Tesis sobre el tema "Perfusion techniques"
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Paolani, Giulia. "Brain perfusion imaging techniques". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Buscar texto completoFrancis, S. T. "Magnetic Resonance Imaging of perfusion : techniques and applications". Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243771.
Texto completoPerthen, Joanna Elizabeth. "Measurement of cerebral perfusion using magnetic resonance techniques". Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406739.
Texto completo王晴兒 y Ching-yee Oliver Wong. "Measurement of cerebrovascular perfusion reserve using single photon emission tomographic techniques". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31981677.
Texto completoWong, Ching-yee Oliver. "Measurement of cerebrovascular perfusion reserve using single photon emission tomographic techniques". Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19605328.
Texto completoFilipovic, Marina. "Application des techniques adaptatives à l'imagerie par résonance magnétique de perfusion". Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10030/document.
Texto completoMagnetic Resonance Imaging (MRI) requires tools for managing physiological and other motion of the patient. The generation of MR images consists of three steps: data acquisition with a pulse sequence, image reconstruction and image post-processing. Adaptive image reconstruction techniques aim at integrating motion information into the process of image generation from the acquired data, in order to compensate for motion-induced artefacts and problems. Dynamic contrast-enhanced (DCE) MRI is a technique designed for assessing the function of organs, by following dynamically the passage of a contrast agent in the body after a bolus injection. Motion-induced problems, especially in abdominal and thoracic DCE-MRI, consist of motion artefacts and misregistration. A new image reconstruction method, DCE-GRICS (Dynamic Contrast-Enhanced Generalized Reconstruction by Inversion of Coupled Systems), has been developed for solving these issues. Motion is estimated with a non rigid linear model based on physiological signals obtained from external sensors. Dynamic intensity changes caused by the passage of the contrast agent are described using a linear contrast change model based on B-splines. The method is applied and validated on myocardial perfusion imaging. Motion-induced inaccuracies in intensity-time curves are compensated, in order to allow for more reliable myocardial perfusion quantification by curve post-processing
Petric, Martin Peter. "Quantitative multi-slice cerebral perfusion imaging using arterial spin labelling MR techniques". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33821.
Texto completoMaredia, Neil. "Advanced techniques in first pass myocardial perfusion imaging by cardiac magnetic resonance". Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535669.
Texto completoSam, Mpaballeng Catherine. "Calibration of sap flow techniques in citrus using the stem perfusion method". Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/60855.
Texto completoDissertation (MSc (Agric))--University of Pretoria, 2016.
Plant Production and Soil Science
MSc (Agric)
Unrestricted
Ball, Daniel. "Development of novel hyperpolarized magnetic resonance techniques and compounds for perfused organs". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:21f6b661-cf21-46e7-9c7a-7c5d9ccf2b28.
Texto completoThomas, David Lee. "Magnetic resonance imaging of diffusion and perfusion : techniques and applications to cerebral ischaemia". Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391829.
Texto completoDiederich, Chris John 1960. "THE IMPLEMENTATION AND EVALUATION OF TWO THERMAL TECHNIQUES FOR MEASURING LOCAL TISSUE PERFUSION". Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/277137.
Texto completoWang, Haonan. "Novel Techniques for Rapid Cardiac Perfusion Magnetic Resonance Imaging with Whole Heart Coverage". BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6435.
Texto completoGerfault, Laurent. "Imagerie des produits de contraste ultrasonore : simulation et approche de la perfusion myocardique". Lyon, INSA, 2000. http://www.theses.fr/2000ISAL0041.
Texto completoLike other imaging modalities (MRI or X-Ray), ultrasound scanning has become a contrast imaging modality. It consists in the enhancement of standard ultrasound imaging using an intra-veinously injected ultrasound contrast agent (USCA). Video intensity and Doppler signals of perfused region, reached by the contrast agent, are enhanced. Then, contrast imaging allows a better visualization of perfusion of different organs, and the approach of functional imaging like myocardial perfusion study. In vitro efficiency of USCA has been demonstrated, but its in vivo use has shown a decrease of efficiency. This work studies the interactions between contrast agent and intra-corporal medium, and the influence of measurement method in the aims of understanding this lack of efficiency. The influences of intra-corporal medium actions (pulmonary filtering, dilution of USCA bolus, diffusion of internal gas of USCA micro particles cardiac pressure) and ultrasound waves are inspected to evaluate physical modifications of USCA in in-vivo conditions. The impact of these physical changes on acoustical responses of USCA is then studied. As clinical evaluation is performed on echographic images, simulations of echographic signals are computed. Finally, the feasibility of absolute measurement of blood flow rate is evaluated. A comparison between a newly developed fluid dynamics based model of bolus dilution and acoustical measurements made on a circulating tubular phantom is made. Our conclusions are applied to the study of myocardial perfusion using an isolated pig heart model
Ashooor, Habib. "First-pass techniques for the assessment of tissue perfusion using dynamic contrast-enhanced imaging". Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499907.
Texto completoArnold, J. R. "Evolving non-invasive techniques for the assessment of myocardial perfusion in ischaemic heart disease". Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543046.
Texto completoFreeman, Kendra D. "Microangiographic comparison of the effects of the three-loop pulley and six strand Savage tenorrhaphy techniques on the equine superficial digital flexor tendon". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/56839.
Texto completoMaster of Science
Parzy, Elodie. "Mise au point de techniques d'imagerie RMN par écho de spin rapide ou ultra-rapide adaptées à l'étude in vivo du petit animal". Paris 6, 2003. http://www.theses.fr/2003PA066471.
Texto completoKyriacou, Panayiotis A. "Investigation of new electro optical techniques for monitoring patients with compromised peripheral perfusion in anaesthesia". Thesis, Queen Mary, University of London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251876.
Texto completoThomassin-Naggara, Isabelle. "Etude des tumeurs annexielles du pelvis féminin en IRM fonctionnelle : mise au point des techniques et applications cliniques". Paris 11, 2008. http://www.theses.fr/2008PA112116.
Texto completoThe preoperative characterization of adnexal tumors is crucial for surgical care. Dynamic contrast enhanced MR imaging (DCE-MRI) allows an optimization of the tissue characterization. Adnexal tumors differ according to their dynamic curve enhancement, which reflect the immaturity of the vascular wall and the expression of VEGFR-2 on endothelial cells. For a quantitative analysis of enhancement, a turbo-FLASH sequence with high angles is better to get both optimal dynamic enhancement range and an almost linear relationship between the signal and the concentration of gadolinium. Initialization by a extended Kéty model stabilizes our two-compartmental model which allows the best description of exchanges between the capillary and the interstitial spaces. Using quantitative DCE MRI, malignant adnexal tumors display higher tissue perfusion and blood volume fraction than benign tumors. Finally, quantitative DCE-MRI is a suitable, non-invasive tool to assess physiological microvascular states and variations in normal myometrium, and could potentially be used to assess the role of the inner myometrium in assisted reproductive therapy
MacEwen, Clare. "Can data fusion techniques predict adverse physiological events during haemodialysis?" Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:1ef92d5d-920d-4ff4-b368-5e892527e675.
Texto completoVera, Pierre. "Optimisation de la détectabilité des anomalies de la perfusion cérébrale en tomographie d'émission monophotonique (Temp) : application à l'étude de l'épilepsie". Paris 11, 1999. http://www.theses.fr/1999PA11T012.
Texto completoDhermain, Frédéric. "Apports des techniques d'imagerie par résonance magnétique de perfusion dans la caractérisation et le suivi des gliomes cérébraux". Paris 11, 2010. http://www.theses.fr/2010PA115045.
Texto completoKay, Mark. "Evaluation of normothermic flush and perfusion techniques, using a novel normothermic preservation solution, in an isolated porcine haemoperfusion model". Thesis, University of Leicester, 2010. http://hdl.handle.net/2381/8326.
Texto completoZimmer, Fabian [Verfasser] y Lothar Rudi [Akademischer Betreuer] Schad. "Development of Arterial Spin Labeling Techniques for Quantitative Perfusion Measurements at 3 Tesla / Fabian Zimmer ; Betreuer: Lothar Rudi Schad". Heidelberg : Universitätsbibliothek Heidelberg, 2014. http://d-nb.info/1180031709/34.
Texto completoTroalen, Thomas. "IRM quantitative de la perfusion myocardique par marquage de spins artériels = Quantitative myocardial perfusion MRI using arterial spin labeling". Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM5006/document.
Texto completoMyocardial blood flow is an important factor of tissue viability and function. Diffuse changes in microcirculation preceding heart failure are involved in various cardiac pathologies. This work aim at improving existing techniques allowing quantitative and non-invasive myocardial perfusion assessment using arterial spin labeling. The first step of my work was to design an alternative approach to quantify myocardial blood flow in mice. The so called steady-pulsed ASL (spASL) is based on a regularly repeated pulsed labeling in order to build up a stationary regime of the magnetization under the influence of perfusion. The associated theoretical model has been developed in parallel to quantify tissue blood flow. We have shown that spASL allows to obtain similar results than the previously employed techniques, with the additional advantages of an increased sensitivity to the perfusion signal and a reduced acquisition time. A transfer towards clinical imaging for human applications was then undertaken. The spASL labeling scheme has been preserved while adapting the readout module to the specificities of cardiac MRI when applied to free-breathing human acquisitions. A dedicated post-processing, which includes a retrospective motion correction, has emerged subsequently to improve the robustness of our measurements. In parallel to the developments made for human studies, some optimization of the spASL technique when applied to rodent have been carried out depending on the conducted studies
Lecocq, Angèle. "Optimisation des techniques non invasives d'IRM de perfusion cérébrale et d'imagerie spectroscopique par résonance magnétique pour l'exploration des pathologies cérébrales". Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM5065.
Texto completoConventional MRI's lack of specificity in clinical routine limits our ability to perform correct diagnoses or follow-ups of pathological diseases. Two forms of NMR imaging, perfusion weighed and spectroscopic imaging provide information about two closely related characteristics :cerebral perfusion and metabolism. However, these techniques are not widely used due to the complexity of implementation and a lack of quantification.The general aim was to optimize and validate completely non-invasive NMR techniques for further human clinical applications in the context of exploring large cerebral volumes and determining absolute or pseudo-absolute quantification of cerebral perfusion and metabolism. Concerning perfusion, three arterial spin labeling sequences, PASL PICORE, PASL FAIR and pCASL, were compared in terms of sensitivity and reproducibility. The pCASL sequence was then integrated to a protocol applied to patients suffering from multiple sclerosis. In relation to metabolism, a protocol was applied in order to access absolute and pseudo-absolute metabolite quantification by water SI normalization from MRI proton density. This technique was validated on 2D CSI and then on 3D with EPSI sequence with two orientations, AC-PC and AC-PC+15 in order to generate reliable normative values of metabolites for the whole brain. The use of those spectroscopic techniques on patients suffering from multiple sclerosis allowed demonstrating the feasibility in clinic.This work demonstrates that reliable absolute quantification in perfusion weighted and spectroscopic imaging can be obtained with extensive coverage and with an acquisition time compatible with the reality of clinical exams
Djaoui, Fahima. "Quantification et systématisation 3D du débit sanguin cérébral à partir des images tomoscintigraphiques d'un traceur de perfusion à l'équilibre (HMPAO-TC99m,ECD-TC99m)". Université Louis Pasteur (Strasbourg) (1971-2008), 2003. http://www.theses.fr/2003STR13247.
Texto completoIn routine clinical studies it is certainly helpful to use non-invasive and simple techniques, to evaluate quantitatively the mean cerebral blood flow (CBF). Patlak graphical analysis approach, using intravenous radionuclide angiography with 99mTC-ECD or 99m TC-HMPAO, is a method witch does not require the determination of a specific compartment model, and based, only, on the evaluation of the unidirectional influx constant of the tracer across the blood brain barrier. The brain perfusion index, required to estimate the mean CBF, is calculated by standardisation of this influx rates value. The intra and inter observer variability studies indicates high reproducibility of this technique. However, after applying Lassen's correction algorithm to quantify SPECT images, the evaluation of regional CBF (rCBF) with conventional ROIs setting showed significant variability especially in inter-observer and for the pathological cases. This variability is due to many parameters like ROIs sizes, images selection and/or thickness, etc. To perform more precise results and less variability of cerebral perfusion quantification we have developed an original approach by constructing a 3D atlas of the systematisation of the brain vascularisation. This template is deformed to match rCBF SPECT volume. This process allows automatic characterisation of rCBF variation into vascular cerebral territories. In order to validate this technique, we examined the rCBF values of 26 patients with various cerebrovascular diseases. The results obtained from this experimentation showed that this technique is suitable for automatic quantification and systematisation of CBF in clinical routine
Riou, Laurent. "Mecanismes de fixation cellulaire de tcn-noet, un nouveau traceur radioactif de la perfusion myocardique". Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10111.
Texto completoFerré, Jean-Christophe. "Evaluation et optimisation de lʹacquisition et du post-traitement de lʹétude de la perfusion cérébrale par ʺ Arterial Spin Labeling ʺ". Rennes 1, 2011. http://www.theses.fr/2011REN1B149.
Texto completoArterial spin labeling (ASL) is a magnetic resonance perfusion imaging technique for measuring cerebral blood flow (CBF) which uses magnetically labeled arterial blood water as an endogenous tracer. ASL is completely noninvasive and can be repeated because it is performed without injection of contrast media, or radiation exposure. Moreover, CBF quantification is convenient and reproducible. However ASL is a low signal-to-noise ratio measurement technique. This technique becomes available on clinical MRI scanner. In this context, the aim of this work was to assess and optimize the image acquisition and the data processing acquired with two clinical techniques. We have demonstrated a correlation between acquisition parameters and hemodynamic parameters and we showed a maps’ quality improving using 32-channel coil combined with parallel imaging. New denoising methods were implemented and an optimized complete workflow was used to compare fASL and BOLD fMRI. A “template” approach was also assessed to detect individual increased perfusion area. Clinically, we used ASL to detect hypoperfusion defect on acute ischemic stroke and focal perfusion abnormalities in patients with chronic and resistant depression. Our results showed that a combination of optimized conditions acquisition and dedicated processing could help ASL to be more accurate in clinical research and practice
Roeloffs, Volkert Brar Verfasser], Jens [Akademischer Betreuer] [Gutachter] [Frahm, Marina [Gutachter] Bennati y Michael [Gutachter] Bock. "Development of Advanced Acquisition and Reconstruction Techniques for Real-Time Perfusion MRI / Volkert Brar Roeloffs ; Gutachter: Jens Frahm, Marina Bennati, Michael Bock ; Betreuer: Jens Frahm". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://d-nb.info/1123282986/34.
Texto completoPoujol, Julie. "Techniques d'acquisitions et reconstructions IRM rapides pour améliorer la détection du cancer du sein". Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0143/document.
Texto completoBreast cancer is nowadays the first cause of female cancer and the first cause of female death by cancer. Breast MRI is only performed in second intention when other imaging modalities cannot lead to a confident diagnosis. In high risk women population, breast MRI is recommended as an annual screening tool because of its higher sensitivity to detect breast cancer. Breast MRI needs contrast agent injection to visualize enhancing lesions and the diagnosis is mostly based on morphological analysis of these lesions. Therefore, an acquisition with high spatial resolution is needed. Despite the use of conventional MRI acceleration techniques, the volume of data to be acquired remains quite large and the temporal resolution of the exam is around one minute. This low temporal resolution may be the cause of the low specificity of breast MRI exam. Breast MRI with higher temporal resolution will allow the use of pharmacokinetic models to access physiological parameters and lesion specifications. The main aim of this work is to develop a MRI sequence allowing a flexible use of the acquired data at the reconstruction stage. On the one hand, the images can be reconstructed with a conventional reconstruction like the protocol used in clinical routine. On the other hand, the new MRI sequence will also allow the reconstruction of images with a higher temporal resolution allowing the use of pharmacokinetic models. The development of this sequence was done by modifying the acquisition order in the Fourier domain. A random acquisition of the Fourier domain will allow the reconstruction of sub-sampled domains acquired faster. We paid attention to fat suppression efficiency with this new Fourier domain acquisition order. Tests were performed on phantom, female volunteers and patients. These tests showed that the random acquisition did not impact the quality of images (MRI signal and lesion morphology) obtained by conventional reconstruction thus allowing the conventional diagnosis. The reconstructions of the sub-sampled Fourier domains were made using Compressed Sensing reconstructions to remove sub-sampling artifacts. These reconstructions were developed and tested on digital phantoms reproducing breast MRI. The potential of this new MRI acquisition was tested on an artificial enhancing breast lesion developed especially for this purpose
Adams, William P. "Thyroid Hormone as a Method of Reducing Damage to Donor Hearts after Circulatory Arrest". VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4766.
Texto completoHe, Rui. "Évaluation d'une analyse voxel à voxel dans l'accident vasculaire cérébral à partir d'images IRM multiparamétriques". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAS026/document.
Texto completoStroke is the leading cause of disability in adults. Beyond the narrow time window and possible risks of thrombolysis and mechanical thrombectomy, cell-therapies have strong potential. Reports showed that transplanted stem cells can enhance functional recovery after ischemic stroke in rodent models.To assess the mechanisms underlying the cell-therapy benefit after stroke, imaging is necessary. Multiparametric magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI), has become the gold standard to evaluate stroke characteristics. MRI also plays an important role in the monitoring of cerebral tissue following stroke from the acute to the chronic phase. However, the spatial heterogeneity of each stroke lesion and its dynamic reorganization over time, which may be related to the effect of a therapy, remain a challenge for traditional image analysis techniques. To evaluate the effect of new therapeutic strategies, spatial and temporal lesion heterogeneities need to be more accurately characterized and quantified.The current image analysis techniques, based on mean values obtained from regions of interest (ROIs), hide the intralesional heterogeneity. Histogram-based techniques provide an evaluation of lesion heterogeneity but fail to yield spatial information. The parametric response map (PRM) is an alternative, voxel-based analysis technique, which has been established in oncology as a promising tool to better investigate parametric changes over time at the voxel level which concern the therapeutic response or prognosis of disease.The PhD project was divided into two parts: a preclinical and a clinical study. The goal of the first study was to evaluate the PRM analysis using MRI data collected after the intravenous injection of human mesenchymal stem cells (hMSCs) in an experimental stroke model. The apparent diffusion coefficient (ADC), cerebral blood volume (CBV) and vessel size index (VSI) were mapped using 7T MRI. Two analytic procedures, the standard whole-lesion approach and the PRM, were performed on data collected at 4 time points in transient middle cerebral artery occlusion (MCAo) models treated with either hMSC or vehicle and in sham animals. During the second PhD project, 6 MR parametric maps (diffusion and perfusion maps) were collected in 30 stroke patients (the ISIS / HERMES clinical trial). MRI data, analyzed with both a classic mean value and a PRM approaches, were correlated with the evaluation of functional recovery after stroke measured with the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Scale (mRS) at 4 time points.In both studies, PRM analysis of MR parametric maps reveals fine changes of the lesion induced by a cell therapy (preclincal study) and correlate with long-term prognosis (clinical study).In conclusion, the PRM analysis could be used as an imaging biomarker of therapeutic efficacy and of prognostic biomarker of stroke patients
Mouton, Olivier. "Étude du comportement biologique de bis (N-ethoxy, N-ethyldithiocarbamato) nitruro 99mTc(V), 99mTcN-NOET, un nouveau marqueur de la perfusion myocardique". Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10296.
Texto completoPagès, Pierre-Benoît. "Technique de perfusion pulmonaire isolée de chimiothérapie chez le porc". Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOMU01/document.
Texto completoIntroduction: The isolated lung perfusion (ILP) is an experimental technique which main objective is to deliver high dose of cytotoxic agent to the lung tissue without systemic exposure. The thesis took place in three stages: first stage, setting in vitro the chemotherapy the most efficient against colorectal cancer (CCR) cells in 30 min. Second stage, develop the ILP technique in a pig model. Third stage, lead a dose escalation study with chemotherapy by ILP.Methods: First stage, efficacy of various cytotoxic molecules against a panel of human CCR cell lines was tested in vitro after a 30-minute exposure. Second stage, pigs were treated with chemotherapy delivered by ILP during 30 minutes and kept alive during a month. Third stage, chemotherapy doses were increase in order to obtain acute toxicity or death of animals.Results: Gemcitabine (GEM) was the most efficient drug against CCR cells in 30 minutes. ILP with GEM permit to maintain high concentration in the lung parenchyma and pigs survival during one month. No systemic leaks were detected. Dose increase of GEM conduct to determine the maximal tolerated dose of GEM by ILP to 320 mg. Conclusions: ILP with GEM is a safety and reproducible technique allowing high GEM concentrations in the lung tissue
Ibarrola, Danielle. "Application des techniques d'imagerie par résonance magnétique nucléaire à l'étude préclinique de l'ischémie cérébrale focale : action d'un agent de contraste superparamagnétique et essai pharmacologique de l'effet d'un antagoniste du récepteur NMDA chez le rat in vivo". Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE19003.
Texto completoLe, Gac de Lansalut Christina. "Chambres implantables pour perfusions intra-veineuses : bilan d'une expérience de 170 observations". Bordeaux 2, 1989. http://www.theses.fr/1989BOR25061.
Texto completoVerclytte, Sébastien. "Optimisation et évaluation de la perfusion cérébrale par technique de marquage de spin dans la Maladie d'Alzheimer à début précoce". Thesis, Lille 2, 2015. http://www.theses.fr/2015LIL2S029/document.
Texto completoThe diagnosis of Alzheimer's disease (AD) in patients under the age of 65 years, called early-onset Alzheimer's disease (EOAD), remains a challenging issue due to the high incidence of atypical clinical presentations with non-memory symptoms. Although EAOD has been widely explored by structural and functional imaging, no previous study has examined the contribution of ASL in the assessment of cortical perfusion in this disease. Indeed, the analysis of ASL remains complex, especially at the individual level, due to the weak signal-to-noise ratio of the perfusion maps and the heterogeneity of pathological areas in the initial phase of the disease. Our first objective was technical and has consisted in optimizing the visual interpretation of ASL maps by the cortical surface-based projection of the perfusion alterations on the structural T1 sequence acquired during the same imaging protocol, providing a 3D interactive display of the perfusion data. Data processing included several successive steps, such as a partial volume effect correction, a specific intensity normalization and a surface-based smoothing process. It was applied on the perfusion maps of eighteen EOAD patients and the quality of segmentation and of cortical surface-based perfusion maps were scored as optimal in 72% in both cases by two readers. Our second objective was clinical and aimed to characterize the cerebral hypoperfusion and hypometabolism by ASL and 18F-FDG-PET in a group of 37 EOAD patients. Our preliminary study showed: (i) a similar pathological pattern located in the inferior parietal lobules and in the temporal cortex, (ii) discrepancies between the two modalities with the presence of more widespread hypometabolic regions detected by 18F-FDGPET and additionnai areas of alterations in the frontal lobes detected by ASL without apparent hypometabolism. Our studies suggest that ASL may become a useful complementary tool which, in combination with the existing structural and functional techniques, could offer improved efficiency in the difficult early detection of EOAD and AD. Its use in clinical practice, however, requires an optimization of its visual representation, and the cortical surface-based projection applied in this work represents one of the potential ways to this image quality improvement
GIKUNDA, MILLICENT NKIROTE. "An improved sample loading technique for cellular metabolic response monitoring under pressure". Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1470194454.
Texto completoStrang, Christof. "The Effect of CO2-Pneumoperitoneum on Ventilation Perfusion Distribution of the Lung". Doctoral thesis, Uppsala universitet, Klinisk fysiologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-149746.
Texto completoDuncan, Henry J. "An isotope washout technique to study skin perfusion pressure and vascular resistance in diabetes, hypertension and peripheral vascular disease /". Cover title, title page, table of contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09MD/09mdd911.pdf.
Texto completoBen, Mahmoud Sinan Marie Pierre-Yves. "Tomoscintigraphie de perfusion cérébrale dans l'épilepsie lobaire temporale pharmacorésistante comparaison des différentes méthodes d'analyse /". [S.l.] : [s.n.], 2007. http://www.scd.uhp-nancy.fr/docnum/SCDMED_T_2007_BEN_MAHMOUD_SINAN.pdf.
Texto completoStupar, Vasile. "Polarisation d'hélium3 par la technique d'échange de spin et applications en IRM de la ventilation et de la perfusion pulmonaire". Lyon 1, 2004. http://www.theses.fr/2004LYO10105.
Texto completoZaccariotto, Eva. "The blood-brain barrier and San Filippo Syndrome: a model for pathophisiology studies of CNS in lysosomal storage diseases". Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426008.
Texto completoLe patologie d’accumulo lisosomiale (LSD) rappresentano un grosso ed eterogeneo gruppo di malattie genetiche che derivano da difetti in diversi aspetti della biologia lisosomiale. Queste patologie interessano più comunemente i bambini, e per la maggior parte determinano coinvolgimento neurologico che, quando presente, non è trattabile. Tutti gli animali con un sistema nervoso centrale (SNC) ben sviluppato hanno una barriera emato-encefalica (BEE) che isola ampiamente il cervello dalle alterazioni nella composizione del flusso del sangue e dai continui cambiamenti che avvengono in generale in questi fluidi corporei. Questa barriera impedisce anche la somministrazione globale al SNC di molte sostanze terapeutiche. Diversi studi condotti in modelli murini delle malattie d’accumulo lisosomiale, come le patologie di Batten, Sandhoff e GM1 gangliosidosi, hanno inoltre suggerito che la BEE possa essere danneggiata come parte integrante del processo patologico. Lo scopo del presente progetto è stato quello di determinare se avvenissero simili cambiamenti nella BEE nella sindrome di Sanfilippo. La tecnica della perfusione cerebrale in situ è il sistema di elezione per questo studio in quanto per le molecole analizzate non è necessario considerare gli effetti dovuti ad eventuali legami con le proteine plasmatiche, metabolismo e altre interazioni all’interno del corpo. Inoltre, offre una sensibilità superiore rispetto ad altri metodi basati su tracciante e può essere usata per quantificare precisamente il trasporto di soluti attraverso la BEE. Abbiamo apportato una nuova modifica alla tecnica originale di Takasato e Smith (1984) che assicura che tutte le regioni del cervello del topo siano perfuse piuttosto che solo la zona di una singola carotide. Questo è importante poiché nelle LSD tutte le regioni cerebrali sono coinvolte e il circulus arteriosus cerebri presenta differenti gradi di completezza in diversi ceppi murini (Ward et al. 1990). Quindi il metodo permette che la funzione della BEE sia valutata in tutte le regioni, e può essere applicato per comparare animali modificati geneticamente di diversi background genetici. Diversi parametri, come il flusso della perfusione cerebrale, il volume vascolare del cervello, e il trasporto carrier-mediato degli amminoacidi acido glutammico e glicina, sono stati investigati per determinare se il metodo della perfusione cerebrale in situ possa essere applicato al topo senza disturbare l’integrità fisica e funzionale della BEE. Sono stati anche condotti studi con nitrato di lantano, e analizzati al microscopio elettronico, per valutare se le giunzioni occludenti subissero aperture durante il corso della perfusione. Una volta che la tecnica della perfusione cerebrale in situ è stata provata come strumento reale per la valutazione della penetrazione di traccianti attraverso la BEE, questo metodo è stato applicato per determinare se ci fossero cambiamenti nella BEE in modelli murini di due forme della sindrome di Sanfilippo (MPS IIIA e MPS IIIB) in confronto ai loro rispettivi ceppi murini di controllo. [14C]-saccarosio e [3H]-inulina sono stati impiegati per valutare il volume vascolare, ma normalmente non penetrano la membrana, a meno che non sia difettiva. [14C]-diazepam è stato utilizzato come marker del flusso sanguigno cerebrale; e [3H]-glicina, [3H]-acido glutammico e [3H]-tirosina come sostanze carrier-mediate a bassa penetrazione cerebrale. Questi sono amminoacidi neuro-eccitatori che possono causare danni al cervello se la loro entrata nel cervello è aumentata. Dati iniziali per la sindrome di Sanfilippo dalla tecnica della perfusione cerebrale in situ, sebbene necessitino di essere confermati e approfonditi, hanno dimostrato la tipica eterogeneità clinica dei pazienti di Sanfilippo ed evidenziano chiaramente che avvengono alcuni cambiamenti nella BEE. Anche la permeabilità di [3H]-N-butil-deossinojirimicina (NB-DNJ, miglustat, Zavesca®) alla BEE è stato valutata poichè è attualmente impiegata nella terapia di riduzione del substrato (SRT), si ritiene che penetri la BEE e teoricamente potrebbe essere usata per trattare l’accumulo secondario nella sindrome di Sanfilippo. Da iniezioni intraperitoneali di [3H]- NB-DNJ e valutazione della costante d’influsso unidirezionale Kin per intervalli di tempo fino a 60 minuti, un lento ma progressivo assorbimento di questa piccola molecola è stato dimostrato. Una comprensione maggiore della BEE e della sua funzione, sia in salute sia in malattia, è assolutamente e criticamente necessaria per lo sviluppo di farmaci nuovi e migliori che possano riparare la BEE e in più siano anche in grado di attraversare la BEE allo scopo di trattare manifestazioni precoci della sindrome di Sanfilippo nel SNC. Questi studi produrranno informazioni che aiuteranno la somministrazione di farmaci al SNC in generale e aumenteranno ulteriormente la possibilità di trattare un ampio numero di patologie neurodegenerative.
Werndle, Melissa Cheng-Hwa. "Development of a novel technique to measure and characterise spinal cord perfusion pressure in patients with acute traumatic spinal cord injury". Thesis, St George's, University of London, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675934.
Texto completoWatanabe, Yuji, Gerhard P. Püschel, Andreas Gardemann y Kurt Jungermann. "Presinusoidal and proximal intrasinusoidal confluence of hepatic artery and portal vein in rat liver : functional evidence by orthograde and retrograde bivascular perfusion". Universität Potsdam, 1994. http://opus.kobv.de/ubp/volltexte/2008/1670/.
Texto completoDesmoulin, Franck. "La Spectroscopie de résonance magnétique nucléaire : une nouvelle technique d'investigation du métabolisme hépatique. Application à l'étude du métabolisme énergétique et intermédiaire sur le Foie. Métabolisme. Résonance magnétique de rat excisé perfusé". Aix-Marseille 1, 1986. http://www.theses.fr/1986AIX11040.
Texto completoPádua, Rodrigo Donizete Santana de. "Corregistro de imagens aplicado à construção de modelos de normalidade de SPECT cardíaco e detecção de defeitos de perfusão miocárdica". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/82/82131/tde-02052012-154125/.
Texto completoThe computer-aided medical imaging analysis allows the quantitative analysis of abnormalities and enhances diagnostic accuracy. This type of analysis is important for nuclear medicine that uses Single Photon Emission Computed Tomography (SPECT), because in the group of three-dimensional data images, subtle patterns of abnormalities often are important clinical findings. However, images can suffer interference from attenuation artifacts of the emission of photons by soft parts of the body, which reduces their diagnostic accuracy. Since there are attenuation parameters computed in a template that allows for comparison with images of a given patient, the artifacts interference can be corrected with a gain in diagnostic accuracy, without the need of using correction techniques that increase the radiation exposure dose of the patient. The purpose of this study was to create an atlas of myocardial perfusion scintigraphy, which was obtained from images of normal individuals and the development of a computational algorithm for detection of myocardial perfusion abnormalities by statistical comparison of atlas templates with images of patients. Methods of image registration of same modality and other image processing techniques were studied and used for comparison of patient images with the appropriate template. By the visual analysis of the templates it was found its validity as a representative image of normal perfusion. For the detection evaluation, the situation of myocardial segments (normal or abnormal) indicated by the detection algorithm was compared with the situation indicated in the medical appraisal report obtained by agreement of two specialists in order to determine the agreement and disagreement of the technique regarding the medical appraisal report and obtaining the statistical significance. Thus, there was a positive agreement index of the technique regarding the medical appraisal report of approximately 50%, a negative agreement index close to 82% and a general agreement index near 68%. The Fisher exact test was applied to the contingency tables, yielding a two-sided p-value less than 0.0001, that indicates a very low probability of the agreements have been obtained by chance. Algorithm improvements should be implemented and further tests with an effective gold-standard will be conducted to validate the technique.
Favre, de Thierrens Carle. "Contribution à l'étude de l'incidence des molécules-signaux du système neuro-endocrinien dans la physiopathologie odontologique : apport de la technique de "perfusion push-pull modifiée" à l'étude in vivo des prostaglandines et des enképhalines pulpaires ; détection et quantification radioimmunologique de somatostatine-IR dans la pulpe dentaire du rat". Montpellier 1, 1996. http://www.theses.fr/1996MON12200.
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