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285 full-text articles. Page 1 of 13.

Behavior Coding Strategies: Population Coupling And The Functional Role Of Excitatory/Inhibitory Balance In Primary Motor Cortex, Patrick Aaron Kells 2018 University of Arkansas, Fayetteville

Behavior Coding Strategies: Population Coupling And The Functional Role Of Excitatory/Inhibitory Balance In Primary Motor Cortex, Patrick Aaron Kells

Theses and Dissertations

The complexities of an organism’s experience of- and interaction with the world are emergent phenomena produced by large populations of neurons within the cerebral cortex and other brain regions. The network dynamics of these populations have been shown to be sometimes synchronous, with many neurons firing together, and sometimes asynchronous, with neurons firing more independently, leading to a decades-old debate within the neuroscience community. This discrepancy comes from viewing the system at two different scales; at the single cell level, the spiking activity of two neurons within cortex tend to be rather independent, but when the average activity of ...


Design And Development Of A Phantom For Tomosynthesis With Potential For Automated Analysis Via The Cloud., David Goodenough, Josh Levy, Hildur Olafsdottir, Ingvi Olafsson 2018 George Washington University

Design And Development Of A Phantom For Tomosynthesis With Potential For Automated Analysis Via The Cloud., David Goodenough, Josh Levy, Hildur Olafsdottir, Ingvi Olafsson

Radiology Faculty Publications

This paper describes Development of a Phantom for Tomosynthesis with Potential for Automated Analysis via the Cloud. Several studies are underway to investigate the effectiveness of Tomosynthesis Mammographic Image Screening, including the large TMIST project as funded by the National Cancer Institute https://www.cancer.gov/about-cancer/treatment/clinical-trials/nci-supported/tmist. The development of the phantom described in this paper follows initiatives from the FDA, the AAPM TG245 task group, and European Reference Organization (EUREF) for Quality Assured Breast Screening and Diagnostic Services Committee report noting, that no formal endorsement nor recommendation for use has been sought, or granted by ...


Imaging Biomarkers Of Pulmonary Structure And Function, Dante Capaldi 2018 The University of Western Ontario

Imaging Biomarkers Of Pulmonary Structure And Function, Dante Capaldi

Electronic Thesis and Dissertation Repository

Asthma and chronic obstructive pulmonary disease (COPD) are characterized by airflow limitations resulting from airway obstruction and/or tissue destruction. The diagnosis and monitoring of these pulmonary diseases is primarily performed using spirometry, specifically the forced expiratory volume in one second (FEV1), which measures global airflow obstruction and provides no regional information of the different underlying disease pathologies. The limitations of spirometry and current therapies for lung disease patients have motivated the development of pulmonary imaging approaches, such as computed tomography (CT) and magnetic resonance imaging (MRI). Inhaled hyperpolarized noble gas MRI, specifically using helium-3 (3He) and xenon-129 ...


High Performance Optical Computed Tomography For Accurate Three-Dimensional Radiation Dosimetry, Kurtis Hendrik Dekker 2018 The University of Western Ontario

High Performance Optical Computed Tomography For Accurate Three-Dimensional Radiation Dosimetry, Kurtis Hendrik Dekker

Electronic Thesis and Dissertation Repository

Optical computed tomography (CT) imaging of radiochromic gel dosimeters is a method for truly three-dimensional radiation dosimetry. Although optical CT dosimetry is not widely used currently due to previous concerns with speed and accuracy, the complexity of modern radiotherapy is increasing the need for a true 3D dosimeter. This thesis reports technical improvements that bring the performance of optical CT to a clinically useful level. New scanner designs and improved scanning and reconstruction techniques are described.

First, we designed and implemented a new light source for a cone-beam optical CT system which reduced the scatter to primary contribution in CT ...


Analysis Of Subchondral Bone And Microvessels Using A Novel Vascular Perfusion Contrast Agent And Optimized Dual-Energy Computed Tomography, Justin J. Tse 2018 The University of Western Ontario

Analysis Of Subchondral Bone And Microvessels Using A Novel Vascular Perfusion Contrast Agent And Optimized Dual-Energy Computed Tomography, Justin J. Tse

Electronic Thesis and Dissertation Repository

Osteoarthritis (OA), is a chronic debilitating disease that affects millions of individuals and is characterized by the degeneration of joint subchondral bone and cartilage. These tissue degenerations manifest as joint pain, limited range of joint motion, and overall diminished quality of life. Currently, the exact mechanism(s) and cause(s) by which OA initiates and progresses remain unknown. The multi-factorial complex nature of OA (i.e. age, diabetes, obesity, and prior injuries have all been shown to play a role in OA) contributes to the current lack of a cure or effective long-term treatment for OA.

One re-emerging and interesting ...


Optimization Of Design Procedures For Delta Relaxation Enhanced Magnetic Resonance, Daniel J. Martire 2018 The University of Western Ontario

Optimization Of Design Procedures For Delta Relaxation Enhanced Magnetic Resonance, Daniel J. Martire

Electronic Thesis and Dissertation Repository

Delta relaxation enhanced magnetic resonance (dreMR) is a magnetic resonance imaging (MRI) method that produces contrast based on longitudinal relaxation dispersion. Through modulation of the magnetic field using an actively-shielded, field-cycling insert coil, this technique increases probe specificity and suppresses remaining signal. However, significant improvements are needed. This thesis addresses two advancements in dreMR with a focus on optimizing design procedures. A general procedure was developed to design split power solenoid magnets. The procedure was then applied to the design of a switched-field exposure system. A coil was constructed and the method was validated. This procedure can be used for ...


Advances In Dual-Energy Computed Tomography Imaging Of Radiological Properties, Dong Han 2018 Virginia Commonwealth University

Advances In Dual-Energy Computed Tomography Imaging Of Radiological Properties, Dong Han

Theses and Dissertations

Dual-energy computed tomography (DECT) has shown great potential in the reduction of uncertainties of proton ranges and low energy photon cross section estimation used in radiation therapy planning. The work presented herein investigated three contributions for advancing DECT applications. 1) A linear and separable two-parameter DECT, the basis vector model (BVM) was used to estimate proton stopping power. Compared to other nonlinear two-parameter models in the literature, the BVM model shows a comparable accuracy achieved for typical human tissues. This model outperforms other nonlinear models in estimations of linear attenuation coefficients. This is the first study to clearly illustrate the ...


Hepcidin-Mediated Iron Regulation In P19 Cells Is Detectable By Mri, Kobra Alizadeh Pourbouyeh 2017 The University of Western Ontario

Hepcidin-Mediated Iron Regulation In P19 Cells Is Detectable By Mri, Kobra Alizadeh Pourbouyeh

Electronic Thesis and Dissertation Repository

Magnetic resonance imaging (MRI) can be used to track cellular activities in the body using iron-based contrast agents. However, intrinsic cellular iron handling mechanisms may also influence the detection of magnetic resonance (MR) contrast. For instance, inflammation involves downregulation of iron export in macrophages by the hormone hepcidin, due to degradation of the iron export protein, ferroportin (Fpn). We examined the effect of hepcidin on iron regulation and MR transverse relaxation rates in multi-potent P19 cells, which display high iron export activity, similar to macrophages. In response to varying conditions of iron supplementation, our results showed similar Fpn expression in ...


Evaluating Small Airways Disease In Asthma And Copd Using The Forced Oscillation Technique And Magnetic Resonance Imaging, Heather M. Young 2017 The University of Western Ontario

Evaluating Small Airways Disease In Asthma And Copd Using The Forced Oscillation Technique And Magnetic Resonance Imaging, Heather M. Young

Electronic Thesis and Dissertation Repository

Obstructive lung disease, including asthma and chronic obstructive pulmonary disease (COPD), is characterized by heterogeneous ventilation. Unfortunately, the underlying structure-function relationships and the relationships between measurements of heterogeneity and patient quality-of-life in obstructive lung disease are not well understood. Hyperpolarized noble gas MRI is used to visualize and quantify ventilation distribution and the forced oscillation technique (FOT) applies a multi-frequency pressure oscillation at the mouth to measure respiratory impedance to airflow (including resistance and reactance). My objective was to use FOT, ventilation MRI and computational airway tree modeling to better understand ventilation heterogeneity in asthma and COPD. FOT-measured respiratory system ...


A Longitudinal Study Of Tumour Metabolism Using Hyperpolarized Carbon-13 Magnetic Resonance Spectroscopic Imaging In A Preclinical Model Of Glioma, Heeseung Lim 2017 The University of Western Ontario

A Longitudinal Study Of Tumour Metabolism Using Hyperpolarized Carbon-13 Magnetic Resonance Spectroscopic Imaging In A Preclinical Model Of Glioma, Heeseung Lim

Electronic Thesis and Dissertation Repository

Glioma is the most common and aggressive primary malignant brain tumour. Glioma is typically treated with surgery followed by radio/chemotherapy. Even with aggressive treatment, median survival time is expected to be ~12 to 15 months. Reoccurrence of glioma is almost inevitable, further threatening the well-being of patients who have already endured rigorous treatment. Therefore, it is paramount to choose the most effective therapy and to accurately determine outcome as early as possible to provide optimum end-of-life care. Tumours alter their metabolism in response to increasing energy demands, mainly through increased glycolysis and accompanying lactate production. This increases production of ...


Characterization Of An Orthotopic Rat Model Of Glioblastoma Using Multiparametric Magnetic Resonance Imaging And Bioluminescence Imaging, Trung Le 2017 The University of Western Ontario

Characterization Of An Orthotopic Rat Model Of Glioblastoma Using Multiparametric Magnetic Resonance Imaging And Bioluminescence Imaging, Trung Le

Electronic Thesis and Dissertation Repository

Glioblastoma multiforme (GBM) is a lethal and incurable disease. The C6 rat model of GBM shares several similarities to human GBM and longitudinal non-invasive imaging may allow tumour features to be studied. In this thesis, a multimodality imaging framework, consisting of bioluminescence imaging (BLI) and multiparametric magnetic resonance imaging (mpMRI), was applied to the C6 rat model to characterize the growth of orthotopic tumours. BLI signal, a measure of cell viability, tended to increase and then decrease in the majority of animals, whereas tumour volume (from MRI) continually increased. Cellular viability and tumour volume did not correlate across all days ...


Saturation And Response Dependence Of Oslds And Microstar Reader In The High Dose Range For Intrabeam Kv X-Rays And Initial Investigation Into The Use Of Gafchromic Film As An In Vivo Dosimeter In The High Dose Region, Travis Bryant 2017 Oregon Health & Science University

Saturation And Response Dependence Of Oslds And Microstar Reader In The High Dose Range For Intrabeam Kv X-Rays And Initial Investigation Into The Use Of Gafchromic Film As An In Vivo Dosimeter In The High Dose Region, Travis Bryant

Scholar Archive

No abstract provided.


Skeletal Muscle Fibrosis In The Mdx/Utrn+/- Mouse Validates Its Suitability As A Murine Model Of Duchenne Muscular Dystrophy, Lisa M. Hoffman, William T. Hrinivich, Kelly M. Gutpell 2017 Western University

Skeletal Muscle Fibrosis In The Mdx/Utrn+/- Mouse Validates Its Suitability As A Murine Model Of Duchenne Muscular Dystrophy, Lisa M. Hoffman, William T. Hrinivich, Kelly M. Gutpell

Lisa Hoffman

Various therapeutic approaches have been studied for the treatment of Duchenne muscular dystrophy (DMD), but none of these approaches have led to significant long-term effects in patients. One reason for this observed inefficacy may be the use of inappropriate animal models for the testing of therapeutic agents. The mdx mouse is the most widely used murine model of DMD, yet it does not model the fibrotic progression observed in patients. Other murine models of DMD are available that lack one or both alleles of utrophin, a functional analog of dystrophin. The aim of this study was to compare fibrosis and ...


Characterization Of A Far-Red Analog Of Ghrelin For Imaging Ghs-R In P19-Derived Cardiomyocytes., Gregory A F Douglas, Rebecca McGirr, Carlie L Charlton, Dov B Kagan, Lisa M Hoffman, Leonard G Luyt, Savita Dhanvantari 2017 Selected Works

Characterization Of A Far-Red Analog Of Ghrelin For Imaging Ghs-R In P19-Derived Cardiomyocytes., Gregory A F Douglas, Rebecca Mcgirr, Carlie L Charlton, Dov B Kagan, Lisa M Hoffman, Leonard G Luyt, Savita Dhanvantari

Lisa Hoffman

Ghrelin and its receptor, the growth hormone secretagogue receptor (GHS-R), are expressed in the heart, and may function to promote cardiomyocyte survival, differentiation and contractility. Previously, we had generated a truncated analog of ghrelin conjugated to fluorescein isothiocyanate for the purposes of determining GHS-R expression in situ. We now report the generation and characterization of a far-red ghrelin analog, [Dpr(3)(octanoyl), Lys(19)(Cy5)]ghrelin (1-19), and show that it can be used to image changes in GHS-R in developing cardiomyocytes. We also generated the des-acyl analog, des-acyl [Lys(19)(Cy5)]ghrelin (1-19) and characterized its binding to mouse ...


Use Of Imaging Biomarkers To Assess Perfusion And Glucose Metabolism In The Skeletal Muscle Of Dystrophic Mice, Nabeel Ahmad, Ian Welch, Robert Grange, Jennifer Hadway, Savita Dhanvantari, David Hill, Ting-Yim Lee, Lisa M Hoffman 2017 The University of Western Ontario

Use Of Imaging Biomarkers To Assess Perfusion And Glucose Metabolism In The Skeletal Muscle Of Dystrophic Mice, Nabeel Ahmad, Ian Welch, Robert Grange, Jennifer Hadway, Savita Dhanvantari, David Hill, Ting-Yim Lee, Lisa M Hoffman

Lisa Hoffman

BACKGROUND: Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease that affects 1 in 3500 boys. The disease is characterized by progressive muscle degeneration that results from mutations in or loss of the cytoskeletal protein, dystrophin, from the glycoprotein membrane complex, thus increasing the susceptibility of contractile muscle to injury. To date, disease progression is typically assessed using invasive techniques such as muscle biopsies, and while there are recent reports of the use of magnetic resonance, ultrasound and optical imaging technologies to address the issue of disease progression and monitoring therapeutic intervention in dystrophic mice, our study aims to validate ...


Electrospun Collagen Nanofibers For Tissue Engineering, Nisha Sharma 2017 The University of Western Ontario

Electrospun Collagen Nanofibers For Tissue Engineering, Nisha Sharma

Electronic Thesis and Dissertation Repository

Design and fabrication of the scaffold is an important part of the tissue engineering process. Nanofibrous scaffolds based on proteins are gaining increasing acceptance due to its structural similarity to the extracellular matrix. Making use of the electrospinning technique, rat tail collagen type I nanofibers were produced using a collagen in hexafluoroisopropanol (HFIP) solution. In addition to optimizing the electrospinning process parameters, the effect of humidity on fiber morphology and diameter was investigated for fiber size control for particular tissue engineering applications. A generalized humidity effect on polymer fiber diameter of the polymer solution electrospinning process was developed. The as ...


Using Computed Tomography Perfusion To Evaluate The Blood-Brain-Barrier And Blood-Tumor-Barrier Response Following Focused Ultrasound Sonication With Microbubble Administration, Hassaan Ahmed 2017 The University of Western Ontario

Using Computed Tomography Perfusion To Evaluate The Blood-Brain-Barrier And Blood-Tumor-Barrier Response Following Focused Ultrasound Sonication With Microbubble Administration, Hassaan Ahmed

Electronic Thesis and Dissertation Repository

The blood-brain-barrier (BBB) is the single most limiting factor in the delivery of neurotherapeutics into the brain. Focused ultrasound sonication combined with intravenous microbubble administration (FUSwMB) is a novel technique that can transiently disrupt the BBB, with minimal vascular or tissue damage, allowing for localized drug delivery over the targeted region. The goals of this thesis are to: 1) use computed tomography (CT) perfusion to measure the permeability surface area product (PS) following USwMB in normal rabbits with an intact BBB, and 2) to evaluate the blood-tumor-barrier (BTB) PS response following FUSwMB in a C6 rat glioma model.


The Design, Fabrication, And Characterization Of Nanoparticle-Protein Interactions For Theranostic Applications, Wai Hei Tse 2017 The University of Western Ontario

The Design, Fabrication, And Characterization Of Nanoparticle-Protein Interactions For Theranostic Applications, Wai Hei Tse

Electronic Thesis and Dissertation Repository

Theranostics, a combination of therapeutics and diagnostics, spans a spectrum of research areas to provide new opportunities in developing new healthcare technologies and medicine at affordable prices. Through employing a personalized medicine approach, biotechnology can be tailored to the needs of an individual. Applications of theranostics include drug delivery carriers capable of sustained drug release and targeted delivery, biosensors with high sensitivity and selectivity, and diagnostic relevant entities that can be incorporated into the former technologies. Nanotechnology provides a suitable foundation for theranostics to build upon due to material-based properties; magnetism, biocompatibility, and quantum effects to name a few. Purpose ...


Volumetric, Magnetic Resonance-Visible, And Radiation-Sensitive Detectors For Magnetic Resonance Image-Guided Radiation Therapy, Hannah J. Lee 2017 The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences

Volumetric, Magnetic Resonance-Visible, And Radiation-Sensitive Detectors For Magnetic Resonance Image-Guided Radiation Therapy, Hannah J. Lee

UT GSBS Dissertations and Theses (Open Access)

VOLUMETRIC, MAGNETIC RESONANCE-VISIBLE, AND RADIATION-SENSITIVE DETECTORS FOR MAGNETIC RESONANCE IMAGE-GUIDED RADIATION THERAPY

Hannah Jungeun Lee

Advisory Professor: Geoffrey S. Ibbott, Ph.D.

Due to the superior soft-tissue contrast of magnetic resonance imaging (MRI) compared to conventional computed tomography (CT) and other on-board imaging techniques, several groups have integrated MRI and radiation treatment machine systems. The advent of MR image-guided radiation therapy (MR-IGRT) using systems, such as the 1.5 MRI – 7 MV linear accelerator (MR-Linac), now allow for improved soft-tissue on-board imaging for patient position and tumor target localization verification and the ability to assess functional biological tissue characteristics with ...


3d Ultrasound In The Management Of Post Hemorrhagic Ventricle Dilatation, Jessica Kishimoto 2017 The University of Western Ontario

3d Ultrasound In The Management Of Post Hemorrhagic Ventricle Dilatation, Jessica Kishimoto

Electronic Thesis and Dissertation Repository

Enlargement of the cerebral ventricles is relatively common among extremely preterm neonates born before 28 weeks gestational age. One common cause of ventricle dilatation is post hemorrhagic ventricle dilatation following a bleed in the cerebral ventricles. While many neonates with PHVD will have spontaneous resolution of the condition, severe, persistent PHVD is associated with a greater risk of brain injury and morbidity later in life and left untreated can cause death. The current clinical management strategy consists of daily measurements of head circumference and qualitative interpretation of two-dimensional US images to detect ventricular enlargement and monitoring vital signs for indications ...


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