Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 39 for “"magnetic resonance spectroscopy (MRS)"”.
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Comparison of Magnetic Resonance Spectroscopy (MRS) data in children with and without HIV at 11-12 years
… investigated at a chemical level through proton magnetic resonance spectroscopy (1H-MRS). Previous studies in children have largely focused on individual metabolite changes. However, several adult studies have now advanced beyond this to address patterns of metabolic activity that are altered …
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Real-time motion and main magnetic field correction in MR spectroscopy using an EPI volumetric navigator
… groups where subjects do not lie still during Magnetic Resonance Spectroscopy (MRS) scans, real-time volume of interest (VOI), frequency, and main magnetic field (B0) shim correction may be necessary. This work demonstrates firstly that head movement causes significant B0 disruption in both …
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The role of inflammation, oxidative stress and the apolipoprotein E genotype in HIV-associated cognitive impairment: a clinical, biochemical and neuro-imaging study
… stress, inflammatory changes in the brain on magnetic resonance spectroscopy (MRS) and the role of the APOE E4 allele in HIV-associated dementia (HAD) in a South African population. We hypothesized that cognitive impairment and brain inflammation would correlate with systemic markers of …
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Applications of SLIM (Spectral Localization by Imaging) localization technique
… of living systems, applications of nuclear magnetic resonance spectroscopy (MRS) to the biological system require techniques that can discriminate signals according to their spatial origins and detect signals only from the operator-designated regions. These techniques are called localization …
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Investigating brain metabolite levels in adolescents living with HIV using atlas-based magnetic resonance spectroscopic imaging (MRSI)
… studies are predominantly based on single voxel magnetic resonance spectroscopy (MRS) in younger children, with inconsistent findings. We aimed to develop atlas-based pipelines for analysing MRSI data to examine whether there are differences in brain metabolite levels between adolescents with …
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MR Spectroscopy and SWI: Neuropsyehological Outcome after Pediatric Brain Injury
… the efficacies of acute single and multi-voxel Magnetic Resonance Spectroscopy (MRS) and Susceptibility Weighted Imaging (SWI) when predicting long-term neurocognitive functioning in pediatric TBI patients. Twenty children/adolescents (mean age 13.3 years, 5.8 SD) treated at Loma Linda …
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Magnetic resonance spectroscopy: techniques and applications in thermometry and metabolite mapping
Magnetic Resonance Spectroscopy (MRS) is a useful tool for obtaining information about metabolite concentrations. Information that can be extrapolated from these concentrations may be absolute or relative in nature, depending on the availability of an internal reference. For example, MR Thermometry …
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Tissue oxymetry using magnetic resonance spectroscopy
… By using paramagnetism of molecular oxygen, magnetic resonance spectroscopy (MRS) can be used to measure tissue oxygenation. Chemical shifts of brain metabolites and water have a downfield shift with increased amounts of oxygen. Chemical shifts were linearly dependent on the fraction of …
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Short echo time single voxel magnetic resonance spectoscopy in the characterisation of childhood brain tumours.
… the most common solid tumour in childhood, while Magnetic Resonance Spectroscopy (MRS) studies have been performed on brain tumours previously, the majority have been performed on the adult patient population and at long echo times. The work presented in this thesis outlines work performed in the …
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Longitudinal analysis of Brain Metabolite levels for HIV infected Children from ages five to eleven
… from 5-11 years in three brain regions using Magnetic Resonance Spectroscopy (MRS). We used univariate linear mixed effect models to identify independent profiles of the metabolites measured in each region of the brain. To explore the metabolite trends in a multivariate setting we generated …
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Biomarkers of cell stress and cell death detected by proton high resolution magic angle spinning (\(^1\)H HR-MAS) nuclear magnetic resonance (NMR) spectroscopy in a rat glioma cell line
… response improves clinical management, in vivo. Magnetic resonance spectroscopy (MRS) has demonstrated potential for identifying early biomarkers of effective treatment. However, more detailed in vitro studies are required to improve our understanding and facilitate its use. The aim of this study …
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Development and analysis of hierarchical feedforward neural network systems for classification of motor neurone disease based on magnetic resonance spectra
… are associated with Motor Neurone Disease (MND). Magnetic Resonance Spectroscopy (MRS) has been performed on the brains of MND patients and control volunteers to acquire signals which contain information about brain metabolites from within the motor cortex area. Discrimination between JvThD and …
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Functional Magnetic Resonance Spectroscopy in First-Episode Schizophrenia: Measuring Glutamate and Glutathione Dynamics at 7-Tesla
… and manifestation of schizophrenia symptoms. Magnetic resonance spectroscopy (MRS) provides a non-invasive means to observe in-vivo brain chemistry, including glutamate and glutathione. By adding a functional component to an MRS paradigm (fMRS), such as the color-word Stroop task, it is …
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Sensors and System Integration for Magnetic Resonance Image (MRI)-Guided and Robot-Assisted Interventions
Demand for magnetic resonance image (MRI)-guided interventions and robot-assisted surgeries continues to increase in the field of medical robotics. MRI-guided interventions provide pre-/intra-operative MR images and intraoperative manipulations. Robot-assisted surgeries guarantee higher safety and …
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Understanding and ameliorating perturbations of human cerebral energy metabolism after major trauma
… 13C labelled high-resolution nuclear magnetic resonance (NMR) and in-vivo 31P magnetic resonance spectroscopy (MRS) I have furthered our understanding of perturbations in human brain energy metabolism in the acute phase of a major traumatic brain injury. Furthermore, I have explored …
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Model-based reconstruction of magnetic resonance spectroscopic imaging
Magnetic resonance imaging (MRI) is a medical imaging technique that is used to obtain images of soft tissue throughout the body. Since its development in the 1970s, MRI has gained tremendous importance in clinical practice because it can produce high quality images of diagnostic value in an ever …
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Investigating The Metabolic Progression of Glioblastoma With Hyperpolarized Magnetic Resonance
… whether metabolic imaging with hyperpolarized magnetic resonance spectroscopy (MRS) could detect changes in tumor progression more rapidly than conventional anatomic magnetic resonance imaging (MRI) in patient-derived GBM murine models. To comprehensively capture the dynamic nature of cancer …
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Inhibitory mechanisms for visual learning in the human brain
… show that BOLD signals as measured by functional Magnetic Resonance Imaging (fMRI) do not differentiate between the two proposed mechanisms. In contrast, Magnetic Resonance Spectroscopy (MRS) provides strong evidence for the distinct involvement of GABAergic inhibition in visual plasticity. …
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Magnetic Resonance Spectroscopy Imaging of 2-Hydroxyglutarate in Brain Tumors at 3T and 7T In Vivo
… identification of 2-hydroxyglutarate (2HG) by 1H magnetic resonance spectroscopy (MRS) in patients with isocitrate dehydrogenase mutant gliomas is a significant breakthrough in neuro-oncology imaging. 2HG is the first imaging biomarker that is specific to a genetic mutation in gliomas, making the …
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Noninvasive Monitoring of CCl4 Induced Acute and Chronic Liver Damage in Rat by Single Quantum and Triple Quantum Filtered 23Na Magnetic Resonance Imaging
… (SQ) and triple quantum filtered (TQF) 23Na magnetic resonance imaging (MRI) was used to monitor the severity and progression of CCl4 induced acute and chronic liver damage in rat model. SQ 23Na MRI was proposed to measure the 23Na signal intensity (SI) of total tissue sodium ions, and TQF …
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