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Full-Text Articles in Medicine and Health Sciences
Motion Artifact Evaluation Of Coronary Ct Angiography Images, Hongfeng Ma
Motion Artifact Evaluation Of Coronary Ct Angiography Images, Hongfeng Ma
Dissertations (1934 -)
The objective of this dissertation was to develop and validate an automated algorithm to quantify motion artifact level on coronary CT angiography (CCTA) images. Unlike existing motion artifact reduction techniques that evaluate the relative level of motion artifacts within one exam, this dissertation aims to quantify the absolute level of motion artifacts across exams from varying patients. The ability to quantify absolute motion artifact level enables several potential applications, for example, assessing and comparing two motion artifact reduction techniques. This dissertation includes three specific aims. Aim 1 investigated the absolute motion artifact quantification effectiveness of six motion artifact metrics using …
Muscle Coordination Contributes To Function After Stroke; Proprioception Contributes To Control Of Posture, Movement, Maria Bengtson
Muscle Coordination Contributes To Function After Stroke; Proprioception Contributes To Control Of Posture, Movement, Maria Bengtson
Dissertations (1934 -)
More than half of stroke survivors experience persistent upper extremity motor impairments that can negatively impact quality of life and independence. Effective use of the upper extremity requires coordination of agonist/antagonist muscle pairs, as well as coordination of multiple control actions for stabilizing and moving the arm. In this dissertation, I present three studies in which I recorded isometric torque production, single joint movement and stabilization, and clinical measures of function and impairments after stroke to evaluate the extent to which changes in coordination of agonist/antagonist muscles and of sequential control actions contribute to deficits after stroke. In Aim 1, …
Markerless Kinematics Of Pediatric Manual Wheelchair Mobility, Jacob Robert Rammer
Markerless Kinematics Of Pediatric Manual Wheelchair Mobility, Jacob Robert Rammer
Dissertations (1934 -)
Pediatric manual wheelchair users face substantial risk of orthopaedic injury to the upper extremities, particularly the shoulders, during transition to wheelchair use and during growth and development. Propulsion strategy can influence mobility efficiency, activity participation, and quality of life. The current forefront of wheelchair biomechanics research includes translating findings from adult to pediatric populations, improving the quality and efficiency of care under constrained clinical funding, and understanding injury mechanisms and risk factors. Typically, clinicians evaluate wheelchair mobility using marker-based motion capture and instrumentation systems that are precise and accurate but also time-consuming, inconvenient, and expensive for repeated assessments. There is …
A Fourier Description Of Covariance, And Separation Of Simultaneously Encoded Slices With In-Plane Acceleration In Fmri, Mary C. Kociuba
A Fourier Description Of Covariance, And Separation Of Simultaneously Encoded Slices With In-Plane Acceleration In Fmri, Mary C. Kociuba
Dissertations (1934 -)
Functional magnetic resonance imaging (fMRI) studies aim to identify localized neural regions associated with a cognitive task performed by the subject. An indirect measure of the brain activity is the blood oxygenation level dependent (BOLD) signal fluctuations observed within the complex-valued spatial frequencies measured over time. The standard practice in fMRI is to discard the phase information after image reconstruction, even with evidence of biological task-related change in the phase time-series. In the first aim of this dissertation, a complex-valued time-series covariance is derived as a linear combination of second order temporal Fourier frequency coefficients. As opposed to magnitude-only analysis, …
Injury Risk Assessment Of The Femur In Children With Osteogenesis Imperfecta, Jessica Marie Fritz
Injury Risk Assessment Of The Femur In Children With Osteogenesis Imperfecta, Jessica Marie Fritz
Dissertations (1934 -)
Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and decreased bone mass, which leads to high rates of bone fracture. OI has a prevalence of 1/5,000 to 1/10,000 in the United States. About 90% of persons with OI have a genetic mutation in the coding for collagen type I, which is the major protein of connective tissues, including bone. While its prevalence classifies it as a rare disease, it is the most common disorder of bone etiology. Until recently, little was known about the mechanics and materials of OI bone or their impact on fracture risk. …
Investigation Of Spatio-Temporal Effects Of Fmri Visual Field Mapping Techniques On V1, John J. Janik
Investigation Of Spatio-Temporal Effects Of Fmri Visual Field Mapping Techniques On V1, John J. Janik
Dissertations (1934 -)
Blood oxygenation level dependent functional magnetic resonance imaging has been used extensively for mapping the representation of the visual field within the human brain. Visual field mapping using fMRI has been used clinically to assess patients with cortical pathology and to plan surgical treatment impacting the visual system. The accuracy of fMRI-based visual field mapping methods needs to be better understood for clinical use. This accuracy can be important for presurgical mapping of brain function near a tumor resection site since inaccurate rendition of the underlying neural function could lead to inappropriate resection of viable brain tissue. The most widely …