MDCT allow for quantification of presence and distribution of parenchymal and airway pathology, Xenon gas can be employed to assess regional ventilation of the lungs and rapid bolus injections of iodinated contrast agent can provide quantitative measure of regional parenchymal perfusion. Advances in magnetic resonance imaging (MRI) of the lung include gadolinium-enhanced perfusion imaging and hyperpolarized helium imaging, which can allow imaging of pulmonary ventilation and .measurement of the size of emphysematous spaces

Les coulisses d’une invention. Description expérientielle du processus d’invention technique

Behind the Scenes of an Invention. An experiential Description of the technical Invention Process. This paper describes the lived experience which accompanies the technical invention process. Explicitation interviews with inventors enabled us to identify a process which is iterative, recursive, composed of a macroprocess and micro-processes and structured around the permanent oscillation between several levels of awareness of the idea. The description of the micro-process’ stages led us to detect the “ pre-reflective” or “ unrecognized” strategies which accompany the genesis of a technical idea, which is nevertheless unpredictable. Inventors notably show two crucial skills : the ability to be attentive to their own lived experience and the ability to switch between several modes of attention.Cet article décrit l’expérience vécue qui accompagne le processus d’invention technique. La réalisation d’entretiens d’explicitation auprès d’inventeurs nous a permis d’identifier un processus itératif, récursif, composé d''un macroprocessus ainsi que de micro-processus créatifs et structuré autour de l''oscillation permanente entre plusieurs niveaux de conscience de l''idée. La description des étapes du micro-processus créatif nous a conduit à repérer les stratégies cognitives, en grande partie «pré-réfléchies » ou «non reconnues » , qui accompagnent la genèse d’une idée technique, aussi imprévisible cette genèse soit-elle. Les inventeurs interrogés témoignent notamment de deux savoir-faire cruciaux : savoir être attentif à son propre vécu et savoir alterner différents modes d''attention.Cremillieux Anne. Les coulisses d’une invention. Description expérientielle du processus d’invention technique. In: Intellectica. Revue de l'Association pour la Recherche Cognitive, n°61, 2014/1. Philosophie du Web et Ingénierie des Connaissances. pp. 273-310

Peut-on substituer l'échographie pleuro pulmonaire à la tomodensométrie thoracique en réanimation chirurgicale ?

BESANCON-BU Médecine pharmacie (250562102) / SudocSudocFranceF

Impact du debriefing sur l'amélioration des compétences techniques et non techniques lors de la simulation d'un arrêt cardiaque per opératoire

BESANCON-BU Médecine pharmacie (250562102) / SudocSudocFranceF

Polarisation d'hélium3 par la technique d'échange de spin et applications en IRM de la ventilation et de la perfusion pulmonaire

L'utilisation des gaz dits "hyperpolarisés" (HP) en (IRM) a permis le développement de nouvelles techniques d'imagerie. Le premier chapitre est consacré au dispositif de pompage optique de l'hélium3 par la méthode d'échange de spin que nous avons développé. Le deuxième chapitre présente un respirateur dédié au petit animal, compatible IRM et avec l'hélium3 HP que nous avons développé et avec lequel nous avons pu réaliser des images anatomiques de ventilation pulmonaire de haute résolution spatiale et temporelle. Le troisième chapitre est dédié à la perfusion pulmonaire utilisant de l'hélium3 HP et des agents de contraste sur petit animal (rat). Des images de perfusion ainsi que des cartes paramétriques du volume sanguin pulmonaire relatif (rPBV) ont été obtenues. Le dernier chapitre présente le développement de la séquence STEAM avec deux applications : la mesure des coefficients de diffusion apparent de l'hélium3 et l'imagerie pulmonaire de ventilation/perfusionLYON1-BU.Sciences (692662101) / SudocSudocFranceF

Etude descriptive transversale d'une cohorte d'enfants décédés d'une mort subite du nourrisson (analyse des facteurs étiologiques)

DIJON-BU Médecine Pharmacie (212312103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Développements méthodologiques pour l imagerie moléculaire dans le système cardiovasculaire et les noyaux polarisés par Résonance Magnétique Nucléaire

The research in Magnetic Resonance Imaging combining the proton molecular imaging and the hyperpolarized gases (helium-3) imaging is a promising way in the field of the cardiovascular and lung applications. In this context, the subjects of this thesis were to develop the instrumentations and to set up sequences and MR protocols dedicated to the small animal (mice) imaging for non-invasive longitudinal studies of the chronic cardiovascular and lung pathologies. The first chapter is dedicated to the vascular pathologies and the state of art of the knowledge of the MR contrast agents in cardiovascular and lung imaging. The second chapter is dedicated to the molecular imaging of the atherosclerosis plaque to evaluate new contrast agents: 1) non-specific, ex-vivo with a multi-spectral analysis of the atherosclerosis plaque components on human coronary arteries. 2) Specific, to asses the arterial wall inflammation in-vivo in ApoE-/- mice by targeting P-selectin (adhesion molecule expressed in an early stage of the pathology and atherothrombosis). In the third chapter, the real-time cardio-respiratory gating is described which was developed: 1) to study contrast agents of the atherosclerosis plaque in mice at the level of the aortic root and the carotids origin where atherosclerosis predominantly develops. 2) to enable non invasive evaluation of cardiac modifications induced by endurance exercise training in mice. The fourth chapter is dedicated to the pulmonary pathologies and the MRI with the hyperpolarized helium-3 to set up the ventilation lung imaging protocol under spontaneous mouse breathing conditions with fast MR sequences. The administration of the gas was accomplished by a mask allowing a non-invasive approach which is adapted to the longitudinal studies in mouseLYON1-BU.Sciences (692662101) / SudocSudocFranceF