Analytical, Diagnostic and Therapeutic Techniques and Equipment Commons^™

The Impact Of Simulated Image Acquisition Time Reduction On Image Quality And Parameters Of Myocardial Perfusion Imaging Using A Dedicated Cardiac Camera, Alireza Khatami

Electronic Thesis and Dissertation Repository

Heart disease is the second leading cause of death in Canada, highlighting the crucial role of early diagnosis in disease management. Myocardial perfusion imaging (MPI), is widely employed for this purpose, involves injecting a radiopharmaceutical into the body, imaging its distribution with a gamma camera, and revealing cardiac blood flow patterns. A significant challenge in MPI is the lengthy 8 to 10 minutes required for stress and rest imaging, potentially causing patient discomfort and compromising image quality due to movement. In a clinical study with 26 patients, post-processed data manipulation simulated a reduction in MPI imaging time. The findings indicated …

Improving The Reliability And Accessibility Of Ct Perfusion Imaging In Acute Ischemic Stroke, Kevin J. Chung

Electronic Thesis and Dissertation Repository

CT perfusion (CTP) imaging is a validated treatment decision support tool in acute ischemic stroke. Automated analysis of CTP cerebral blood flow (CBF) and Tmax maps produces estimates of ischemic core and penumbra volumes used to determine target mismatch profiles for treatment. However, availability and utilization of CTP is low due to diagnostic variability between CTP software and technical, logistical, and radiation dose considerations that may limit its routine adoption. The objective of this doctoral research was to improve the reliability and accessibility of CTP by (1) improving diagnostic agreement between CTP software, (2) enabling perfusion imaging with standard acute …

Delineation Of Ascending Aortic Medial Degeneration Using Diffusion Tensor Imaging, Justin A. Ching-Johnson

Electronic Thesis and Dissertation Repository

Thoracic aortic aneurysms (TAAs) are a life-threatening dilation of the thoracic aorta that can lead to catastrophic dissection or rupture. In TAAs, the structure of the aortic wall is perturbed. Current imaging approaches assess lumen dimensions but lack the ability to delineate aortic wall architecture, a key determinant of aortic integrity. Diffusion tensor imaging (DTI) is an MRI modality which can reveal tissue microstructure through diffusion characteristics. In this thesis I investigated the potential for DTI to evaluate TAA architecture. A porcine model of aortic wall degeneration was developed, and DTI scans were performed on healthy and degenerated porcine ascending …

Validation Of Arterial Spin Labeling For Longitudinal Monitoring And Differential Diagnosis Of Frontotemporal Dementia, Tracy Ssali

Electronic Thesis and Dissertation Repository

Frontotemporal dementia (FTD) is a devastating neurodegenerative disease characterized by a rapid decline in behavioural, language, and motor abilities. Advances in the understanding of FTD genetics and pathophysiology, and the subsequent development of novel disease modifying treatments have highlighted the need for tools to assess their efficacy. While structural magnetic resonance imaging (MRI) and functional imaging with ¹⁸F-flurodeoxyglucose (FDG) positron emission tomography (PET) are used for clinical diagnosis, structural changes are subtle at the early stages and PET imaging is expensive and access limited. Given the coupling of cerebral blood flow (CBF) to energy metabolism, an attractive alternative is …

Novel Imaging Tools Reveal The Dynamics Of The Myocardial Growth Hormone Secretagogue Receptor In Heart Disease And Heart Failure, Rebecca Sullivan

Electronic Thesis and Dissertation Repository

Heart disease (HD) is the leading cause of mortality worldwide. Currently, diagnosis is based on clinical features, imaging, and circulating cardiac biomarkers. Cardiac imaging technologies, such as echocardiography and cardiac magnetic resonance imaging (cMRI), enable the non-invasive detection of changes in heart function. Although these modalities can detect changes in structure and anatomy, it is usually at later stages, where prevention may not be possible. In conjunction with imaging, circulating biomarkers of heart failure (HF), notably B-type natriuretic peptide (BNP) and cardiac troponin I and T, can be detected with increased levels in the blood. These biomarkers are associated with …

Estimating Partial Body Ionizing Radiation Exposure By Automated Cytogenetic Biodosimetry, Peter Rogan

Biochemistry Publications

Purpose: Inhomogeneous exposures to ionizing radiation can be detected and quantified with the Dicentric Chromosome Assay (DCA) of metaphase cells. Complete automation of interpretation of the DCA for whole body irradiation has significantly improved throughput without compromising accuracy, however low levels of residual false positive dicentric chromosomes (DCs) have confounded its application for partial body exposure determination.

Materials and Methods: We describe a method of estimating and correcting for false positive DCs in digitally processed images of metaphase cells. Nearly all DCs detected in unirradiated calibration samples are introduced by digital image processing. DC frequencies of irradiated calibration …

Epilepsy Risk Among Survivors Of Intensive Care Unit Hospitalization For Sepsis, Tresah C. Antaya, Britney N. Allen, Lucie Richard, Salimah Z. Shariff, Gustavo Saposnik, Jorge Burneo

Neuroepidemiology Research Unit Project Summaries

Research Summary: Key Findings

• 407 (0.28%) patients developed epilepsy within 2 years of their ICU discharge, 103 (25.3%) of whom were exposed to sepsis.
• Sepsis survivors were significantly more likely to develop epilepsy, relative to non-septic ICU survivors.
• Among sepsis survivors, epilepsy risk increased with age and was higher among those with chronic kidney disease.

Voice Analysis With Iphones: A Low Cost Experimental Solution, Benjamin Van Der Woerd

Electronic Thesis and Dissertation Repository

Background:

Acoustic voice analysis requires a resource intensive setup, including a soundproof booth. This project evaluates smartphone microphone and recording environment impacts on voice sample collection for acoustic voice analysis. A proprietary analysis algorithm is presented for validation.

Methods:

Microphone and recording environment were evaluated using previously collected voice samples presented in four conditions to test two microphones and two recording environments. Prospective samples were used to test the proprietary algorithm, whereby samples were analyzed using this and Praat.

Results:

Microphone and recording environment had small, clinically unimportant impacts on most measurements. The proprietary algorithm reliably analyzed sustained vowels, with …

Ultra-High Field Magnetic Resonance Imaging For Stereotactic Neurosurgery, Jonathan Lau

Electronic Thesis and Dissertation Repository

Stereotactic neurosurgery is a subspecialty within neurosurgery concerned with accurate targeting of brain structures. Deep brain stimulation (DBS) is a specific type of stereotaxy in which electrodes are implanted in deep brain structures. It has proven therapeutic efficacy in Parkinson’s disease and Essential Tremor, but with an expanding number of indications under evaluation including Alzheimer’s disease, depression, epilepsy, and obesity, many more Canadians with chronic health conditions may benefit. Accurate surgical targeting is crucial with millimeter deviations resulting in unwanted side effects including muscle contractions, or worse, vessel injury. Lack of adequate visualization of surgical targets with conventional lower field …

The Effect Of Sepsis On Cerebral Microvascular Blood Flow, Laura Mawdsley, Mamadou Diop, Chris G. Ellis

Western Research Forum

Background: Sepsis is a dysregulated host response to infection that affects 18 000 000 people worldwide, and over 325 000 000 dollars are spent treating sepsis in Canada every year. One of the symptoms of severe sepsis is an altered mental state, which is accompanied with a measured decrease in oxygen levels in the skeletal muscle microvasculature. It is hypothesized that his altered mental state is due to a lack of oxygenated blood reaching the brain.

Hypothesis: After the onset of sepsis, microvascular cerebral blood flow and oxygen levels in the blood will decrease. Onset of decreased blood flow in …

The Risk Of New-Onset Epilepsy And Refractory Epilepsy In Older Adult Stroke Survivors, Jorge G. Burneo, Tresah C. Antaya, Britney N. Allen, Andrea Belisle, Salimah Z. Shariff, Gustavo Saposnik

Neuroepidemiology Research Unit Project Summaries

Research Summary: Key Findings

• Stroke is a common cause of epilepsy in older adults, but little is known about stroke-related epilepsy or its outcomes in this population.
• 1.1% of older adult stroke survivors developed epilepsy in this study, of whom 12.9% developed refractory epilepsy, indicating that this population is particularly responsive to treatment.
• Over 85% of deaths in this population are not due to stroke or epilepsy.

A Randomized Controlled Trial Of A Modified Cystoscopy Technique, Khalil Hetou

Electronic Thesis and Dissertation Repository

Introduction

Pain, anxiety and embarrassment are well documented feelings in patients undergoing ambulatory diagnostic cystoscopy. In this study, we explored utilizing Peak-end theory in improving pain perception in patients undergoing diagnostic cystoscopy.

Materials and Methods

We conducted a randomized clinical trial at the London Health Sciences Center for patients undergoing an ambulatory diagnostic cystoscopy for the first time. Males and females as well as allocation ratios were 1:1. The control arm received a standard cystoscopy. In the intervention arm the cystoscope was left for additional 2 minutes without further manipulation in the bladder before scope removal. The primary outcome was …

Tibiotalar Arthrodesis: Development Of A Novel Jig And Alignment Guide, Adam Mathew Ropchan

Electronic Thesis and Dissertation Repository

Tibiotalar arthrodesis is a surgical procedure, used for the treatment of end-stage ankle arthrosis and instability. There are dozens of described procedures in the literature, all with varying rates of success. Two of the most common reasons for reoperation in tibiotalar arthrodesis are nonunion and infection; few studies have established any associations between patient/surgical factors and reoperation for nonunion and infection.

The first part of this thesis focuses on determining the rate of reoperation to the ipsilateral lower limb and if any patient/surgical factors are associated with reoperation for nonunion and infection. The second part of this thesis turns attention …

Kallikrein-Related Peptidases Are Dysregulated In Pleomorphic Adenoma, Matthew D. Morrison

Electronic Thesis and Dissertation Repository

Objectives: Pleomorphic adenoma (PA) is the most common benign salivary gland tumor. Kallikrein-related peptidases (KLKs) have been identified as biomarkers in many human tumors and may influence tumor behavior. We investigated KLK1-15 messenger ribonucleic acid (mRNA) and proteins in PA specimens to determine a KLK expression profile for this tumor.

Methods: Fresh frozen PA tissue specimens (n = 26) and matched controls were subjected to RT-qPCR to detect KLK1-15 mRNA. Expression of KLK1, KLK12, KLK13 and KLK8 proteins were then evaluated via immunostaining techniques. Statistical analyses were performed with the level of significance set at P < .05.

Results: We observed downregulation …

The Application Of Self-Administered Nutrition Screening Tools And Evaluations Of The Impact Of Malnutrition On Quality Of Life In Individuals With Head And Neck Cancer, Mark J. P. Lynch

Electronic Thesis and Dissertation Repository

Abstract

Background: Individuals with head and neck cancer (HNCa) are at an increased risk of malnutrition. Therefore, self-administered nutrition screens which attempt to address their nutritional concerns may yield benefits for treatment outcomes and quality of life (QOL).

Methods: 34 participants (26 men, 8 women) completed one demographic and two QOL surveys, two nutrition self-screening tools, a nutrition assessment and an ease-of-use questionnaire. Results of the screens were compared to those of the assessment, and relationships between QOL, nutrition status, and demographics were examined.

Results: 32.3% of participants were identified as nutritionally compromised. The sensitivity and specificity for the PG-SGA …

Mechanical Properties Of Retrieved Highly Cross-Linked Polyethylene Acetabular Liners In Total Hip Arthroplasty, Gurpreet Singh

Electronic Thesis and Dissertation Repository

Highly cross-linked polyethylene (HXLPE) has replaced the conventional ultra-high-molecular-weight-polyethylene (UHMWPE) as the gold standard bearing surface in total hip arthroplasty (THA) due to superior wear characteristics and survivorship. However, HXLPE has demonstrated poorer mechanical properties, in vivo oxidation, and concerns of rim fractures. The purpose of this project was to study the mechanical properties at the rim of retrieved HXLPE acetabular liners.

We developed a simple technique for measurement of hardness at the rim of irradiated, remelted, HXLPE liners of a specific design. The effect of shelf time on mechanical properties of retrieved liners was determined and showed no correlation …

Developments In Pet-Mri For Radiotherapy Planning Applications, John Christian Patrick

Electronic Thesis and Dissertation Repository

The hybridization of magnetic resonance imaging (MRI) and positron emission tomography (PET) provides the benefit of soft-tissue contrast and specific molecular information in a simultaneous acquisition. The applications of PET-MRI in radiotherapy are only starting to be realised. However, quantitative accuracy of PET relies on accurate attenuation correction (AC) of, not only the patient anatomy but also MRI hardware and current methods, which are prone to artefacts caused by dense materials. Quantitative accuracy of PET also relies on full characterization of patient motion during the scan. The simultaneity of PET-MRI makes it especially suited for motion correction. However, quality assurance …

Design Of Radio-Frequency Arrays For Ultra-High Field Mri, Ian R O Connell

Electronic Thesis and Dissertation Repository

Magnetic Resonance Imaging (MRI) is an indispensable, non-invasive diagnostic tool for the assessment of disease and function. As an investigational device, MRI has found routine use in both basic science research and medicine for both human and non-human subjects.

Due to the potential increase in spatial resolution, signal-to-noise ratio (SNR), and the ability to exploit novel tissue contrasts, the main magnetic field strength of human MRI scanners has steadily increased since inception. Beginning in the early 1980’s, 0.15 T human MRI scanners have steadily risen in main magnetic field strength with ultra-high field (UHF) 8 T MRI systems deemed to …

Interpretation Of Mutations, Expression, Copy Number In Somatic Breast Cancer: Implications For Metastasis And Chemotherapy, Stephanie Dorman

Electronic Thesis and Dissertation Repository

Breast cancer (BC) patient management has been transformed over the last two decades due to the development and application of genome-wide technologies. The vast amounts of data generated by these assays, however, create new challenges for accurate and comprehensive analysis and interpretation. This thesis describes novel methods for fluorescence in-situ hybridization (FISH), array comparative genomic hybridization (aCGH), and next generation DNA- and RNA-sequencing, to improve upon current approaches used for these technologies. An ab initio algorithm was implemented to identify genomic intervals of single copy and highly divergent repetitive sequences that were applied to FISH and aCGH probe design. FISH …

Methotrexate And Cardiovascular Events, Alpesh Shah

Electronic Thesis and Dissertation Repository

We conducted a systematic review and meta-analysis to assess the association of MTX with cardiovascular morbidity, cardiovascular mortality and all-cause mortality in patients with autoimmune disease. Our primary outcome was incident cardiovascular events. After screening 13,479 citations, we identified a total of 30 eligible studies. We synthesized adjusted risk estimates using a random effects model. MTX was significantly associated with a 25% reduction in cardiovascular events (pooled RR: 0.75, 95% CI: 0.65, 0.86, I²: 11%), a 55% reduction in cardiovascular mortality (0.45, 95% CI: 0.26, 0.80, I²: 33%) and a 40% reduction in all-cause mortality (0.60, …

Ultra High Field (7t) Magnetic Resonance Imaging Of Intracranial Vessel Wall, Pablo Lopez-Ojeda

Electronic Thesis and Dissertation Repository

Intracranial vessel wall imaging may be accomplished with high-field (7T) magnetic resonance (MRI). To determine its feasibility, a 7T MR protocol was defined using Polyvinyl-alcohol cryogel (PVA-C) phantom vessels and healthy subjects.

A 2D matrix construct of PVA-C vessel phantoms of different diameters and wall thicknesses was scanned. Three observers measured the phantom images, one of which three times. Physical measurements were performed using a digital caliper. Ten volunteers were scanned using three different MRI sequences (TSE-3D, FLAIR, MPRAGE). Imaging assessment was performed in different circle of Willis (COW) segments. Reliability and accuracy of the measurements was analyzed by inter …

Complex Shoulder Instability: The Role Of The Latarjet Coracoid Transfer, Ryan Degen

Electronic Thesis and Dissertation Repository

Recurrent anterior shoulder instability is a common clinical entity often requiring surgical stabilization. Recurrence rates following soft-tissue stabilization procedures are moderately high and have been attributed to associated bony defects of either the glenoid or humeral head. Complex shoulder instability, defined as instability associated with bony defects around the shoulder, is a challenging clinical problem. The Latarjet coracoid transfer has been proposed as a treatment option and its resultant stabilizing effects have been explored in this biomechanical cadaver-based study.

For both glenoid and humeral head defects, the Latarjet coracoid transfer adequately stabilized the shoulder, outperforming other procedures often utilized for …

Targeted Sirna Delivery Methods For Rnai-Based Therapies, Di Chen

Electronic Thesis and Dissertation Repository

RNAi has great potential in future therapeutics as it has the ability to regulating many disease-related genes. However, many barriers prevent practical applications. To overcome the barriers, the specific targeting, efficient delivery system, the validated gene and the potent siRNA sequence are all vital important. The studies throughout this thesis have been focued on examining the validation of three RNAi therapies for two different disease models: allergic contact dermatitis and melanoma. For allergic contact dermatitis, I developed and tested a novel topical delivery system for siRNAs targeting TNFα (siTNFα) and MyD88 siRNA (siMyD88). While siRNAs applied without the transdermal enhancer …

Targeted Intracellular Therapeutic Delivery Using Liposomes Formulated With Multifunctional Fast Proteins, Rae L. Nesbitt

Electronic Thesis and Dissertation Repository

Prostate cancer is the most common malignancy in North American men and there is no treatment currently available which offers a clear survival advantage to patients with prostate cancer. We studied liposomes formulated with the fusion-associated small transmembrane (FAST) protein, p14. In this study, we hypothesized that therapeutics delivered in molecular targeted fusogenic liposomes will increase intracellular delivery and specificity for prostate cancer. We demonstrated that liposomes formulated with p14-bombesin significantly increased the delivery of fluorescein isothiocyanate (FITC) into human prostate cancer (PC-3) cells compared to either standard liposomes or non-targeted fusogenic liposomes. Delivery of FITC to benign prostate hyperplasia …