Medicine and Health Sciences 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 …

Experiential Learning Final Report: Ase Leadership And Usri, Lauren Cowell

SASAH 4th Year Capstone and Other Projects: Publications

This reflective journey encapsulates the profound impact of my SASAH experiential learning, encompassing roles as an ASE Transition Leader and a USRI intern during my undergraduate years. From fostering academic growth to developing practical skills applicable in professional settings, this program provided unique opportunities for multidimensional learning. Collaboration emerged as a cornerstone, teaching adaptability, resilience, and the nuances of teamwork. Engaging with professionals contributed to workplace insights and personal growth. The roles undertaken enriched my skill set, from refining public speaking to engaging in collaborative research. The CliftonStrengths framework played a pivotal role, guiding me through challenges and leveraging collective …

The Population-Centered Medical Model: A Theory Of Practice For Public Health And Preventive Medicine, Sudit Ranade

Electronic Thesis and Dissertation Repository

Introduction

Public health physicians occupy a unique place in the fields of both medicine and public health. Trained in each field, and often holding positions of authority in public health systems, public health physicians are sometimes challenged to identify their roles in either field of practice. Public health physicians work to achieve population health, but there has been limited theoretical development in this field of practice.

Objectives

The objective of this research was to develop an empirical theory of practice for public health physicians.

Methods

A literature review of current practice models applicable to public health physicians was performed. A …

The Significance Of Injuries And Anatomical Patterns Of Trauma In Pedestrian And Cyclist Fatalities And Their Association With Motor Vehicle Collision Dynamics And Post-Collision Kinematics, Moheem M. Halari

Electronic Thesis and Dissertation Repository

Deaths from motor vehicle collisions (MVCs) are a major global health concern, with over 1.35 million fatalities reported annually by the United Nations. More than half involve pedestrians, cyclists, and motorcyclists. Post-mortem examinations by pathologists determine the cause of death and mechanisms of injury and play a significant role in the investigation of the deaths of vulnerable road users.

The purpose of this study was to understand the injury patterns sustained by pedestrians and cyclists fatally injured in motor vehicle impacts.

This study reviews the development of injury patterns described in the medical literature and identifies their limitations in the …

Fracture Prediction And Prevention In Individuals With Chronic Kidney Disease, Andrea C.J. Cowan

Electronic Thesis and Dissertation Repository

Patients with chronic kidney disease (CKD) face increased fracture risk yet our understanding and management of this risk remains poor. We conducted three studies using retrospective cohort analysis in Ontario, Canada. We developed a 3-year fracture prediction model for patients receiving dialysis. Secondly, we contrasted fracture rates among patients on SGLT2i or DPP4i medications, stratified by kidney function. Lastly, we examined hypocalcemia incidence post-denosumab prescription, stratified by kidney function.

Findings: The fracture risk tool, incorporating demographic and lab data, performed well (AUC 0.72). SGLT2i did not elevate fracture risk vs. DPP4i (HR 0.95 [95% CI 0.79,1.13]). In those prescribed denosumab, …

About Dying And Death: Thanatology's Place In Medical Curriculum, Jill Dombroski

Electronic Thesis and Dissertation Repository

This study explored how healthcare providers engage in advance care planning and end-of-life care conversations. The research explored what shapes their understanding and the extent to which concepts from thanatology they intuitively bring in, explicitly bring in, and maybe fail to recognize. To achieve this, constructivist grounded theory (CGT) methodology guided the design, data collection, analysis, and interpretation of the findings, which allowed for iteration across interviews and analysis with existing theories and data in the literature. The CGT design encouraged further engagement with the literature in an ongoing iterative fashion as well as with the analysis of the data. …

The Impact Of Access To Oral Health Care On Inadequate Oral Health And Multimorbidity, Luis Limo

Electronic Thesis and Dissertation Repository

The connection between oral health and other non-communicable chronic conditions—commonly referred in the dental literature as the oral-systemic health connection—emphasizes the role of oral health care on both oral diseases and chronic conditions, particularly in vulnerable populations like the elderly. This thesis comprises 2 studies: the first is a systematic review on the impact of oral health care interventions, as an indicator of access to oral health care, on chronic conditions of which their co-existence would result in multimorbidity; the second study is a cross-sectional investigation of the associations between oral health, access to oral health care, and multimorbidity among …

A Comparison Of The Thulium Fiber Laser Versus Holmium:Yag Laser Lithotripsy Of Upper Urinary Tract Calculi: Preliminary Results Of A Randomized Prospective Clinical Trial, Eduardo Gonzalez Cuenca

Electronic Thesis and Dissertation Repository

The Holmium:yttrium-aluminium-garnet (Ho:YAG) laser has become an indispensable tool in Endourology since its introduction in 1995, due to its safe and efficient urinary stone fragmentation capabilities. The Thulium Fiber Laser (TFL), is the latest innovation with early clinical experience suggesting improvements over the Ho:YAG. This prospective, randomized controlled study aims to compare clinical outcomes of Ho:YAG versus TFL lithotripsy for upper urinary tract calculi. Patients undergoing ureteroscopy for renal stones (size 8-20mm, density >600 HU) from a single institution were prospectively recruited.

Thirty-eight patients have been recruited (Ho:YAG=20, TFL=18). The laser-on time (p=.330), total operative time (p …

Fluoroscopic Guided Peritoneal Dialysis Catheter Placement: An Analysis Of Pelvic Catheter Positioning And Early Catheter Flow Dysfunction, David Clark

Electronic Thesis and Dissertation Repository

Fluoroscopic peritoneal dialysis catheter (FPDC) positioning has not been thoroughly evaluated. Using a retrospective cohort of adult patients who underwent FPDC insertion in London, Ontario (Feb 1, 2010 - Aug 1, 2017); we retrieved procedural radiographs measuring the level of intraabdominal radiocontrast to pubic symphysis (IRPS), and catheter tip to pubic symphysis (CTPS). The median (Q1-Q3) distance (millimeters) of IRPS was larger in females [35(25-44)] than males [28(19-37); P=0.001]; but this distance was not associated with variables: Age (years), BMI (Kg/m²), Race, PKD, abdominopelvic surgeries, in correlation/regression analyses. CTPS distance increased with BMI [(β; 95% Confidence Interval …

The Shared Contributions Of The Capsule, Labrum, And Bone On The Suction Seal Of The Hip, Alexander J. Hoffer

Electronic Thesis and Dissertation Repository

The hip capsule, labrum, and bone contribute to hip stability. Abnormalities in these structures are associated with pain and microinstability. Previous studies have quantified the individual stabilizing roles of the capsule and labrum and have associated cam over-resection with decreased hip stability.

The first objective of this thesis was to identify the relative biomechanical contributions of the capsule, labrum, and bone to the hip suction seal, as a representation of hip stability. The second objective was to assess the effectiveness of a labral reconstruction in restoring the suction seal after a cam over-resection.

Ten human cadaveric hips were tested in …

The Role Of Dlc1Β In Attenuating Cardiac Ischemia-Reperfusion Injury During Heart Transplantation, Samantha L. Collings

Electronic Thesis and Dissertation Repository

Cardiac ischemia-reperfusion injury (IRI) occurs intra-operatively during heart transplantation (HTx), underpinning graft survival. Past research implicated the PI3K/Akt1 & RhoA/ROCK pathways in IRI. Rho-GTPase activity/Akt regulates Deleted-in-liver-cancer 1 protein’s beta-isoform (DLC1β). Therefore, we hypothesized that DLC1β overexpression (OE) had anti-apoptotic effects. In vitro, HL-1 cells (mouse cardiomyocytes) received chamber hypoxia-oxygenation reperfusion (H/R) for 24H4R with/without DLC1β plasmid, before collection for protein/mRNA analyses. DLC1β-OE resulted in downregulated pro-apoptotic mRNA expression (Bax/Cycs/Casp3), upregulated protective mRNA targets (BCl2/Akt1) and less late/early apoptosis via flow cytometry. Results were confirmed via H9C2 (rat cardiomyocyte) cell lines. In vivo, C57/BL6 mice received heterotopic HTx with/without DLC1β-OE …

Malperfusion Syndrome In The Setting Of Type A Aortic Dissection, Karama Yaslam Karama Bayamin

Electronic Thesis and Dissertation Repository

Background: Acute Type A aortic dissection (TAAD) patients who experience malperfusion syndrome (MPS) are at the greatest risk of major morbidity and mortality. However, the appropriate timing for open proximal aortic repair in the presence of MPS is still uncertain due to variations in clinical manifestations and diverse treatment approaches.

Methods: We conducted a comprehensive literature review to understand the importance of MPS in the setting of TAAD. Then, we conducted a national survey to understand the perception of cardiovascular surgeons across Canada and their approach for those patients. Furthermore, we performed a retrospective analysis of our local data to …

Shedding Light On Hearing In Coma: Investigating The Applicability Of Functional Near-Infrared Spectroscopy For Assessing Auditory Function And Aiding Prognosis In Patients With Acute Disorders Of Consciousness, Reza Moulavi Ardakani

Electronic Thesis and Dissertation Repository

There is a critical need for a bedside neuroimaging tool to aid in the prediction of functional recovery outcomes for patients with acute disorders of consciousness (DoC) in the early days following severe brain injury. Current neurobehavioral examinations and prognosis tools have limitations in predicting good outcomes, leading to potential mistreatment or premature withdrawal of life support. Functional near-infrared spectroscopy (fNIRS) is a viable candidate for such purposes due to its portability and cost-effectiveness. Auditory processing, viewed as a multi-level and multifaceted brain function, could provide a sensitive and specific marker of residual cognitive function in unresponsive patients. This study …

The Effect Of Kidney Preservation At 10°C With Hemopure And Hydrogen Sulfide Donor, Sodium Thiosulfate, In A Syngeneic Model Of Rat Renal Transplantation, Maria Abou Taka

Electronic Thesis and Dissertation Repository

Kidney transplantation is preferred for patients with end-stage renal disease. The current gold standard for preserving kidneys is static cold storage (SCS) at 4°C in University of Wisconsin (UW) solution. However, SCS contributes to ischemia-reperfusion injury (IRI), which involves cell death and inflammation. Our group showed that SCS of kidneys with hydrogen sulfide donors, like sodium thiosulfate (STS), that reduce tissue injury enhanced kidney survival. Though, there is still a risk of cold renal IRI at 4°C. Recent evidence suggests that preserving organs at 10°C enhanced graft function and survival. Therefore, this thesis will evaluate the effect of 10°C kidney …

Sociodemographic Factors And The Risk Of Paediatric Out-Of-Hospital Cardiac Arrest, Samina Idrees

Electronic Thesis and Dissertation Repository

Paediatric out-of-hospital cardiac arrest (POHCA) is associated with poor survival and severe neurological sequelae. This thesis aims to explore the relationship between sociodemographic factors and POHCA. The findings from our systematic review indicate that there are racial disparities in POHCA risk and in the provision of bystander cardiopulmonary resuscitation. There was little evidence of sociodemographic disparities in bystander defibrillation, survival and neurological outcome, particularly across adjusted analyses. The findings from our case-control study in Ontario, Canada, indicate that children living in marginalized areas have an elevated risk of experiencing POHCA. We also found that children living in northern urban or …

Regulatory Implications Of Inadequately Designed Pimavanserin Drug Trials Published With Risk Of Bias On Expedited Regulatory Approval Processes, Benson Law

Electronic Thesis and Dissertation Repository

The objective of this retrospective critical appraisal study was to determine if the trials submitted to the Food and Drug Administration for the expedited approval of pimavanserin was of sufficient methodological quality to ascertain its safety and efficacy. After the general metrics of the trials were assessed, the Risk of Bias 2 tool and the PRagmatic Explanatory Continuum Indicator Summary tool were employed to evaluate the risk of bias and the design suitability of the trials. This study suggests that the decision to approve pimavanserin for the treatment of Parkinson’s Disease Psychosis failed to meet the threshold of evidence normally …

A Biomechanical Comparison Of A Subacromial Balloon Spacer, Superior Capsular Reconstruction, And A Rigid Subacromial Spacer In A Massive Irreparable Rotator Cuff Cadaveric Model, Devin Ferguson

Electronic Thesis and Dissertation Repository

Massive irreparable rotator cuff tears are a common cause of pain and disability. Several different treatments exist; however, they are associated with poor clinical outcomes and survivorship in younger patients without glenohumeral arthritis. The purpose of this thesis was to compare the impact of a subacromial balloon spacer, superior capsular reconstruction, and a rigid subacromial implant on the glenohumeral kinematics and mechanical efficiency of a massive rotator cuff deficient shoulder. The results indicate that each surgical state improves the glenohumeral kinematics of a massive irreparable rotator cuff tear. The subacromial implant leads to mild overcorrection of humeral head translation. No …

Maturation Of Default Mode Network Functional Connectivity Strength In Utero And The Association With Subcortical Macrostructure: Mapping Brain Ontogeny Supporting Early Cognitive Processing, Susana Correa

Electronic Thesis and Dissertation Repository

The third trimester of gestation is scarcely studied despite this being a key window for the development of learning and memory systems. In a prospective cohort study, 30 pregnant women participated in one or two fetal MR imaging sessions between 28- and 39 weeks of gestational age. Activation time courses were extracted from the default mode (DMN), medial temporal lobe (MTL), and thalamocortical (TCN) networks of the fetal brain. Generalized estimating equations were used to examine the association between the DMN-MTL, DMN-TCV connectivity strength, and subcortical volumes. Increased functional connectivity strength between the DMN-MTL networks was negatively associated with smaller …

Assessing Inflammation In The Pathology Of Knee Osteoarthritis, Zachary J. Koudys

Electronic Thesis and Dissertation Repository

Osteoarthritis (OA) is a joint disease that causes pain, stiffness, and loss of function. Inflammation of the synovium plays a role in the pathology of OA. Macrophages are the dominant immune cells in synovial tissue. Activated macrophages over-express the translocator protein (TSPO). [¹⁸F]FEPPA is a 2^nd generation positron emission tomography (PET) tracer that can target TSPO with high specificity. Hybrid [¹⁸F]FEPPA PET/MRI may enable accurate quantification of macrophage activity in vivo. In this work, [¹⁸F]FEPPA tracer uptake in knee synovial tissue was measured ex vivo using autoradiography and was validated to correlate to …

Vertebral Endplate Structural Defects: Measurement, Prevalence And Associated Factors, Aliyu Lawan

Electronic Thesis and Dissertation Repository

Objective: To synthesize current knowledge on the association of endplate structural defects (EPSD) with back pain (BP), improve EPSD measurement, and investigate EPSD prevalence, distribution, and association with age and body mass index (BMI).

Methods: In study 1, a systematic review was conducted on five databases for studies reporting on the association between EPSD and BP. Studies 2 and 3 used CTs and mCTs of 19 embalmed cadavers to examine the diagnostic accuracy of common EPSD assessment methods, and to develop and validate a novel method. Study 4 used the novel method on 200 adult males’ MRI to estimate EPSD …

Sarcopenia In Head And Neck Cancer: A Prognostic Analysis, Nedeljko Jovanovic

Electronic Thesis and Dissertation Repository

Introduction: In head and neck cancer (HNC), loss of skeletal muscle mass (SMM), or sarcopenia, is a strong prognostic factor for outcomes. However, inconsistencies in its assessment limit our understanding of the relationship between sarcopenia and nutrition-related outcomes. This project evaluated the significance of sarcopenia as described in the literature and as demonstrated in a cohort of HNC patients.

Methods: A scoping review was first conducted followed by a retrospective cohort study with data collected from 194 oropharyngeal carcinoma patients treated with definitive radiation/chemoradiation. Sarcopenia was assessed from computed tomography (CT) imaging at the third cervical vertebra (C3) and the …

The Attainment Of Obstetrical Competency In Postgraduate Family Medicine Training: A Qualitative Study, Nisha Arora

Electronic Thesis and Dissertation Repository

Aims: This study explored the Family Medicine resident experience in working towards their obstetrical competencies from the perspectives of residents and educators.

Methods: Using a qualitative descriptive design, semi-structured interviews were conducted with second-year Family Medicine residents and obstetrical supervisors from one Family Medicine program in Ontario, as well as key informants of Canadian Family Medicine maternity education. Interviews were audio-taped and professionally transcribed. Transcripts were coded and interpreted for common themes.

Findings: There was a disconnect between the intent of the College of Family Physicians of Canada Key Features document, and how it is applied at …

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 …

How We Debrief: An Interpretive Description Of Social Service Community Workers' Experiences, Andrea C. Krywucky

Electronic Thesis and Dissertation Repository

The aim of this research was to understand current practices of debriefing being used or not used in community social service organizations and the presumed frameworks or evidence justifying these practices in London, Ontario. The geographical area under concern has seen an increasing poverty gap, lack of affordable housing, toxic drug crisis, with mental health issues being exasperated by the pandemic. Social service agencies are overwhelmed with caseloads, creating an increase in need of care for frontline workers, as they are the first point of contact for many. This research utilized an interpretive description methodology to explore workers’ experiences and …

Assessing The Impact Of Pregnancy And Birth Factors On The Maternal And Infant Microbiota, Kait F. Al, Laura Allen, Samantha Bedell, Jeremy P. Burton, Barbra De Vrijer

Obstetrics & Gynaecology Publications

Background: The microbiota acquired at birth is known to play an intimate role in later life health and disease and has been shown to be affected by the mode of birth. There has been recent interest in microbiota correction by maternal vaginal seeding in Cesarean section-born infants; however, the safety of this practice has been debated. The aim of this study was to assess how other factors, such as timing of sampling, maternal obesity, vaginal Group B Streptococcus colonization (GBS), and antibiotic exposure, affect the maternal and infant microbiota.

Methods: Maternal vaginal and saliva samples were collected at three time …

Monitoring Intraventricular Hemorrhage In Preterm Infants, Lilian Mn Kebaya

Electronic Thesis and Dissertation Repository

Germinal Matrix-Intraventricular hemorrhage (GMH-IVH) remains a significant cause of adverse neurodevelopmental outcomes in preterm infants. Current management options for GMH-IVH rely on serial 2-dimensional cranial ultrasound (2D cUS) ventricular measurements and clinical signs. A need exists for reliable biomarkers to aid in the early detection of posthemorrhagic ventricular dilatation (PHVD) and cerebral palsy (CP). We incorporated 3-dimensional cranial US (3D cUS) and functional infrared spectroscopy (fNIRS) to monitor ventricle volumes (VV) and spontaneous functional connectivity (sFC) in preterm infants with GMH-IVH. Infants with severe GMH-IVH who underwent cerebrospinal fluid diversion showed larger VV, which correlated with decreased sFC. Our findings …

Development Of An On-Call Assessment Tool For Competency-Based Surgical Training, Eric C. Mitchell

Electronic Thesis and Dissertation Repository

Introduction: A central tenet of competency-based medical education is formative assessment of trainees. There are no assessments examining resident competence on-call, despite this being a significant component of resident training and characterized by less supervision compared to daytime.

Methods: A national survey was conducted to evaluate the state of assessment in Canadian Plastic and Reconstructive Surgery programs. An on-call assessment tool was developed based on a consensus group and was piloted over six months. Validity of the tool was examined through qualitative and quantitative methods.

Results: There were 63 tools completed across ten residents and seven staff physicians. Tool reliability …

Noninvasive Quantification Of Tissue Sodium Concentration In The Kidney Disease Spectrum Using 23na Magnetic Resonance Imaging, Fabio R. Salerno

Electronic Thesis and Dissertation Repository

Chronic kidney disease (CKD), especially when requiring kidney replacement therapy (hemodialysis (HD) and peritoneal dialysis (PD)), is associated with extracellular water expansion with increased total body sodium. Sodium can also be accumulated in tissues independently of extracellular water. Sodium-23 magnetic resonance imaging (²³Na MRI) can quantify the concentration of sodium nuclei in tissues. Applied to the human leg, quantification of tissue sodium concentrations mainly at the skin and muscle level is possible. We hypothesized that increased tissue sodium concentrations exert toxic effects in CKD and dialysis. We aimed to (1) compare tissue sodium concentrations in adults, children and …

Severe Lower Extremity Trauma In Ontario: A Linked Population-Based Analysis, Stephanie M. Kim

Electronic Thesis and Dissertation Repository

Open tibia fractures (OTF) are a management challenge. Admission to a trauma center (TC) and a coordinated approach to bony fixation and soft-tissue reconstruction (STR) have been shown to improve outcomes. The objective of this study was to describe patients who had OTF in Ontario and analyze their outcomes. Linked population data pertaining to patients who had OTF between the years 2009-2020 were examined. Demographic information, admission location, and management course were collected. 4240 patients were found. The mean age was 47, and majority were males. Patients admitted to TC had greater proportion of having Injury Severity Score >15, and …

Fetal Sex Impacts Birth To Placental Weight Ratio And Umbilical Cord Oxygen Values With Implications For Regulatory Mechanisms, Bryan S. Richardson, Akasham Rajagopaul, Barbra De Vrijer, Genevieve Eastabrook, Timothy R.H. Regnault

Obstetrics & Gynaecology Publications

Background: We determined the effect of fetal sex on birth/placental weight and umbilical vein and artery oxygen values with implications for placental efficiency and regulatory mechanisms underlying fetal–placental growth differences. Methods: A hospital database was used to obtain birth/placental weight, cord PO2 and other information on patients delivering between Jan 1, 1990 and Jun 15, 2011 with GA > 34 weeks (N = 69,836). Oxygen saturation was calculated from the cord PO2 and pH data, while fractional O2 extraction was calculated from the oxygen saturation data. The effect of fetal sex on birth/placental weight, cord PO2, O2 saturation, and fractional O2 …