Digital Commons Network^™

Mri Upgrades At Radiology Associates, Patrick Cheung, Charlene Donlon

Industrial and Manufacturing Engineering

Problem Statement: The MRI machines at Radiology Associates are limiting the company’s ability to expand and compete within the local market. After discussing with technicians and managers at Radiology Associates, we decided to focus on hardware and software upgrades for the MRI machines. With 2 of the 3 locations purchasing new machines in the near future, our focus was on upgrades at the Santa Maria facility. The two machines at this location needed hardware and/or software upgrades to remain on par competitively both within the company and with local scanning options. Flexible coils are beneficial in terms of size, weight, …

Development And Optimization Of 19f-Mri For Tracking Cellular Therapeutics, Jeffrey M. Gaudet

Electronic Thesis and Dissertation Repository

Introduction: This thesis aims to advance magnetic resonance imaging (MRI) for imaging cellular therapeutics. Traditional, proton-based, MRI provides detailed anatomical images, particularly of soft tissue. However, in order to obtain information at a cellular level specialized imaging agents are required to detect the cells of interest. Perfluorocarbons containing non-radioactive fluorine-19 (¹⁹F) are both biologically safe and MR sensitive. Methods: Pre-clinical ¹⁹F-MRI was implemented on a Varian 9.4T MRI scanner, using a dual ¹⁹F/¹H-tuned birdcage volume coil. Mesenchymal stromal cells (MSC) were pre-labeled with a commercial, FDA approved ¹⁹F-perfluorocarbon emulsion, then implanted intramuscularly into …

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 early diagnosis …

An Automated Syringe Pump System For Improving The Reproducibility Of Dynamic Hyperpolarized Mri Phantoms, Harlee G. Harrison

Dissertations & Theses (Open Access)

AN AUTOMATED SYRINGE PUMP SYSTEM FOR IMPROVING THE REPRODUCIBILITY OF DYNAMIC HYPERPOLARIZED MRI PHANTOMS

Harlee Grace Harrison, B.S.

Advisory Professor: James Bankson, Ph.D.

Magnetic Resonance Imaging (MRI) is a powerful tool in the diagnosis of cancer due to its ability to provide good soft tissue contrast and image resolution without the use of ionizing radiation. The use of hyperpolarized pyruvate as a contrast agent for tumor metabolism during MR scans has the potential to provide information about tumor metabolism in vivo that is not available from traditional imaging measurements or any other method. Hyperpolarization is achieved through dynamic nuclear polarization. …

Encapsulated Contrast Agent Markers For Mri-Based Post-Implant Dosimetry, Tze Yee Lim

Dissertations & Theses (Open Access)

Low-dose-rate prostate brachytherapy involves the implantation of tiny radioactive seeds into the prostate to treat prostate cancer. The current standard post-implant imaging modality is computed tomography (CT). On CT images, the radioactive seeds can be distinctively localized but delineation of the prostate and surrounding soft tissue is poor. Magnetic resonance imaging (MRI) provides better prostate and soft tissue delineation, but seed localization is difficult. To aid with seed localization, MRI markers with encapsulated contrast agent that provide positive-contrast on MRI images (Sirius MRI markers; C4 Imaging, Houston, TX) have been proposed to be placed adjacent to the negative-contrast seeds. This …

Assessment Of Post-Treatment Imaging Changes Following Radiotherapy Using Magnetic Susceptibility Techniques, Jean-Guy Belliveau

Electronic Thesis and Dissertation Repository

Radiation therapy (RT) is a common treatment for brain neoplasms and is used alone or in combination with other therapies. The use of RT has been found to be successful in controlling tumors and extending the overall survival of patients; however, there are many unanswered questions regarding radiotherapy effects in the normal brain surrounding or infiltrated by tumor. Changes to the vascular and parenchyma have been documented, and more recently inflammatory mechanisms have been postulated to play a role in radiation injury. Traditional imaging techniques used within the clinic (CT and MRI) are often lacking in their ability to differentiate …

Block Copolymer Based Magnetic Nanoclusters For Cancer-Theranostics: Synthesis, Characterization And In Vitro Evaluation, Hemant M. Vishwasrao

Theses & Dissertations

“There is plenty of room at the bottom”. In this visionary lecture in 1959 Prof. Richard Feynman spoke of the interesting ramifications of working with matter at the atomic scale. Since then, scientists have worked relentlessly towards realizing his vision. The influence of nanobiotechnology on material science and polymer chemistry has given rise to a new field called ‘theranostics’, combining drug delivery and diagnostics within the same nanostructures, thereby enabling simultaneous diagnosis, targeted drug delivery and continued therapy monitoring. Iron oxide nanoparticles (MNPs) are one such class of MRI contrast agents that can be converted into theranostic nanomedicines for cancer …

Cannabis Use And Affective Processing: A Brain Structure Analysis, Kristin E. Maple

Theses and Dissertations

Cannabis is the most commonly used illicit drug amongst adolescents and young adults in the United States. Previously, cannabis and its components have been associated with differences in affective processing and neural functioning. Participants (ages 16-25) were cannabis users and non-users excluded for psychiatric disorders, major medical conditions, and excessive other drug use. A series of multiple regressions examined whether past year cannabis use and cannabis x gender predicted measures of emotional face processing (using the PennCNP affective battery) as well as volumes in bilateral prefrontal, temporal, limbic, and cerebellar regions, as well as frontolimbic white matter tracts. Subsequently, Pearson …

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 …

Breast Cancer Classification Of Mammographic Masses Using Circularity Max Metric, A New Method, Tae Keun Heo

Electronic Theses and Dissertations

Breast cancer classification can be divided into two categories. The first category is a benign tumor, and the other is a malignant tumor. The main purpose of breast cancer classification is to classify abnormalities into benign or malignant classes and thus help physicians with further analysis by minimizing potential errors that can be made by fatigued or inexperienced physicians. This paper proposes a new shape metric based on the area ratio of a circle to classify mammographic images into benign and malignant class. Support Vector Machine is used as a machine learning tool for training and classification purposes. The improved …

Design And Fabrication Of Solid Nitrogen Cooled Mgb2 Based Persistent Magnet For Mri Application, Dipakkumar J. Patel

University of Wollongong Thesis Collection 1954-2016

Physicians and surgeons rely critically on magnetic resonance imaging (MRI) scans to diagnose and treat critical injuries and medical conditions. In an MRI system, high, stable (<0.1 ppm h-1), and uniform (≤10 ppm in 50 cm diameter of spherical volume) magnetic fields are required for obtaining high-resolution images of the human body. The unique possibilities for the operation of superconducting magnets (i.e., persistent-mode) make them ideal for MRI application. Thus, in the majority of commercially available MRI systems, superconducting persistent magnets based on niobium titanium (NbTi) have been used. These magnets, which are cooled in an expensive liquid helium (LHe) bath at 4.2 K, cannot currently be avoided. Thus, the high operation costs of MRI systems obstruct their extensive use in developing and underdeveloped countries.

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 …

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 landmarks …

The Relationship Between Child Adversity, Anxiety Symptoms And White Matter Integrity, Naomi Koliba

UVM Patrick Leahy Honors College Senior Theses

Chronic activation of the stress response during childhood has been proposed to cause long-term maladaptive changes to the structure of stress response systems, resulting in chronic mental illness. This study helps us to understand how maltreatment in children is associated with differences in white matter integrity and how these factors relate to anxiety symptoms in children. Using Diffusional Kurtosis Imaging data, we examined 106 participants, aged 7-16. Approximately half of the participants were recruited through the Department for Children and Families, and had experienced at least one out-of-home placement following a verified instance of abuse or neglect. Associations between white …

Age-Related Differences In Visuomotor Integration As Measured By Object Affordance Effects - A Combined Behavioural And Neurophysiological Investigation, Elisabeth Linnet

School of Psychology Theses

Visuomotor behaviour – from handling simple objects to operating complex devices – is of fundamental importance in our everyday lives, yet there is relatively little evidence as to how healthy ageing affects these processes. A central role is played by the human capacity for reaching and grasping. Grasping an object requires complex visuomotor transformations, including processing of the object’s extrinsic features (it’s spatial location) and intrinsic features (such as size and shape). It has been documented that action relevant intrinsic object properties automatically facilitate specific motor actions despite being task-irrelevant, the so-called object affordance effect. These effects have been demonstrated …

Primary Visual Cortex And Plasticity Following Central Vision Loss, Wesley K. Burge

All ETDs from UAB

Age-related macular degeneration is one of the most common causes of blindness in the industrialized world, and the advanced phase of the disease that causes significant vision impairment affects nearly 2 million individuals in the United States (Friedman et al., 2004). It is characterized by the degeneration and eventual death of retinal photoreceptors in the macula, which is the area of the retina that mediates central vision. The resulting loss of cells often leads to profound deficits in visual function. However, many individuals with age-related macular degeneration learn to use their spared peripheral vision for visual tasks such as reading, …