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Biomedical Engineering and Bioengineering Commons™
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- Adaptive Optics (1)
- Complex-valued correlation (1)
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- Control (1)
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Articles 1 - 7 of 7
Full-Text Articles in Biomedical Engineering and Bioengineering
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, …
Structural-Functional Brain Connectivity Underlying Integrative Sensorimotor Function After Stroke, Benjamin Thomas Kalinosky
Structural-Functional Brain Connectivity Underlying Integrative Sensorimotor Function After Stroke, Benjamin Thomas Kalinosky
Dissertations (1934 -)
In this dissertation research project, we demonstrated the relationship between the structural and functional connections across the brain in stroke survivors. We used this information to predict arm function in stroke survivors, suggesting that the tools developed through this research will be useful for prescribing individualized rehabilitation strategies in people after stroke. Current clinical methods for rehabilitating sensorimotor function after stroke are not based on the locus of injury in the brain. Instead, therapies are generalized, treating symptoms such as weakness and spasticity. This results in outcomes that are highly variable, with severity of impairment immediately following stroke as the …
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. …
Quantifying Cross-Scatter Contamination In Biplane Fluoroscopy Motion Analysis Systems, Janelle A. Cross, Ben Mchenry, Taly Gilat-Schmidt
Quantifying Cross-Scatter Contamination In Biplane Fluoroscopy Motion Analysis Systems, Janelle A. Cross, Ben Mchenry, Taly Gilat-Schmidt
Biomedical Engineering Faculty Research and Publications
Biplane fluoroscopy is used for dynamic in vivo three-dimensional motion analysis of various joints of the body. Cross-scatter between the two fluoroscopy systems may limit tracking accuracy. This study measured the magnitude and effects of cross-scatter in biplane fluoroscopic images. Four cylindrical phantoms of 4-, 6-, 8-, and 10-in. diameter were imaged at varying kVp levels to determine the cross-scatter fraction and contrast-to-noise ratio (CNR). Monte Carlo simulations quantified the effect of the gantry angle on the cross-scatter fraction. A cadaver foot with implanted beads was also imaged. The effect of cross-scatter on marker-based tracking accuracy was investigated. Results demonstrated …
Noninvasive Assessment Of Photoreceptor Structure And Function In The Human Retina, Robert Francis Cooper
Noninvasive Assessment Of Photoreceptor Structure And Function In The Human Retina, Robert Francis Cooper
Dissertations (1934 -)
The human photoreceptor mosaic underlies the first steps of vision; thus, even subtle defects in the mosaic can result in severe vision loss. The retina can be examined directly using clinical tools; however these devices lack the resolution necessary to visualize the photoreceptor mosaic. The primary limiting factor of these devices is the optical aberrations of the human eye. These aberrations are surmountable with the incorporation of adaptive optics (AO) to ophthalmoscopes, enabling imaging of the photoreceptor mosaic with cellular resolution. Despite the potential of AO imaging, much work remains before this technology can be translated to the clinic. Metrics …
Characterization Of Two-Dimensional Oculomotor Control During Goal-Directed Eye Movements In Humans, Vincent Dang
Characterization Of Two-Dimensional Oculomotor Control During Goal-Directed Eye Movements In Humans, Vincent Dang
Master's Theses (2009 -)
Oculomotor control is a subset of sensorimotor control that allows humans to make extremely accurate eye movements for ADL. Impairments to oculomotor control can increase the impact of sensorimotor control deficits, especially in neurodegenerative diseases such as MS. Here, a two-dimensional computational control system of saccades and smooth-pursuit eye movements was compiled from literature to systematically characterize oculomotor control in eight visually-healthy humans as a precursor to studying the relationship between oculomotor and sensorimotor control in patient populations. Subjects visually tracked a single dot on a 41 x 30.5 cm monitor in a dark room while eye positions were recorded …
An Fmri Study On Supra-Spinal Contributions To Upper And Lower Limb Motor Control, Shancheng Bao
An Fmri Study On Supra-Spinal Contributions To Upper And Lower Limb Motor Control, Shancheng Bao
Master's Theses (2009 -)
The differences in the neural mechanisms contributing to upper and lower extremity movement have not been fully elucidated, and this might be a factor that leads to the ineffectiveness of rehabilitation techniques for most stroke survivors. It is unclear whether therapies designed for upper extremities should also be used for the lower extremities, and vice versa. In this study, fMRI was used to examine the supraspinal control of UE and LE movement in both neurologically intact individuals and people with post-stroke hemiparesis. We compared the location, volume, and intensity of brain activity associated with upper and lower extremity pedaling and …