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Bioimaging and Biomedical Optics Commons™

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Articles 31 - 41 of 41

Full-Text Articles in Bioimaging and Biomedical Optics

Noncontact Diffuse Correlation Tomography Of Breast Tumor, Lian He Jan 2015

Noncontact Diffuse Correlation Tomography Of Breast Tumor, Lian He

Theses and Dissertations--Biomedical Engineering

Since aggressive cancers are frequently hypermetabolic with angiogenic vessels, quantification of blood flow (BF) can be vital for cancer diagnosis. Our laboratory has developed a noncontact diffuse correlation tomography (ncDCT) system for 3-D imaging of BF distribution in deep tissues (up to centimeters). The ncDCT system employs two sets of optical lenses to project source and detector fibers respectively onto the tissue surface, and applies finite element framework to model light transportation in complex tissue geometries. This thesis reports our first step to adapt the ncDCT system for 3-D imaging of BF contrasts in human breast tumors. A commercial 3-D …

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Diffuse Optical Measurements Of Head And Neck Tumor Hemodynamics For Early Prediction Of Chemo-Radiation Therapy Outcomes, Lixin Dong Jan 2015

Diffuse Optical Measurements Of Head And Neck Tumor Hemodynamics For Early Prediction Of Chemo-Radiation Therapy Outcomes, Lixin Dong

Theses and Dissertations--Biomedical Engineering

Chemo-radiation therapy is a principal modality for the treatment of head and neck cancers, and its efficacy depends on the interaction of tumor oxygen with free radicals. In this study, we adopted a novel hybrid diffuse optical instrument combining a commercial frequency-domain tissue oximeter (Imagent) and a custom-made diffuse correlation spectroscopy (DCS) flowmeter, which allowed for simultaneous measurements of tumor blood flow and blood oxygenation. Using this hybrid instrument we continually measured tumor hemodynamic responses to chemo-radiation therapy over the treatment period of 7 weeks. We also explored monitoring dynamic tumor hemodynamic changes during radiation delivery. Blood flow data analysis …

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Frontal White Matter Integrity In Adults With Down Syndrome With And Without Dementia, David K. Powell, Allison Caban-Holt, Greg A. Jicha, William C. Robertson, Roberta Davis, Brian T. Gold, Frederick A. Schmitt, Elizabeth Head Jul 2014

Frontal White Matter Integrity In Adults With Down Syndrome With And Without Dementia, David K. Powell, Allison Caban-Holt, Greg A. Jicha, William C. Robertson, Roberta Davis, Brian T. Gold, Frederick A. Schmitt, Elizabeth Head

Magnetic Resonance Imaging and Spectroscopy Center Faculty Publications

Adults with Down syndrome (DS) are at high risk for developing Alzheimer's disease after the age of 40 years. To detect white matter (WM) changes in the brain linked to dementia, fractional anisotropy (FA) from diffusion tensor imaging was used. We hypothesized that adults with DS without dementia (DS n = 10), DS with dementia (DSAD n = 10) and age matched non-DS subjects (CTL n = 10) would show differential levels of FA and an association with scores from the Brief Praxis Test and the Severe Impairment Battery. WM integrity differences in DS compared with CTL were found predominantly …

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Stabilization Of Extended Diffuse Optical Spectroscopy Measurements On In Vivo Human Skeletal Muscle During Dynamic Exercise, Brad A. Henry Jan 2014

Stabilization Of Extended Diffuse Optical Spectroscopy Measurements On In Vivo Human Skeletal Muscle During Dynamic Exercise, Brad A. Henry

Theses and Dissertations--Biomedical Engineering

This research investigates various applications of diffuse correlation spectroscopy (DCS) on in-vivo human muscle tissue, both at rest and during dynamic exercise. Previously suspected muscle tissue relative blood flow (rBF) baseline shift during extended measurement with DCS and DCS-Near infrared spectroscopy (NIRS) hybrid optical systems are verified, quantified, and resolved by redesign of optical probe and alteration in optical probe attachment methodology during 40 minute supine bed rest baseline measurements. We then translate previously developed occlusion techniques, whereby rBF and relative oxygen consumption rV̇O2 are calibrated to initial resting absolute values by use of a venous occlusion (VO) and …

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Dopaminergic Modulation Of Memory And Affective Processing In Parkinson Depression, Lee X. Blonder, John T. Slevin, Richard J. Kryscio, Catherine A. Martin, Anders H. Andersen, Charles D Smith, Frederick A. Schmitt Nov 2013

Dopaminergic Modulation Of Memory And Affective Processing In Parkinson Depression, Lee X. Blonder, John T. Slevin, Richard J. Kryscio, Catherine A. Martin, Anders H. Andersen, Charles D Smith, Frederick A. Schmitt

Magnetic Resonance Imaging and Spectroscopy Center Faculty Publications

Depression is common in Parkinson's disease and is associated with cognitive impairment. Dopaminergic medications are effective in treating the motor symptoms of Parkinson's disease; however, little is known regarding the effects of dopaminergic pharmacotherapy on cognitive function in depressed Parkinson patients. This study examines the neuropsychological effects of dopaminergic pharmacotherapy in Parkinsonian depression. We compared cognitive function in depressed and non-depressed Parkinson patients at two time-points: following overnight withdrawal and after the usual morning regimen of dopaminergic medications. A total of 28 non-demented, right-handed patients with mild to moderate idiopathic Parkinson's disease participated. Ten of these patients were depressed according …

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Noninvasive Near-Infrared Diffuse Optical Monitoring Of Cerebral Hemodynamics And Autoregulation, Ran Cheng Jan 2013

Noninvasive Near-Infrared Diffuse Optical Monitoring Of Cerebral Hemodynamics And Autoregulation, Ran Cheng

Theses and Dissertations--Biomedical Engineering

Many cerebral diseases are associated with abnormal cerebral hemodynamics and impaired cerebral autoregulation (CA). CA is a mechanism to maintain cerebral blood flow (CBF) stable when mean arterial pressure (MAP) fluctuates. Evaluating these abnormalities requires direct measurements of cerebral hemodynamics and MAP. Several near-infrared diffuse optical instruments have been developed in our laboratory for hemodynamic measurements including near-infrared spectroscopy (NIRS), diffuse correlation spectroscopy (DCS), hybrid NIRS/DCS, and dual-wavelength DCS flow-oximeter. We utilized these noninvasive technologies to quantify CBF and cerebral oxygenation in different populations under different physiological conditions/manipulations. A commercial finger plethysmograph was used to continuously monitor MAP. For investigating …

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Recovering Local Neural Tract Directions And Reconstructing Neural Pathways In High Angular Resolution Diffusion Mri, Ning Cao Jan 2013

Recovering Local Neural Tract Directions And Reconstructing Neural Pathways In High Angular Resolution Diffusion Mri, Ning Cao

Theses and Dissertations--Computer Science

Magnetic resonance imaging (MRI) is an imaging technique to visualize internal structures of the body. Diffusion MRI is an MRI modality that measures overall diffusion effect of molecules in vivo and non-invasively. Diffusion tensor imaging (DTI) is an extended technique of diffusion MRI. The major application of DTI is to measure the location, orientation and anisotropy of fiber tracts in white matter. It enables non-invasive investigation of major neural pathways of human brain, namely tractography. As spatial resolution of MRI is limited, it is possible that there are multiple fiber bundles within the same voxel. However, diffusion tensor model is …

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Towards Omni-Tomography -- Grand Fusion Of Multiple Modalities For Simultaneous Interior Tomography, Ge Wang, Jie Zhang, Hao Gao, Victor Weir, Hengyong Yu, Wenxiang Cong, Xiaochen Xu, Haiou Shen, James Bennett, Mark Furth, Yue Wang, Michael Vannier Jun 2012

Towards Omni-Tomography -- Grand Fusion Of Multiple Modalities For Simultaneous Interior Tomography, Ge Wang, Jie Zhang, Hao Gao, Victor Weir, Hengyong Yu, Wenxiang Cong, Xiaochen Xu, Haiou Shen, James Bennett, Mark Furth, Yue Wang, Michael Vannier

Radiology Faculty Publications

We recently elevated interior tomography from its origin in computed tomography (CT) to a general tomographic principle, and proved its validity for other tomographic modalities including SPECT, MRI, and others. Here we propose "omni-tomography", a novel concept for the grand fusion of multiple tomographic modalities for simultaneous data acquisition in a region of interest (ROI). Omni-tomography can be instrumental when physiological processes under investigation are multi-dimensional, multi-scale, multi-temporal and multi-parametric. Both preclinical and clinical studies now depend on in vivo tomography, often requiring separate evaluations by different imaging modalities. Over the past decade, two approaches have been used for multimodality …

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Multimodal Imaging Evidence For Axonal And Myelin Deterioration In Amnestic Mild Cognitive Impairment, Brian T. Gold, Yang Jiang, David K. Powell, Charles D. Smith Jan 2012

Multimodal Imaging Evidence For Axonal And Myelin Deterioration In Amnestic Mild Cognitive Impairment, Brian T. Gold, Yang Jiang, David K. Powell, Charles D. Smith

Neuroscience Faculty Publications

White matter (WM) microstructural declines have been demonstrated in Alzheimer's disease and amnestic mild cognitive impairment (aMCI). However, the pattern of WM microstructural changes in aMCI after controlling for WM atrophy is unknown. Here, we address this issue through joint consideration of aMCI alterations in fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity, as well as macrostructural volume in WM and gray matter compartments. Participants were 18 individuals with aMCI and 24 healthy seniors. Voxelwise analyses of diffusion tensor imaging data was carried out using tract-based spatial statistics (TBSS) and voxelwise analyses of high-resolution structural data was conducted using …

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Use Of Hybrid Diffuse Optical Spectroscopies In Continuous Monitoring Of Blood Flow, Blood Oxygenation, And Oxygen Consumption Rate In Exercising Skeletal Muscle, Katelyn Gurley Jan 2012

Use Of Hybrid Diffuse Optical Spectroscopies In Continuous Monitoring Of Blood Flow, Blood Oxygenation, And Oxygen Consumption Rate In Exercising Skeletal Muscle, Katelyn Gurley

Theses and Dissertations--Biomedical Engineering

This study combines noninvasive hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] with occlusive calibration for continuous measurement of absolute blood flow (BF), tissue blood oxygenation (StO2), and oxygen consumption rate (VO2) in exercising skeletal muscle. Subjects performed rhythmic dynamic handgrip exercise, while an optical probe connected to a hybrid NIRS/DCS flow-oximeter directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and [tHb]), StO2, relative BF (rBF), and relative VO2 (rVO2) in the forearm flexor muscles. Absolute baseline BF and …

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Alterations In Multiple Measures Of White Matter Integrity In Normal Women At High Risk For Alzheimer's Disease, Brian T. Gold, David K. Powell, Anders H. Andersen, Charles D. Smith Oct 2010

Alterations In Multiple Measures Of White Matter Integrity In Normal Women At High Risk For Alzheimer's Disease, Brian T. Gold, David K. Powell, Anders H. Andersen, Charles D. Smith

Neuroscience Faculty Publications

There is evidence that disruption of white matter (WM) microstructure is an early event in the course of Alzheimer's disease (AD). However, the neurobiological bases of WM microstructural declines in presymptomatic AD are unknown. In the present study we address this issue using a multimodal imaging approach to the study of presymptomatic AD. Participants were 37 high-risk (both family history of dementia and one or more APOE4 alleles) women and 20 low-risk (neither family history nor APOE4) women. Groups were matched for age, education, neuropsychological performance, and vascular factors that could affect white matter. Whole-brain analyses of diffusion tensor imaging …

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