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Full-Text Articles in Biomedical Engineering and Bioengineering

Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan Jul 2019

Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan

Mechanical Engineering Research Theses and Dissertations

In impact mechanics, the collision between two or more bodies is a common, yet a very challenging problem. Producing analytical solutions that can predict the post-collision motion of the colliding bodies require consistent modeling of the dynamics of the colliding bodies. This dissertation presents a new method for solving the two and multibody impact problems that can be used to predict the post-collision motion of the colliding bodies. Also, we solve the rigid body collision problem of planar kinematic chains with multiple contacts with external surfaces.

In the first part of this dissertation, we study planar collisions of Balls and ...


Feedforward And Feedback Signals In The Olfactory System, Srimoy Chakraborty May 2019

Feedforward And Feedback Signals In The Olfactory System, Srimoy Chakraborty

Theses and Dissertations

The conglomeration of myriad activities in neural systems often results in prominent oscillations. The primary goal of the research presented in this thesis was to study effects of sensory stimulus on the olfactory system of rats, focusing on the olfactory bulb (OB) and the anterior piriform cortex (aPC). Extracellular electrophysiological measurements revealed distinct frequency bands of oscillations in OB and aPC. However, how these oscillatory fluctuations help the animal to process sensory input is not clearly understood. Here we show high frequency oscillations in olfactory bulb carry feedforward signals to anterior piriform cortex whereas feedback from the aPC is predominantly ...


Optical Vortex And Poincaré Analysis For Biophysical Dynamics, Anindya Majumdar Jan 2019

Optical Vortex And Poincaré Analysis For Biophysical Dynamics, Anindya Majumdar

Dissertations, Master's Theses and Master's Reports

Coherent light - such as that from a laser - on interaction with biological tissues, undergoes scattering. This scattered light undergoes interference and the resultant field has randomly added phases and amplitudes. This random interference pattern is known as speckles, and has been the subject of multiple applications, including imaging techniques. These speckle fields inherently contain optical vortices, or phase singularities. These are locations where the intensity (or amplitude) of the interference pattern is zero, and the phase is undefined.

In the research presented in this dissertation, dynamic speckle patterns were obtained through computer simulations as well as laboratory setups involving scattering ...


In Vivo Vascular Imaging With Photoacoustic Microscopy, Hsun-Chia Hsu Aug 2018

In Vivo Vascular Imaging With Photoacoustic Microscopy, Hsun-Chia Hsu

Engineering and Applied Science Theses & Dissertations

Photoacoustic (PA) tomography (PAT) has received extensive attention in the last decade for its capability to provide label-free structural and functional imaging in biological tissue with highly scalable spatial resolution and penetration depth. Compared to modern optical modalities, PAT offers speckle-free images and is more sensitive to optical absorption contrast (with 100% relative sensitivity). By implementing different regimes of optical wavelength, PAT can be used to image diverse light-absorbing biomolecules. For example, hemoglobin is of particular interest in the visible wavelength regime owing to its dominant absorption, and lipids and water are more commonly studied in the near-infrared regime.

In ...


A 3d Simulation Of Leukocyte Adhesion In Blood Flow, Tai-Hsien Wu Jun 2018

A 3d Simulation Of Leukocyte Adhesion In Blood Flow, Tai-Hsien Wu

Dissertations

It has been widely acknowledged that further understanding about the dynamics between blood cells and blood flow can help us gain more knowledge about the causes of diseases and discover more effective treatments. Examples of such dynamics include red blood cell (RBC, or erythrocyte) aggregation, white blood cell (WBC, or leukocyte) margination, and WBC extravasation. WBC extravasation is an important multiple-step process in the inflammatory response and therefore has drawn considerable attention over the past two decades. In this multiple-step process, a WBC undergoes at least four steps, including capture, rolling, firm adhesion, and transmigration, and each step is influenced ...


Radical Social Ecology As Deep Pragmatism: A Call To The Abolition Of Systemic Dissonance And The Minimization Of Entropic Chaos, Arielle Brender May 2018

Radical Social Ecology As Deep Pragmatism: A Call To The Abolition Of Systemic Dissonance And The Minimization Of Entropic Chaos, Arielle Brender

Student Theses 2015-Present

This paper aims to shed light on the dissonance caused by the superimposition of Dominant Human Systems on Natural Systems. I highlight the synthetic nature of Dominant Human Systems as egoic and linguistic phenomenon manufactured by a mere portion of the human population, which renders them inherently oppressive unto peoples and landscapes whose wisdom were barred from the design process. In pursuing a radical pragmatic approach to mending the simultaneous oppression and destruction of the human being and the earth, I highlight the necessity of minimizing entropic chaos caused by excess energy expenditure, an essential feature of systems that aim ...


Developing Wavefront Shaping Techniques For Focusing Through Highly Dynamic Scattering Media, Ashton Hemphill May 2018

Developing Wavefront Shaping Techniques For Focusing Through Highly Dynamic Scattering Media, Ashton Hemphill

Engineering and Applied Science Theses & Dissertations

One of the prime limiting factors of optical imaging in biological applications is the diffusion of light by tissue, which prevents focusing at depths greater than the optical diffusion limit of ~1 mm in soft tissue. This greatly restricts the utility of optical diagnostic and therapeutic techniques, such as optogenetics, microsurgery, optical tweezing, and phototherapy of deep tissue, which require focused light in order to function. Wavefront shaping extends the depth at which optical focusing may be achieved by compensating for phase distortions induced by scattering, allowing for focusing through constructive interference.

However, due to physiological motion, scattering of light ...


Fluorescence Guided Tumor Imaging: Foundations For Translational Applications, Jessica P. Miller May 2018

Fluorescence Guided Tumor Imaging: Foundations For Translational Applications, Jessica P. Miller

Engineering and Applied Science Theses & Dissertations

Optical imaging for medical applications is a growing field, and it has the potential to improve medical outcomes through its increased sensitivity and specificity, lower cost, and small instrumentation footprint as compared to other imaging modalities. The method holds great promise, ranging from direct clinical use as a diagnostic or therapeutic tool, to pre-clinical applications for increased understanding of pathology. Additionally, optical imaging uses non-ionizing radiation which is safe for patients, so it can be used for repeated imaging procedures to monitor therapy, guide treatment, and provide real-time feedback. The versatile features of fluorescence-based optical imaging make it suited for ...


Developing Photoacoustic Tomography Devices For Translational Medicine And Basic Science Research, Tsz Wai Wong May 2018

Developing Photoacoustic Tomography Devices For Translational Medicine And Basic Science Research, Tsz Wai Wong

Engineering and Applied Science Theses & Dissertations

Photoacoustic (PA) tomography (PAT) provides volumetric images of biological tissue with scalable spatial resolutions and imaging depths, while preserving the same imaging contrast—optical absorption. Taking the advantage of its 100% sensitivity to optical absorption, PAT has been widely applied in structural, functional, and molecular imaging, with both endogenous and exogenous contrasts, at superior depths than pure optical methods. Intuitively, hemoglobin has been the most commonly studied biomolecule in PAT due to its strong absorption in the visible wavelength regime.

One of the main focuses of this dissertation is to investigate an underexplored wavelength regime—ultraviolet (UV), which allows us ...


Design & Delivery Of Automated Winston-Lutz Test For Isocentric & Off-Axis Delivery Stability Utilizing Truebeam Developer Mode & Electronic Portal Imaging Device, Mahmoud Mohammad Yaqoub May 2018

Design & Delivery Of Automated Winston-Lutz Test For Isocentric & Off-Axis Delivery Stability Utilizing Truebeam Developer Mode & Electronic Portal Imaging Device, Mahmoud Mohammad Yaqoub

UNLV Theses, Dissertations, Professional Papers, and Capstones

The uncertainties in treatment delivery cannot be ignored in radiation therapy. Thus, the quality assurance QA tests are very important task of the medical physicist in clinical practice. Assuring the coincidence between the mechanical isocenter of the Linear Accelerator (LINAC) and its radiation beams isocenter is one of the most important qualities need to be tested, and the Winston Lust (WL) test is the

most popular technique to perform this task, especially for the treatment modalities which need high precision in beam delivery such as the stereotactic radiosurgery/stereotactic body radiotherapy (SRS/SBRT). The linear accelerator-based SRS/SBRT is a ...


Sex Differences In Lower Limb Biomechanics During A Single-Leg Cut With Body Borne Load, Auralea Carylon Fain May 2018

Sex Differences In Lower Limb Biomechanics During A Single-Leg Cut With Body Borne Load, Auralea Carylon Fain

Boise State University Theses and Dissertations

Introduction: Musculoskeletal injuries are ever-increasing in military personnel, particularly females. These musculoskeletal injuries are attributed to adaptations in lower limb biomechanics while performing routine military tasks, such as a single-leg cut, with the addition of body borne load. However, it is unknown if females and males exhibit similar lower limb biomechanics with the addition of body borne load during these tasks. This study sought to compare the lower limb biomechanical adaptations exhibited by females and males performing a single-leg cut with body borne load. Methods: Eleven females and 17 males had lower limb biomechanics quantified during a single-leg cut with ...


Characterization Of Computed Tomography Radiomic Features Using Texture Phantoms, Muhammad Shafiq Ul Hassan Apr 2018

Characterization Of Computed Tomography Radiomic Features Using Texture Phantoms, Muhammad Shafiq Ul Hassan

Graduate Theses and Dissertations

Radiomics treats images as quantitative data and promises to improve cancer prediction in radiology and therapy response assessment in radiation oncology. However, there are a number of fundamental problems that need to be solved in order to potentially apply radiomic features in clinic. The first basic step in computed tomography (CT) radiomic analysis is the acquisition of images using selectable image acquisition and reconstruction parameters. Radiomic features have shown large variability due to variation of these parameters. Therefore, it is important to develop methods to address these variability issues in radiomic features due to each CT parameter. To this end ...


Can A Comprehensive Transition Plan To Barefoot Running Be The Solution To The Injury Epidemic In American Endurance Runners?, Michael A. Scarlett Jan 2018

Can A Comprehensive Transition Plan To Barefoot Running Be The Solution To The Injury Epidemic In American Endurance Runners?, Michael A. Scarlett

CMC Senior Theses

Fossils belonging to the genus Homo, dating as far back as two million years ago, exhibit uniquely efficient features suggesting that early humans had evolved to become exceptional endurance runners. Although they did not have the cushion or stability-control features provided in our modern day running shoes, our early human ancestors experienced far less of the running-related injuries we experience today. The injury rate has been estimated as high as 90% annually for Americans training for a marathon and as high as 79% annually for all American endurance runners. There is an injury epidemic in conventionally shod populations that does ...


An Application Of M-Matrices To Preserve Bounded Positive Solutions To The Evolution Equations Of Biofilm Models, Richard S. Landry Jr. Dec 2017

An Application Of M-Matrices To Preserve Bounded Positive Solutions To The Evolution Equations Of Biofilm Models, Richard S. Landry Jr.

University of New Orleans Theses and Dissertations

In this work, we design a linear, two step implicit finite difference method to approximate the solutions of a biological system that describes the interaction between a microbial colony and a surrounding substrate. Three separate models are analyzed, all of which can be described as systems of partial differential equations (PDE)s with nonlinear diffusion and reaction, where the biological colony grows and decays based on the substrate bioavailability. The systems under investigation are all complex models describing the dynamics of biological films. In view of the difficulties to calculate analytical solutions of the models, we design here a numerical ...


System Optimization And Iterative Image Reconstruction In Photoacoustic Computed Tomography For Breast Imaging, Yang Lou Dec 2017

System Optimization And Iterative Image Reconstruction In Photoacoustic Computed Tomography For Breast Imaging, Yang Lou

Engineering and Applied Science Theses & Dissertations

Photoacoustic computed tomography(PACT), also known as optoacoustic tomography (OAT), is an emerging imaging technique that has developed rapidly in recent years. The combination of the high optical contrast and the high acoustic resolution of this hybrid imaging technique makes it a promising candidate for human breast imaging, where conventional imaging techniques including X-ray mammography, B-mode ultrasound, and MRI suffer from low contrast, low specificity for certain breast types, and additional risks related to ionizing radiation. Though significant works have been done to push the frontier of PACT breast imaging, it is still challenging to successfully build a PACT breast ...


System Characterizations And Optimized Reconstruction Methods For Novel X-Ray Imaging, Huifeng Guan Dec 2017

System Characterizations And Optimized Reconstruction Methods For Novel X-Ray Imaging, Huifeng Guan

Engineering and Applied Science Theses & Dissertations

In the past decade there have been many new emerging X-ray based imaging technologies developed for different diagnostic purposes or imaging tasks. However, there exist one or more specific problems that prevent them from being effectively or efficiently employed. In this dissertation, four different novel X-ray based imaging technologies are discussed, including propagation-based phase-contrast (PB-XPC) tomosynthesis, differential X-ray phase-contrast tomography (D-XPCT), projection-based dual-energy computed radiography (DECR), and tetrahedron beam computed tomography (TBCT). System characteristics are analyzed or optimized reconstruction methods are proposed for these imaging modalities. In the first part, we investigated the unique properties of propagation-based phase-contrast imaging technique ...


Optogenetic Investigations Of The Prebötzinger Complex: Support For The Dbx1 Core Hypothesis, Francis D. Pham May 2017

Optogenetic Investigations Of The Prebötzinger Complex: Support For The Dbx1 Core Hypothesis, Francis D. Pham

Undergraduate Honors Theses

The preBötzinger complex (preBötC) is the central pattern generator for inspiratory behaviors. Previous studies on perinatal mice and in vitro suggest that Dbx1-derived neurons within the preBötC form the core oscillator. Here, we provide support for the Dbx1 core hypothesis and show that Dbx1-derived neurons are essential for respiratory rhythmogenesis in adult mice. Using optogenetic strategies, we transiently hyperpolarized Dbx1 neurons of the preBötC in vitro and in adult mice. In both cases, the inspiratory rhythm was disrupted. It is possible that axons from Dbx1 neurons projecting into the preBötC were also hyperpolarized, leading to disfacilitation. To determine if this ...


Low Temperature Plasma For The Treatment Of Epithelial Cancer Cells, Soheila Mohades Apr 2017

Low Temperature Plasma For The Treatment Of Epithelial Cancer Cells, Soheila Mohades

Electrical & Computer Engineering Theses & Disssertations

Biomedical applications of low temperature plasmas (LTP) may lead to a paradigm shift in treating various diseases by conducting fundamental research on the effects of LTP on cells, tissues, organisms (plants, insects, and microorganisms). This is a rapidly growing interdisciplinary research field that involves engineering, physics, life sciences, and chemistry to find novel solutions for urgent medical needs. Effects of different LTP sources have shown the anti-tumor properties of plasma exposure; however, there are still many unknowns about the interaction of plasma with eukaryotic cells which must be elucidated in order to evaluate the practical potential of plasma in cancer ...


Design Of Radio-Frequency Arrays For Ultra-High Field Mri, Ian R O Connell Jan 2017

Design Of Radio-Frequency Arrays For Ultra-High Field Mri, Ian R O Connell

Electronic Thesis and Dissertation Repository

Magnetic Resonance Imaging (MRI) is an indispensable, non-invasive diagnostic tool for the assessment of disease and function. As an investigational device, MRI has found routine use in both basic science research and medicine for both human and non-human subjects.

Due to the potential increase in spatial resolution, signal-to-noise ratio (SNR), and the ability to exploit novel tissue contrasts, the main magnetic field strength of human MRI scanners has steadily increased since inception. Beginning in the early 1980’s, 0.15 T human MRI scanners have steadily risen in main magnetic field strength with ultra-high field (UHF) 8 T MRI systems ...


Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel Jan 2017

Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel

Doctoral Dissertations

A uniform dispersion of reactants is necessary to achieve a complete reaction involving multi-components, especially for the crosslinking of rigid high-performance materials. In these reactions, miscibility is crucial for curing efficiency. This miscibility is typically enhanced by adding a third component, a plasticizer. For the reaction of the highly crystalline crosslinking agent hexamethylenetetramine (HMTA) with a strongly hydrogen-bonded phenol formaldehyde resin, furfural has been traditionally used as the plasticizer. However, the reason for its effectiveness is not clear. In this doctoral thesis work, miscibility and crosslinking efficiency of plasticizers in phenolic curing reactions are studied by thermal analysis and spectroscopic ...


Quantitative Optical Studies Of Oxidative Stress In Rodent Models Of Eye And Lung Injuries, Zahra Ghanian Dec 2016

Quantitative Optical Studies Of Oxidative Stress In Rodent Models Of Eye And Lung Injuries, Zahra Ghanian

Theses and Dissertations

Optical imaging techniques have emerged as essential tools for reliable assessment of organ structure, biochemistry, and metabolic function. The recognition of metabolic markers for disease diagnosis has rekindled significant interest in the development of optical methods to measure the metabolism of the organ.

The objective of my research was to employ optical imaging tools and to implement signal and image processing techniques capable of quantifying cellular metabolism for the diagnosis of diseases in human organs such as eyes and lungs. To accomplish this goal, three different tools, cryoimager, fluorescent microscope, and optical coherence tomography system were utilized to study the ...


Dynamic Holography In Semiconductors And Biomedical Optics, Hao Sun Dec 2016

Dynamic Holography In Semiconductors And Biomedical Optics, Hao Sun

Open Access Dissertations

Three-dimensional scanning and display are rapidly-advancing new technologies with important commercial drivers such as 3D printing and remote imaging for big data applications. Holography is a natural approach to recording and displaying three-dimensional information because it uses phase-sensitive interferometry to record interference patterns when a reference beam encounters coherent light arriving from an object. The 3D information is contained in the values of wave optics. Holography is a broad field that goes beyond recording and displaying. For instance, holographic optical elements, which take advantage of holographic imaging principles, perform the functions of lenses, gratings or mirrors. Holographic interferometry is also ...


Nano-Photonic Waveguides For Chemical And Biomedical Sensing, Surya Venkatasekhar Cheemalapati May 2016

Nano-Photonic Waveguides For Chemical And Biomedical Sensing, Surya Venkatasekhar Cheemalapati

Graduate Theses and Dissertations

In this dissertation, advances in the fields of Photonics, and Plasmonics, and specifically, single cell analysis and waveguide sensing will be addressed. The first part of the dissertation is on Finite Difference Time Domain (FDTD) optimization and experimental demonstration of a nano-scale instrument that allows sensing at the cellular and subcellular levels. A new design of plasmonic coupler into a nanoscale waveguide is proposed and optimized using FDTD simulations. Following this, a subcellular nanoendoscope that can locally excite fluorescence in labelled cell organelles and collect the emitted fluorescent light for detailed spectrum analysis is fabricated and tested. The nanoendoscope has ...


Increasing 18f-Fdg Pet/Ct Capabilities In Radiotherapy For Lung And Esophageal Cancer Via Image Feature Analysis, Jasmine Alexandria Oliver Mar 2016

Increasing 18f-Fdg Pet/Ct Capabilities In Radiotherapy For Lung And Esophageal Cancer Via Image Feature Analysis, Jasmine Alexandria Oliver

Graduate Theses and Dissertations

Positron Emission Tomography (PET) is an imaging modality that has become increasingly beneficial in Radiotherapy by improving treatment planning (1). PET reveals tumor volumes that are not well visualized on computed tomography CT or MRI, recognizes metastatic disease, and assesses radiotherapy treatment (1). It also reveals areas of the tumor that are more radiosensitive allowing for dose painting - a non-homogenous dose treatment across the tumor (1). However, PET is not without limitations. The quantitative unit of PET images, the Standardized Uptake Value (SUV), is affected by many factors such as reconstruction algorithm, patient weight, and tracer uptake time (2). In ...


Fe3o4 Nanoparticles For Magnetic Hyperthermia And Drug Delivery: Synthesis, Characterization And Cellular Studies, Maheshika Palihawadana Arachchige Jan 2016

Fe3o4 Nanoparticles For Magnetic Hyperthermia And Drug Delivery: Synthesis, Characterization And Cellular Studies, Maheshika Palihawadana Arachchige

Wayne State University Dissertations

In recent years, magnetic nanoparticles (MNPs), especially superparamagnetic Fe3O4nanoparticles, have attracted a great deal of attention because of their potential applications in biomedicine. Among the other applications, Magnetic hyperthermia (MHT), where localized heating is generated by means of relaxation processes in MNPs when subjected to a radio frequency magnetic field, has a great potential as a non-invasive cancer therapy treatment. Specific absorption rate (SAR), which measures the efficiency of heat generation, depends on magnetic properties of the particles such as saturation magnetization (Ms), magnetic anisotropy (K), particle size distribution, magnetic dipolar interactions, and the rheological properties of the target medium ...


Voxel-Level Absorbed Dose Calculations With A Deterministic Grid-Based Boltzmann Solver For Nuclear Medicine And The Clinical Value Of Voxel-Level Calculations, Justin Mikell Dec 2015

Voxel-Level Absorbed Dose Calculations With A Deterministic Grid-Based Boltzmann Solver For Nuclear Medicine And The Clinical Value Of Voxel-Level Calculations, Justin Mikell

UT GSBS Dissertations and Theses (Open Access)

Voxel-level absorbed dose (VLAD) is rarely calculated for nuclear medicine (NM) procedures involving unsealed sources or 90Y microspheres (YM). The current standard of practice for absorbed dose calculations in NM utilizes MIRD S-values, which 1) assume a uniform distribution in organs, 2) do not use patient specific geometry, and 3) lack a tumor model. VLADs overcome these limitations. One reason VLADs are not routinely performed is the difficulty in obtaining accurate absorbed doses in a clinically acceptable time. The deterministic grid-based Boltzmann solver (GBBS) was recently applied to radiation oncology where it was reported as fast and accurate for both ...


Characterization Of Low Density Intracranial Lesions Using Dual-Energy Computed Tomography, Jessica L. Nute May 2015

Characterization Of Low Density Intracranial Lesions Using Dual-Energy Computed Tomography, Jessica L. Nute

UT GSBS Dissertations and Theses (Open Access)

Calcific and hemorrhagic foci of susceptibility are frequently encountered on routine brain MR studies. Both etiologies cause variations in local magnetic field strength, leading to dark regions on the MR images that cannot be classified. Single-energy CT (SECT) can be used to identify lesions with attenuation over 100 HU as calcific, however lesions with lower attenuation cannot be reliably identified. While calcific lesions are unlikely to cause harm, hemorrhagic lesions carry a risk of subsequent intracranial bleeding; as such, identification of hemorrhage is vital in preventing the inappropriate use of anticoagulant medications in patients with hemorrhagic lesions.

Given there currently ...


Femtosecond Laser Beam Propagation Through Corneal Tissue: Evaluation Of Therapeutic Laser-Stimulated Second And Third-Harmonic Generation, William R. Calhoun Iii Jan 2015

Femtosecond Laser Beam Propagation Through Corneal Tissue: Evaluation Of Therapeutic Laser-Stimulated Second And Third-Harmonic Generation, William R. Calhoun Iii

Theses and Dissertations

One of the most recent advancements in laser technology is the development of ultrashort pulsed femtosecond lasers (FSLs). FSLs are improving many fields due to their unique extreme precision, low energy and ablation characteristics. In the area of laser medicine, ophthalmic surgeries have seen very promising developments. Some of the most commonly performed surgical operations in the world, including laser-assisted in-situ keratomileusis (LASIK), lens replacement (cataract surgery), and keratoplasty (cornea transplant), now employ FSLs for their unique abilities that lead to improved clinical outcome and patient satisfaction.

The application of FSLs in medical therapeutics is a recent development, and although ...


Frequency Domain Ultrasound Waveform Tomography Breast Imaging, Gursharan Singh Sandhu Jan 2015

Frequency Domain Ultrasound Waveform Tomography Breast Imaging, Gursharan Singh Sandhu

Wayne State University Dissertations

Ultrasound tomography is an emerging modality for imaging breast tissue for the detection of disease. Using the principles of full waveform inversion, high-resolution quantitative sound speed and attenuation maps of the breast can be created. In this thesis, we introduce some basic principles of imaging breast disease and the formalism of sound wave propagation. We present numerical methods to model acoustic wave propagation as well methods to solve the corresponding inverse problem. Numerical simulations of sound speed and attenuation reconstructions are used to assess the efficacy of the algorithm. A careful review of the preprocessing techniques needed for the successful ...


Advances In Image Acquisition And Filtering For Mri Neuroimaging At 7 Tesla, Andrew T. Curtis Sep 2014

Advances In Image Acquisition And Filtering For Mri Neuroimaging At 7 Tesla, Andrew T. Curtis

Electronic Thesis and Dissertation Repository

Performing magnetic resonance imaging at high magnetic field strength promises many improvements over low fields that are of direct benefit in functional neuroimaging. This includes the possibility of improved signal-to-noise levels, and increased BOLD functional contrast and spatial specificity. However, human MRI at 7T and above suffers from unique engineering challenges that limit the achievable gains. In this thesis, three technological developments are introduced, all of which address separate issues associated with functional magnetic resonance neuroimaging at very high magnetic field strengths.

First, the image homogeneity problem is addressed by investigating methods of RF shimming — modifying the excitation portion of ...