Medicine and Health Sciences Commons^™

Structure And Function Of Long-Covid Evaluated Using Pulmonary Imaging, Harkiran Kaur Kooner

Electronic Thesis and Dissertation Repository

The COVID-19 pandemic has resulted in millions of global respiratory infections, ranging in severity from asymptomatic to fatal. One of the many consequences of the pandemic is the emergence of long-COVID, which is an umbrella term used to describe the long-term sequelae and poor quality-of-life following recovery from acute COVID-19 infection. However, the pathophysiology and mechanisms responsible for the heterogenous manifestation of long-COVID remain poorly understood. Hyperpolarized ¹²⁹Xe magnetic resonance imaging (MRI) provides a non-invasive and radiation-free method to regionally visualize and quantify inhaled gas distribution and ventilation in vivo. A strong foundation for the use of pulmonary …

Flexible Attenuation Fields: Tomographic Reconstruction From Heterogeneous Datasets, Clifford S. Parker

Theses and Dissertations--Computer Science

Traditional reconstruction methods for X-ray computed tomography (CT) are highly constrained in the variety of input datasets they admit. Many of the imaging settings -- the incident energy, field-of-view, effective resolution -- remain fixed across projection images, and the only real variance is in the detector's position and orientation with respect to the scene. In contrast, methods for 3D reconstruction of natural scenes are extremely flexible to the geometric and photometric properties of the input datasets, readily accepting and benefiting from images captured under varying lighting conditions, with different cameras, and at disparate points in time and space. Extending CT …

Idiopathic Acute On Chronic Osteomyelitis Mimicking Metastatic Lesion In Humeral Head: A Case Report, Lucas Marks, Gavin Cobb, Nick Duff, Holli Barber

Continental, MidAmerica, & Mountain Divisions GME Research Day 2024

No abstract provided.

Will Clinical Decision Support Mechanisms Reduce The Amount Of Unnecessary Computed Tomography?, Andrea Ciarmello

Dissertations and Theses

Clinical Decision Support Mechanisms (CDSMs) are to patient safety. When used in Radiology, CDSMs can improve radiation dose, quality assurance, and patient care. When paired with the electronic health record, CDSMs provide clinicians with patient-specific data that will help lower healthcare costs and improve patient outcomes. This study demonstrates how introducing clinical decision support mechanisms in electronic health record software will help improve unnecessary CT scans and hinder patient radiation exposure. The ordering physician can now consistently and reliably choose the proper scan each time.

Feasibility And Clinical Value Of 3-Dimensional Myocardial Deformation Analysis By Computed Tomography In Transcatheter Aortic Valve Replacement Patients, Mohamad Rabbani

Electronic Thesis and Dissertation Repository

Purpose: Multi-phase computed tomography angiography (CTA) for the pre-procedural planning of TAVR presents a unique opportunity to assess 3D myocardial biomechanics. This study aimed to assess the feasibility and predictive utility of 3D myocardial deformation analysis (3D-MDA) based principal strain to predict heart failure or death following TAVR using pre-procedural, multi-phase computed tomography angiography (CTA) datasets.

Methods: Two hundred and five patients undergoing pre-TAVR multi-phase gated CTA followed by successful TAVR were retrospectively identified. Whole heart 3D mesh chamber models were generated followed by 3D-MDA of the left ventricle (LV) to determine global LV minimum principal strain (minPS) for endocardial, …

Completion Times For Computerized Tomography Tests And Walkout Rates In The Emergency Department, Chinyere Rumph

Walden Dissertations and Doctoral Studies

AbstractThe efficiency of the emergency department (ED) is important in the provision of quality patient care, which includes avoiding long wait times for tests and treatments. EDs may be overcrowded and understaffed, leading to increased wait times for tests. One of the areas overwhelmed by increased ED cases concerns the number of requests for computerized tomography (CT) scans, which may result in patients leaving the ED before care is completed. The three research questions for this quantitative study focused on the age of patients and CT scan walkout rates, completion time and CT scan walkout rates, and the number of …

Maturation Of Equine Proximal Sesamoid Bones In Thoroughbred Horses, Angela Maria Mangine

Theses and Dissertations--Veterinary Science

Proximal sesamoid bone (PSB) injuries account for approximately 50% of all fatal catastrophic musculoskeletal injuries in Thoroughbred racehorses. In addition, PSB fractures are not uncommon in Thoroughbred foals and yearlings as a result of energetic or intense free exercise. The ability to interpret some PSB pathology assessments, however, is more difficult given the limited information published on the normal development and maturation of these paired sesamoid bones. In addition, the level of normal variation in PSB morphological and structural parameters within the Thoroughbred population as a function of age, body size, gender, and inter-animal variation are not well documented, complicating …

Use Of Chest Ct To Diagnose Covid-19, Ryan Gilgallon

Student Research Poster Presentations 2021

Use of Computed Tomography (CT) to Diagnose COVID-19

Ryan Gilgallon

Dr. Elaine Halesey, Ed.D., R.T.(R)(QM)

This project explains COVID-19 and the role Computed Tomography (CT) can play in diagnosing patients who have infections. General equipment used, symptoms, findings and abnormalities, methods of early detection, rates of misdiagnosis, advantages of CT, and a case study are also discussed. COVID-19 originated in Wuhan, China and rapidly spread throughout the world being transmitted from human to human, affecting the respiratory system. The most common findings in this project consisted of ground-glass opacities (GGO), fibrous stripes, interlobular septal thickening, and consolidation. Computed Tomography is …

Structural Adaptation Of Equine Proximal Sesamoid Bones To High-Speed Exercise, Kathryn Mary Babiarz

Theses and Dissertations--Veterinary Science

Proximal sesamoid bone (PSB) fractures are one of the most commonly reported catastrophic musculoskeletal injuries (CMI) in Thoroughbred racing. Despite the seriousness of these injuries, an understanding of the structural changes that occur normally within PSBs in response to the biomechanical forces of high-speed exercise and how they relate to pathological events leading to fracture remain limited. To address this critical knowledge gap, PSBs from Thoroughbred horses were analyzed with both computed tomography (CT) and microcomputed tomography (µCT) to assess their morphological and structural parameters. Comparisons were made using samples from the left and right forelimbs of Thoroughbreds of both …

Structure And Function Of Asthma Evaluated Using Pulmonary Imaging, Rachel L. Eddy

Electronic Thesis and Dissertation Repository

Asthma has been understood to affect the airways in a spatially heterogeneous manner for over six decades. Computational models of the asthmatic lung have suggested that airway abnormalities are diffusely and randomly distributed throughout the lung, however these mechanisms have been challenging to measure in vivo using current clinical tools. Pulmonary structure and function are still clinically characterized by the forced expiratory volume in one-second (FEV₁) – a global measurement of airflow obstruction that is unable to capture the underlying regional heterogeneity that may be responsible for symptoms and disease worsening. In contrast, pulmonary magnetic resonance imaging (MRI) …

Flash Cardiac Imaging Of The Coronary Arteries, Cierra Yonchik

Medical Imaging Senior Posters

Single Source Cardiac Computed Tomography (CT) Imaging for evaluation of the coronary arteries occurs in multiple formats; the most common being prospective sequential and retrospective spiral methods. The differences between the two methods include dose to the patient as well as the image acquisition process. Dual source CT or Flashcardiac imaging of the coronary arteries is an additional method currently utilized by many facilities via Siemens® equipment. Dual-source imaging has multiple advantages and few disadvantages. An in-depth comparison between flash (dual-source) imaging and traditional (single-source)cardiac imaging is the purpose of this research.

Assessment Of New Innovations In Pet/Ct For Respiratory Motion Correction, Joseph Meier

Dissertations & Theses (Open Access)

In oncological imaging, Positron Emission Tomography/Computed Tomography (PET/CT) is a vital tool used for stating and treatment response assessment of patients due to its ability to visualize and accurately quantify the bio-distribution of radiolabeled pharmaceuticals. However, due to the long acquisition times, respiratory motion blur is unavoidable in PET images especially in the lower lung and upper abdomen. This leads to reductions in measured radiotracer concentration and lesion detectability all of which can potentially result in incorrect management of patients. Multiple methods exist to correct for respiratory motion but are rarely used in the routine clinical setting because of: 1) …

Automatic Exposure Control During Computed Tomography Scans Of The Head: Effects On Dose And Image Quality, Stephen D. Osborne

Electronic Theses and Dissertations

Automatic exposure control (AEC) is effective at reducing potentially harmful radiation doses without sacrificing image quality for many types of computed tomography (CT) scans. However, there is a need for more information regarding the use of AEC for CT head scans. This study was conducted at Johnson County Community Hospital in Mountain City, TN. Preexisting adult CT head scans (n)60 were randomly selected to form 2 stratified samples, (n)30 each. One sample used a standard protocol, and the other used a protocol with a mA-modulated AEC system, Siemens CARE Dose 4D. Causal-comparative analyses were conducted, and …

Texture Analysis And Machine Learning To Predict Pulmonary Ventilation From Thoracic Computed Tomography, Andrew Westcott

Electronic Thesis and Dissertation Repository

Chronic obstructive pulmonary disease (COPD) leads to persistent airflow limitation, causing a large burden to patients and the health care system. Thoracic CT provides an opportunity to observe the structural pathophysiology of COPD, whereas hyperpolarized gas MRI provides images of the consequential ventilation heterogeneity. However, hyperpolarized gas MRI is currently limited to research centres, due to the high cost of gas and polarization equipment. Therefore, I developed a pipeline using texture analysis and machine learning methods to create predicted ventilation maps based on non-contrast enhanced, single-volume thoracic CT. In a COPD cohort, predicted ventilation maps were qualitatively and quantitatively related …

Applications Of Ct Perfusion-Based Triaging And Prognostication In Acute Ischemic Stroke, Eric A. Wright

Electronic Thesis and Dissertation Repository

CT Perfusion (CTP) is a minimally invasive imaging technique that aids acute ischemic stroke (AIS) triage and prognostication by determining tissue viability based on hemodynamic parameters. The goals of this research are to determine: 1) CTP thresholds for estimation of infarct and penumbra volume, 2) how CTP scan duration impacts infarct and penumbra volume estimates, and 3) reliability of CTP for predicting functional outcomes following intra-arterial therapy (IAT).

Chapter 2 introduced an experimental study for determining ischemia-time dependent thresholds for brain infarction using multimodal imaging in a porcine stroke model that is easier to implement than previous large animal stroke …

Comparative Ultrasonographic And Computed Tomographic Images Of The Adrenal Glands Of Healthy Cats, Panrawee Phoomvuthisarn, Kiatpichet Komin, Nan Choisunirachon

The Thai Journal of Veterinary Medicine

Feline adrenal disorders that affect the size of the adrenal glands can be detected by diagnostic imaging including ultrasonography and Computed Tomography (CT). The objectives of this study were to compare the appearance of the adrenal gland in healthy cats between these two techniques and establish the reference values of the CT dimensions of the adrenal gland in cats. We found that there was no significant difference in the length of both adrenal glands between the two techniques but the cranial and caudal heights of the left adrenal glands and cranial height of the right adrenal gland obtained from the …

An Area Based Fan Beam Projection Model, Richard E. Steele, Jiehua Zhu

Honors College Theses

Area based projection models for computed tomography mitigate raw data errors by treating X-Rays as beams, whereas traditional line based projection models treat an X-Ray like a line, thus generating significant error. In an existing area based fan beam projection model, a rotation matrix, Q, simulates the rotation of the emitter detector pair to reduce computational load, but this introduces approximations by using an approximated rotation matrix. We eliminate approximations by deriving an exact formula for the entries of Q. Using a rotation of axes and by considering the neighboring cells' contributions to the area, the result has formulations for …

High Performance Optical Computed Tomography For Accurate Three-Dimensional Radiation Dosimetry, Kurtis Hendrik Dekker

Electronic Thesis and Dissertation Repository

Optical computed tomography (CT) imaging of radiochromic gel dosimeters is a method for truly three-dimensional radiation dosimetry. Although optical CT dosimetry is not widely used currently due to previous concerns with speed and accuracy, the complexity of modern radiotherapy is increasing the need for a true 3D dosimeter. This thesis reports technical improvements that bring the performance of optical CT to a clinically useful level. New scanner designs and improved scanning and reconstruction techniques are described.

First, we designed and implemented a new light source for a cone-beam optical CT system which reduced the scatter to primary contribution in CT …

Inpatient Utilization Of Computed Tomography: The Influence Of Market, Hospital, And Patient Characteristics, Michael Hanshew

Theses and Dissertations

The use of computed tomography (CT) in the care of patients has grown dramatically since its introduction over 30 years ago. The vast majority of the utilization research has focused on factors associated with the variable use in the outpatient and emergency department settings. This has left much of the inpatient use and variation understudied. This study has multiple aims. The first is to characterize the inpatient variation across multiple states and markets. The second is to evaluate the relationship between inpatient CT use and commercial payers across these areas. The third is to develop a model to evaluate the …

Proposed Practice Change To Perform Ultrasound Lung Scans Immediately Following Upper Extremity Peripheral Nerve Blocks To Rule Out A Pneumothrax, Robert Gaston

Doctoral Projects

Regional anesthesia is a technique that can be used for a variety of surgeries. There are risks involved when regional anesthesia is performed. Specifically when upper extremity nerve blocks are performed a potential complication is a pneumothorax. The purpose of this DNP project was to propose a practice change to perform ultrasound (US) lung scans immediately following upper extremity peripheral nerve blocks to rule out a pneumothorax. A needs assessment was conducted at the host facility to determine if the anesthesia providers were aware that US was a method that could be useful for detection of a pneumothorax. Currently, the …

Social-Ecological Factors Affecting Patient Shield Use Among Radiologic And Computed Tomography Technologists, Megan Housenick-Lee

Electronic Theses and Dissertations

Medical radiation is estimated to contribute to over 200,000 deaths annually. Recent increases in the use of radiation-producing medical imaging examinations have led to increasing cumulative radiation dose to the general public. Multiple measures have been taken to address this alarming trend, including physician education, technologist education on dose reduction, and equipment-facilitated dose reduction techniques. Shield use can reduce the primary beam by up to 95%. Medical imaging technologists are the primary individuals responsible for applying shielding during an examination. Currently, literature shows that technologists are not shielding individuals as often as they should.

After pilot testing, medical imaging technologists …

Radiomics For Response Assessment After Stereotactic Radiotherapy For Lung Cancer, Sarah A. Mattonen

Electronic Thesis and Dissertation Repository

Stereotactic ablative radiotherapy (SABR) is a guideline-specified treatment option for patients with early stage non-small cell lung cancer. After treatment, patients are followed up regularly with computed tomography (CT) imaging to determine treatment response. However, benign radiographic changes to the lung known as radiation-induced lung injury (RILI) frequently occur. Due to the large doses delivered with SABR, these changes can mimic the appearance of a recurring tumour and confound response assessment. The objective of this work was to evaluate the accuracy of radiomics, for prediction of eventual local recurrence based on CT images acquired within 6 months of treatment. A …

Hyperpolarized 3he Magnetic Resonance Imaging Phenotypes Of Chronic Obstructive Pulmonary Disease, Damien Pike

Electronic Thesis and Dissertation Repository

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the world. Identifying clinically relevant COPD phenotypes has the potential to reduce the global burden of COPD by helping to alleviate symptoms, slow disease progression and prevent exacerbation by stratifying patient cohorts and forming targeted treatment plans. In this regard, quantitative pulmonary imaging with hyperpolarized 3He magnetic resonance imaging (MRI) and thoracic computed tomography (CT) have emerged as ways to identify and measure biomarkers of lung structure and function. 3He MRI may be used as a tool to probe both functional and structural properties of the lung …

Isolated Gastric Tuberculosis Mimicking Malignancy, Wasim Memon, Saad Siddiqui

Department of Radiology

Isolated tuberculosis of upper gastrointestinal tract is a rare pathology, often mimicking malignancy in clinical presentation and radiological features. We present a case of middle aged gentleman with isolated tuberculosis of stomach, proven on histopathology and showing remarkable improvement on follow up.

Omental Infarction In A Child, Saad Siddiqui, Anwar Ahmed, Naila Nadeem

Department of Radiology

Omental infarction is a rare cause of acute abdomen in children. Typical findings on imaging establish the diagnosis. We present case of a 7 years old boy who presented with acute right iliac fossa pain with diagnosis of omental infarction on imaging and findings confirmed on laparotomy. Sound knowledge regarding this infrequent cause of acute abdomen in children is necessary for timely diagnosis.

Non-Invasive Determination Of Pre-Clinical Markers Of Cardiovascular Diseases In Low Birth Weight And Maternal Western Diet Guinea Pig Offspring Exposed To A Postnatal Western Diet, Jacky Chiu

Electronic Thesis and Dissertation Repository

Low birth weight (LBW), and maternal Western Diet (WD) consumption have both been independently implicated to increase the risk of developing cardiovascular diseases (CVDs) in later life. These fetal programmed risks are also believed to exacerbate the effects of a postnatal WD pattern. Therefore, resulting in the development of pre-clinical markers of CVDs, such as insulin resistance (IR), coronary circulation disruptions. This thesis aimed to elucidate the roles of sub-optimal in utero growth through placental insufficiency, or chronic maternal WD consumption, and postnatal WD consumption on the long-term programming of CVDs in a guinea pig model. Early pre-clinical markers of …

Characterization Of Low Density Intracranial Lesions Using Dual-Energy Computed Tomography, Jessica L. Nute

Dissertations & Theses (Open Access)

Calcific and hemorrhagic foci of susceptibility are frequently encountered on routine brain MR studies. Both etiologies cause variations in local magnetic field strength, leading to dark regions on the MR images that cannot be classified. Single-energy CT (SECT) can be used to identify lesions with attenuation over 100 HU as calcific, however lesions with lower attenuation cannot be reliably identified. While calcific lesions are unlikely to cause harm, hemorrhagic lesions carry a risk of subsequent intracranial bleeding; as such, identification of hemorrhage is vital in preventing the inappropriate use of anticoagulant medications in patients with hemorrhagic lesions.

Given there currently …

Computer Aided Diagnosis Of Oral Cancer: Using Time-Step Ct Images, Jonathan T. Scott

Masters Theses

"In medical imaging it is a very common practice to use a technique known as Time-Step imaging in patients who might develop cancer. Time-Step imaging it a very powerful technique, however it can lead to unmanageable amounts of image data. Previously the only way to search all of this data was to manually look through all of the files. This had to be done by trained professionals who knew what to look for within the images and make a judgment about the patient based on the images. This paper discusses the development of an algorithm to have a computer search …

Accuracy Of Computed Tomography In Diagnosing Malignancy In Solitary Pulmonary Lesions, Imaad-Ur-Rehman, Wasim Memon, Yousuf Husen, Waseem Akhtar, Raafay Sophie, Muhammad Akbar Baig

Department of Radiology

OBJECTIVE: To evaluate accuracy of Computed Tomography (CT) for diagnosing malignancy in solitary pulmonary lesions (SPLs).

METHODS: A prospective cross-sectional study was conducted from 20-01-2007 to 30-06-2008 at the Radiology department, Aga Khan University Hospital (AKUH) Karachi. Fifty-three patients with solitary pulmonary lesions (SPLs) seen in prior chest x-rays or chest CT scans were referred to radiology department for CT guided biopsy. CT scan was performed for each patient prior to biopsy and CT evaluation of the SPLs was performed followed by CT guided Biopsy. Histopathological diagnosis of the lesion was taken as the gold standard.

RESULTS: CT was found …

Development And Application Of Computational Tools For The Study And Optimization Of Variable Resolution X-Ray (Vrx) Computed Tomography Scanners, David Alejandro Rendon

Theses and Dissertations (ETD)

The overall goal of this project was to develop and apply important computerized aids for the design and implementation of Variable Resolution X-ray (VRX) CT scanners developed at the University of Tennessee, Memphis. VRX scanners take advantage of the “projective compression” principle that allows the same device to image objects of very different sizes with the same level of detail by adjusting the field of view and the reconstruction resolution.

The first part of this project aimed to develop a set of computational tools specifically tailored for the design, implementation and study of VRX scanners. This included creating a reconstruction …