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Full-Text Articles in Biomedical Engineering and Bioengineering

A Multimodal Approach To Investigate Brain Reorganization After Spinal Cord Injury Using Functional Magnetic Resonance Imaging And Functional Near-Infrared Spectroscopy, Keerthana Deepti Karunakaran May 2019

A Multimodal Approach To Investigate Brain Reorganization After Spinal Cord Injury Using Functional Magnetic Resonance Imaging And Functional Near-Infrared Spectroscopy, Keerthana Deepti Karunakaran

Dissertations

Traumatic Spinal Cord Injury (SCI) results in structural and functional neurological changes at both the brain and the level of the spinal cord. Anatomical studies indicate decreased grey matter volume in sensorimotor and non-sensorimotor regions of the cortex following SCI; whereas, neurophysiological findings mostly report altered functional activity in the sensorimotor nodes of the cortex, subcortex, and cerebellum. Therefore, it is currently unknown whether tissue atrophy observed in non-motor related areas has any concomitant functional consequences. Furthermore, the neural underpinnings of adaptive neuroplasticity after SCI is not well-defined in the current literature. Hence, this dissertation is a pioneer study investigating ...


Computer-Aided Diagnoses (Cad) System: An Artificial Neural Network Approach To Mri Analysis And Diagnosis Of Alzheimer's Disease (Ad), Berizohar Padilla Cerezo Dec 2017

Computer-Aided Diagnoses (Cad) System: An Artificial Neural Network Approach To Mri Analysis And Diagnosis Of Alzheimer's Disease (Ad), Berizohar Padilla Cerezo

Master's Theses and Project Reports

Alzheimer’s disease (AD) is a chronic and progressive, irreversible syndrome that deteriorates the cognitive functions. Official death certificates of 2013 reported 84,767 deaths from Alzheimer’s disease, making it the 6th leading cause of death in the United States. The rate of AD is estimated to double by 2050. The neurodegeneration of AD occurs decades before symptoms of dementia are evident. Therefore, having an efficient methodology for the early and proper diagnosis can lead to more effective treatments.

Neuroimaging techniques such as magnetic resonance imaging (MRI) can detect changes in the brain of living subjects. Moreover, medical imaging ...


Computer-Assisted Characterization Of Prostate Cancer On Magnetic Resonance Imaging, Derek J. Soetemans Mar 2017

Computer-Assisted Characterization Of Prostate Cancer On Magnetic Resonance Imaging, Derek J. Soetemans

Electronic Thesis and Dissertation Repository

Prostate cancer (PCa) is one of the most prevalent cancers among men. Early diagnosis can improve survival and reduce treatment costs. Current inter-radiologist variability for detection of PCa is high. The use of multi-parametric magnetic resonance imaging (mpMRI) with machine learning algorithms has been investigated both for improving PCa detection and for PCa diagnosis. Widespread clinical implementation of computer-assisted PCa lesion characterization remains elusive; critically needed is a model that is validated against a histologic reference standard that is densely sampled in an unbiased fashion. We address this using our technique for highly accurate fusion of mpMRI with whole-mount digitized ...


A Magnetic Resonance Compatible Knee Extension Ergometer, Youssef Jaber Jan 2017

A Magnetic Resonance Compatible Knee Extension Ergometer, Youssef Jaber

Masters Theses

The product of this thesis aims to enable the study of the biochemical and physical dynamics of the lower limbs at high levels of muscle tension and fast contraction speeds. This is accomplished in part by a magnetic resonance (MR) compatible ergometer designed to apply a load as a torque of up to 420 Nm acting against knee extension at speeds as high as 4.7 rad/s. The system can also be adapted to apply the load as a force of up to 1200 N acting against full leg extension. The ergometer is designed to enable the use of ...


A Structural And Functional Analysis Of Human Brain Mri With Attention Deficit Hyperactivity Disorder, Arjun A. Watane Jan 2017

A Structural And Functional Analysis Of Human Brain Mri With Attention Deficit Hyperactivity Disorder, Arjun A. Watane

Honors Undergraduate Theses

Attention Deficit Hyperactivity Disorder (ADHD) affects 5-10% of children worldwide. Its effects are mainly behavioral, manifesting in symptoms such as inattention, hyperactivity, and impulsivity. If not monitored and treated, ADHD may adversely affect a child's health, education, and social life. Furthermore, the neurological disorder is currently diagnosed through interviews and opinions of teachers, parents, and physicians. Because this is a subjective method of identifying ADHD, it is easily prone to error and misdiagnosis. Therefore, there is a clear need to develop an objective diagnostic method for ADHD.

The focus of this study is to explore the use of machine ...


A Cad System For Early Diagnosis Of Autism Using Different Imaging Modalities., Marwa Maher Tawfik Ismail Dec 2016

A Cad System For Early Diagnosis Of Autism Using Different Imaging Modalities., Marwa Maher Tawfik Ismail

Electronic Theses and Dissertations

The term “autism spectrum disorder” (ASD) refers to a collection of neuro-developmental disorders that affect linguistic, behavioral, and social skills. Autism has many symptoms, most prominently, social impairment and repetitive behaviors. It is crucial to diagnose autism at an early stage for better assessment and investigation of this complex syndrome. There have been a lot of efforts to diagnose ASD using different techniques, such as imaging modalities, genetic techniques, and behavior reports. Imaging modalities have been extensively exploited for ASD diagnosis, and one of the most successful ones is Magnetic resonance imaging(MRI),where it has shown promise for the ...


Validation Strategies Supporting Clinical Integration Of Prostate Segmentation Algorithms For Magnetic Resonance Imaging, Maysam Shahedi Bagh Khandan Mar 2016

Validation Strategies Supporting Clinical Integration Of Prostate Segmentation Algorithms For Magnetic Resonance Imaging, Maysam Shahedi Bagh Khandan

Electronic Thesis and Dissertation Repository

Segmentation of the prostate in medical images is useful for prostate cancer diagnosis and therapy guidance. However, manual segmentation of the prostate is laborious and time-consuming, with inter-observer variability. The focus of this thesis was on accuracy, reproducibility and procedure time measurement for prostate segmentation on T2-weighted endorectal magnetic resonance imaging, and assessment of the potential of a computer-assisted segmentation technique to be translated to clinical practice for prostate cancer management. We collected an image data set from prostate cancer patients with manually-delineated prostate borders by one observer on all the images and by two other observers on a subset ...


Toward Magnetic Resonance Only Treatment Planning: Distortion Mitigation And Image-Guided Radiation Therapy Validation, Ryan Glen Price Jan 2016

Toward Magnetic Resonance Only Treatment Planning: Distortion Mitigation And Image-Guided Radiation Therapy Validation, Ryan Glen Price

Wayne State University Dissertations

While MR-only treatment planning has shown promise, there are still several well-known challenges that are currently limiting widespread clinical implementation.

Firstly, MR images are affected by both patient-induced and system-level geometric distortions that can significantly degrade treatment planning accuracy. . In addition, the availability of comprehensive distortion analysis software is currently limited. Also while many groups have been working toward a synthetic CT solution, further study is needed on the implementation of synCTs as the reference datasets for linac-based image-guided radiation therapy (IGRT) to help determine their robustness in an MR-only workflow.

A 36×43×2 cm3 phantom with 255 known ...


Impact Of Acl Injury On Patellar Cartilage Thickness, Ethan Leveillee Jan 2016

Impact Of Acl Injury On Patellar Cartilage Thickness, Ethan Leveillee

Graduate College Dissertations and Theses

ACL injury has been shown to have long-lasting and severe consequences on the different structures of the knee such as the articular cartilage and meniscus. Cartilage thickness changes in particular are indicative of osteoarthritic changes in the tibiofemoral joint. While there has been significant research focused on cartilage changes of the tibia and femur, there has been little work looking at patellar cartilage. The following goals were set forth for this study. First, to establish a robust coordinate system to accurately determine the location and orientation of the patella. Secondly, to determine the effects of ACL injury on patellar cartilage ...


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 ...


Changes In The Ultrastructural Features Of Estrogen Deficient Ovine Bone, Peter Mauer Jan 2014

Changes In The Ultrastructural Features Of Estrogen Deficient Ovine Bone, Peter Mauer

PhD theses

Osteoporosis is “a skeletal disorder characterised by compromised bone strength predis- posing to an increased risk of fracture” (NIH, 2001). Every second woman and every fifth man will suffer an osteoporotic fracture (Kanis et al., 2000). Of all people that suffer an age-related fracture, the current gold standard of osteoporosis diagnosis, DEXA scanning, misclassifies 80% of them to be non-osteoporotic (Sanders et al., 2006). Bone quantity is easily measured, however, bone strength is an interplay of bone quantity and quality — and the latter is hard to determine. More reliable clinical methods to diagnose osteoporosis are needed as well as widening ...


Measuring Brain Iron In Healthy Controls And Accessing Venous Abnormalities In Parkinson's Disease Using Mri, Manju Liu Jan 2014

Measuring Brain Iron In Healthy Controls And Accessing Venous Abnormalities In Parkinson's Disease Using Mri, Manju Liu

Wayne State University Dissertations

Iron plays a key role in a number of brain cellular processes. However, abnormal brain iron regulation correlates with a number of neurodegenerative diseases such as Parkinson's disease, multiple sclerosis and so forth. To further elucidate the involvement of iron in neurodegenerative disorders, a robust in vivo quantitative non-invasive assessment of normal brain iron deposition over time is essential. A variety of magnetic resonance imaging (MRI) methods have been used to quantify iron both in vivo and in vitro non-invasively. We first created the baseline of phase value and ∆R2^* as a function of age in seven gray matter ...


Patient-Specific Modeling Of Adult Acquired Flatfoot Deformity Before And After Surgery, Edward Meade Spratley Dec 2013

Patient-Specific Modeling Of Adult Acquired Flatfoot Deformity Before And After Surgery, Edward Meade Spratley

Theses and Dissertations

The use of computational modeling is an increasingly commonplace technique for the investigation of biomechanics in intact and pathological musculoskeletal systems. Moreover, given the robust and repeatable nature of computer simulation and the prevalence of software techniques for accurate 3-D reconstructions of tissues, the predictive power of these models has increased dramatically. However, there are no patient-specific kinematic models whose function is dictated solely by physiologic soft-tissue constraints, articular shape and contact, and without idealized joint approximations. Moreover, very few models have attempted to predict surgical effects combined with postoperative validation of those predictions. Given this, it is not surprising ...


Automated Segmentation Of Left And Right Ventricles In Mri And Classification Of The Myocarfium Abnormalities, Cyrus (Mohammad Saleh) Nambakhsh Sep 2013

Automated Segmentation Of Left And Right Ventricles In Mri And Classification Of The Myocarfium Abnormalities, Cyrus (Mohammad Saleh) Nambakhsh

Electronic Thesis and Dissertation Repository

A fundamental step in diagnosis of cardiovascular diseases, automated left and right ventricle (LV and RV) segmentation in cardiac magnetic resonance images (MRI) is still acknowledged to be a difficult problem. Although algorithms for LV segmentation do exist, they require either extensive training or intensive user inputs. RV segmentation in MRI has yet to be solved and is still acknowledged a completely unsolved problem because its shape is not symmetric and circular, its deformations are complex and varies extensively over the cardiac phases, and it includes papillary muscles. In this thesis, I investigate fast detection of the LV endo- and ...


Detecting Activity-Evoked Ph Changes In Human Brain, Hye Young Heo Jul 2013

Detecting Activity-Evoked Ph Changes In Human Brain, Hye Young Heo

Theses and Dissertations

Localized pH changes have been suggested to occur in the brain during normal function. However, a lack of methods for non-invasively measuring pH with high spatial and temporal resolution limits current knowledge of brain pH dynamics. Here I report that a magnetic resonance imaging (MRI) strategy named T1 relaxation in the rotating frame (T) is sufficiently sensitive to detect widespread pH changes in the mouse and human brain evoked by systemically manipulating carbon dioxide (CO2) or bicarbonate (HCO3). Moreover, T detected changes suggesting a localized acidosis in the human visual cortex induced by a flashing ...


Accelerating Mri Data Acquisition Using Parallel Imaging And Compressed Sensing, Haifeng Wang Dec 2012

Accelerating Mri Data Acquisition Using Parallel Imaging And Compressed Sensing, Haifeng Wang

Theses and Dissertations

Magnetic Resonance Imaging (MRI) scanners are one of important medical instruments, which can achieve more information of soft issues in human body than other medical instruments, such as Ultrasound, Computed Tomography (CT), Single Photon Emission Computed Tomography (SPECT), Positron Emission Tomography (PET), etc. But MRI's scanning is slow for patience of doctors and patients. In this dissertation, the author proposes some methods of parallel imaging and compressed sensing to accelerate MRI data acquisition. Firstly, a method is proposed to improve the conventional GRAPPA using cross-sampled auto-calibration data. This method use cross-sampled auto-calibration data instead of the conventional parallel-sampled auto-calibration ...


Novel Phantoms And Post-Processing For Diffusion Spectrum Imaging, Vaibhav Juneja May 2012

Novel Phantoms And Post-Processing For Diffusion Spectrum Imaging, Vaibhav Juneja

UT GSBS Dissertations and Theses (Open Access)

High Angular Resolution Diffusion Imaging (HARDI) techniques, including Diffusion Spectrum Imaging (DSI), have been proposed to resolve crossing and other complex fiber architecture in the human brain white matter. In these methods, directional information of diffusion is inferred from the peaks in the orientation distribution function (ODF). Extensive studies using histology on macaque brain, cat cerebellum, rat hippocampus and optic tracts, and bovine tongue are qualitatively in agreement with the DSI-derived ODFs and tractography. However, there are only two studies in the literature which validated the DSI results using physical phantoms and both these studies were not performed on a ...


Computer-Aided, Multi-Modal, And Compression Diffuse Optical Studies Of Breast Tissue, David R. Busch Jr Dec 2011

Computer-Aided, Multi-Modal, And Compression Diffuse Optical Studies Of Breast Tissue, David R. Busch Jr

Publicly Accessible Penn Dissertations

Diffuse Optical Tomography and Spectroscopy permit measurement of important physiological parameters non-invasively through ~10 cm of tissue. I have applied these techniques in measurements of human breast and breast cancer. My thesis integrates three loosely connected themes in this context: multi-modal breast cancer imaging, automated data analysis of breast cancer images, and microvascular hemodynamics of breast under compression. As per the first theme, I describe construction, testing, and the initial clinical usage of two generations of imaging systems for simultaneous diffuse optical and magnetic resonance imaging. The second project develops a statistical analysis of optical breast data from many spatial ...


Chemical And Biological Strategies For Improving The Sensitivity Of Spio-Enhanced Mr Imaging, Andrew Elias Aug 2011

Chemical And Biological Strategies For Improving The Sensitivity Of Spio-Enhanced Mr Imaging, Andrew Elias

Publicly Accessible Penn Dissertations

The prevalence of cancer has seen significant growth over the last three decades, with the American Cancer Society now reporting that one in every three Americans will be afflicted with some form of cancer in their lifetime. The debilitating effects of cancer permeate beyond obvious biological ramifications, often adversely affecting patients on emotional and financial levels as well. While significant progress has been made in diagnosing and treating cancer, advancements are still needed in detecting and treating cancers at earlier stages, where clinical outcomes will be more favorable. The field of cellular and molecular imaging has emerged as a cutting-edge ...


Characterizing Cartilage-Specific T1rho Mri For Clinical Translation And Application, Noelle F. Klocke Jul 2011

Characterizing Cartilage-Specific T1rho Mri For Clinical Translation And Application, Noelle F. Klocke

Theses and Dissertations

T1rho MRI, spin-lattice relaxation in the rotating frame, is postulated to be sensitive to early biochemical changes within articular cartilage that may lead to osteoarthritis. This means that it has potential as a non-invasive, early biomarker for disease progression. However, T1rho has been primarily studied in a research setting. Therefore, the main question posed in this work is:

Can T1rho MRI be used in an at-risk population (ACL-rupture patients) and translated to a clinical setting?

To answer this question, two tools (Relaxometry program, Line Profile Analysis) were created and validated for measuring T1rho within living subjects. These tools were used ...


Traumatic Vs. Pathological Achilles Tendon Ruptures: A Look Into The Importance Of The Collagen Matrix And The Preferred Method Of Repair, Kathleen M. Mclean Jun 2011

Traumatic Vs. Pathological Achilles Tendon Ruptures: A Look Into The Importance Of The Collagen Matrix And The Preferred Method Of Repair, Kathleen M. Mclean

Honors Theses

The Achilles tendon is the largest, strongest, and thickest tendon in the human body. While it may be the strongest, the Achilles tendon is also among one of the most frequently ruptured. These lower limb injuries arise as a result of athletically induced trauma or pathologically and steroidal induced trauma. While the manner in which athletic ruptures occurs can be determined on a case to case basis through the use of clinical examination, ultrasonography, and magnetic resonance imaging (MRI), the method in which the injury should be treated remains controversial. The two main methods of repair include a conservative approach ...


Indirect Detection Of Axonal Architecture With Q-Space Imaging, Henry H. Ong May 2011

Indirect Detection Of Axonal Architecture With Q-Space Imaging, Henry H. Ong

Publicly Accessible Penn Dissertations

Evaluating axon morphology would provide insights into connectivity, maturation, and disease pathology. Conventional diffusion MRI can provide metrics that are related to axon morphology, but cannot measure specific parameters such as mean axon diameter (MAD) and intracellular fraction (ICF). Q-space imaging (QSI) is an advanced diffusion MRI technique that may be able to provide more information on axon morphology. However, QSI has several limitations that affect its implementation and accuracy.

The main objective of this dissertation was to address these limitations and to evaluate the potential of QSI to accurately assess axon morphology. First, a custom-built high-amplitude gradient coil was ...


Sar Map Of Gel Phantom In A 64mhz Mri Birdcage By Fiber-Optic Thermometry And Fdtd Simulation, Chirag Mukesh Patel Feb 2011

Sar Map Of Gel Phantom In A 64mhz Mri Birdcage By Fiber-Optic Thermometry And Fdtd Simulation, Chirag Mukesh Patel

Master's Theses and Project Reports

As implantable medical devices are being used more often to treat medical problems for which pharmaceuticals don’t suffice, it is important to understand their interactions with commonly used medical modalities. The interactions between medical implants and Magnetic Resonance Imaging machines have proven to be a risk for patients with implants.

Implanted medical devices with elongated metallic components can create harmful levels of local heating in a Magnetic Resonance Imaging (MRI) environment [1]. The heating of a biological medium under MRI is monitored via the Specific Absorption Rate (SAR). SAR, defined as power absorbed per unit mass (W/kg), can ...


Investigations Of Anatomical Connectivity In The Internal Capsule Of Macaques With Diffusion Magnetic Resonance Imaging, Kyle Andrew Ignatius Taljan Jan 2011

Investigations Of Anatomical Connectivity In The Internal Capsule Of Macaques With Diffusion Magnetic Resonance Imaging, Kyle Andrew Ignatius Taljan

ETD Archive

Understanding anatomical connectivity is crucial for improving outcomes of deep brain stimulation surgery. Tractography is a promising method for noninvasively investigating anatomical connectivity, but connections between subcortical regions have not been closely examined by this method. As many connections to subcortical regions converge at the internal capsule (IC), we investigate the connectivity through the IC to three subcortical nuclei (caudate, lentiform nucleus, and thalamus) in 6 macaques. We show that a statistical correction for a known distance-related artifact in tractography results in large changes in connectivity patterns. Our results suggest that care should be taken in using tractography to assess ...


Quantitative Molecular Mri Of Intervertebral Disc Degeneration, Chenyang Wang Aug 2010

Quantitative Molecular Mri Of Intervertebral Disc Degeneration, Chenyang Wang

Publicly Accessible Penn Dissertations

Degeneration of the intervertebral disc (IVD) is the most common cause of back-related disability among North American adults. Low-back-pain and associated disability costs the United States more than 100 billion dollars annually in health care expenditures and reduced productivity. The mechanism of IVD degeneration, especially its biomolecular aspect, is poorly understood in an in vivo setting. Thus there is increasingly a need for the non-invasive diagnosis and quantification of IVD degeneration. MRI is a non-invasive imaging modality capable of producing contrast sensitive to biomolecules. Therefore, the primary objective of this dissertation research project is to develop MRI techniques capable of ...


Imaging The Vasculature With Susceptibility Weighted Imaging: Applications And Analysis, Samuel Barnes Jan 2010

Imaging The Vasculature With Susceptibility Weighted Imaging: Applications And Analysis, Samuel Barnes

Wayne State University Dissertations

Modern magnetic resonance imaging sequences allow detailed non-invasive imaging of both the arteries and veins. This work is divided into four sections that examine different applications and analysis of these sequences.

Susceptibility weighted imaging (SWI) typically generates excellent negative venous contrast. Techniques to generate positive arterial contrast in SWI images without degrading the venous contrast with a single echo are examined. By using high isotropic resolution and high readout bandwidth flow losses can be minimized (generating good arterial contrast) even at the long echo times required for good venous contrast. A downsampling filter is then used to restore lost venous ...


Evaluation Of Upper Motor Neuron Pathology In Amyotrophic Lateral Sclerosis By Mri;Towards Identifying Noninvasive Biomarkers Of The Disease, Venkateswaran Rajagopalan Jan 2010

Evaluation Of Upper Motor Neuron Pathology In Amyotrophic Lateral Sclerosis By Mri;Towards Identifying Noninvasive Biomarkers Of The Disease, Venkateswaran Rajagopalan

ETD Archive

Amyotrophic lateral sclerosis (ALS) is the commonest adult motor neuron disease (MND) which causes progressive muscle paralysis and death usually within 5 years of symptom onset. As a result, only ̃30,000 individuals in the United States are afflicted at any one time even though 5,000 or more individuals are diagnosed yearly. The diagnosis of ALS requires evidence of degeneration in upper motor neurons (UMNs) in the brain and in lower motor neurons (LMNs) that exit the brainstem and spinal cord to innervate skeletal muscles. Diagnosis can be incorrect or delayed when disease is early or atypical because non-invasive ...


Multistructure Segmentation Of Multimodal Brain Images Using Artificial Neural Networks, Eun Young Kim Dec 2009

Multistructure Segmentation Of Multimodal Brain Images Using Artificial Neural Networks, Eun Young Kim

Theses and Dissertations

A method for simultaneously segmenting multiple anatomical brain structures from multi-modal MR images has been developed. An artificial neural network (ANN) was trained from a set of feature vectors created by a combination of high-resolution registration methods, atlas based spatial probability distributions, and a training set of 16 expert traced data sets. A set of feature vectors were adapted to increase performance of ANN segmentation; 1) a modified spatial location for structural symmetry of human brain, 2) neighbors along the priors' descent for directional consistency, and 3) candidate vectors based on the priors for the segmentation of multiple structures. The ...


Imaging Of Tyramine-Substituted Hydrogels For Tissue Replacement, Ediuska V. Laurens Jan 2009

Imaging Of Tyramine-Substituted Hydrogels For Tissue Replacement, Ediuska V. Laurens

ETD Archive

Novel tyramine-based hyaluronan (HA) and collagen hydrogels have been developed in which cross-linking is accomplished via peroxidase-mediated dityramine linkages allowing direct cross-linking in vivo. These TB hydrogels possess advantageous physical properties, which include excellent biocompatibility and the ability to mimic the biological, structural and mechanical properties of normal, healthy tissues, including cartilage, and thus provide for synthetic, implantable biomaterials suitable for a wide range of tissue types. The efficacy of these TB-hydrogels has been previously tested in a number of clinically relevant animal models, which have evaluated their applicability for the repair/replacement of various tissues, including cartilage. Nevertheless, there ...