Biomedical Photoacoustic Imaging Using Gas-Coupled Laser Acoustic Detection, Jami Johnson

Student Research Initiatives

Several detection methods have been explored for photoacoustic and ultrasound imaging of biological tissues. Piezoelectric transducers are commonly used, which require contact with the sample to be imaged and have limiting bandwidth characteristics. Interferometry detection exhibits improved bandwidth characteristics and resolution, yet generally require complicated optics and the incorporation of a contacting reflective medium. In this paper, we report the use of a noncontact photoacoustic imaging system that does not require the use of a reflective layer. A simple, robust technique known as gas-coupled laser acoustic detection is used, which has previously been applied to evaluation of composite materials. This ...

Delayed Thrombus Resolution And Fibroproliferative Vascular Wound Healing From Deficiency Of Type Iii Collagen: A Paradoxical Mechanism For Tissue Fragility, Amy J. Reid

UT GSBS Dissertations and Theses (Open Access)

Vascular Ehlers-Danlos syndrome is a heritable disease of connective tissue caused by mutations in COL3A1, conferring a tissue deficiency of type III collagen. Cutaneous wounds heal poorly in these patients, and they are susceptible to spontaneous and catastrophic rupture of expansible hollow organs like the gut, uterus, and medium-sized to large arteries, which leads to premature death. Although the predisposition for organ rupture is often attributed to inherent tissue fragility, investigation of arteries from a haploinsufficient Col3a1 mouse model (Col3a1^+/-) demonstrates that mutant arteries withstand even supraphysiologic pressures comparably to wild-type vessels. We hypothesize that injury that elicits occlusive thrombi ...

A Microfluidic Pretreatment Isoelectric Focusing Dc-Field Assisted H-Filter For The Separation Of Charged Particles, Cameron Sean Carroll

Biomedical Eng/General Eng.

Microfluidic devices are small portable diagnostic chips that allow for analysis of a biologic sample at relatively low cost. This makes them ideal for settings where a hospital is unavailable. The microfluidic pretreatment isoelectric focusing DC-field assisted H-filter is a device that allows for the separation of differently charged particles in a biologic sample. It does this by employing the concepts of diffusion, electrophoresis, and isoelectric focusing. This is perfect for isolation of a desired analyte or separation of waste from a sample in order to achieve better diagnostic results. The device was first modeled mathematically and visually using Comsol ...

Parallel Image Processing For High Content Screening Data, Tamnun-E- Mursalin

Open Access Dissertations and Theses

High-content screening (HCS) produces an immense amount of data, often on the scale of Terabytes. This requires considerable processing power resulting in long analysis time. As a result, HCS with a single-core processor system is an inefficient option because it takes a huge amount of time, storage and processing power. The situation is even worse because most of the image processing software is developed in high-level languages which make customization, flexibility and multi-processing features very challenging. Therefore, the goal of the project is to develop a multithreading model in C language. This model will be used to extract subcellular localization ...

Geometrical Analysis And Modeling Of Craniosynostosis, Sahar Shahbazi

Electronic Thesis and Dissertation Repository

Craniosynostosis is a developmental abnormality in skull growth, due to the fusion of one or more sutures\cite{patho}. To accommodate the growing brain. the skull needs to grow quickly in the first few months of life, and most of the growth of the skull at that time occurs at the sutures. Craniosynostosis occurs when one or more sutures are fused in utero, resulting in an abnormal skull shape. Surgical intervention is usually required at a young age, and remodeling of the skull is done for cosmetic reasons as well as to avoid raised intracranial pressure. In order to study ...

Morphometric, Biochemical, And Raman Spectral Analyses Of Muscle Damage In Patients With Peripheral Arterial Disease: Providing Objective Criteria For Diagnosis And Treatment Monitoring, Kim Cluff

Biological Systems Engineering--Dissertations, Theses, and Student Research

Peripheral arterial disease (PAD), which affects approximately 10 million Americans, is characterized by atherosclerosis of the non-coronary arteries. PAD produces a progressive accumulation of ischemic injury to the limbs that is reflected in a gradual worsening in the myofiber morphology and oxidative damage in the gastrocnemius muscle. In this study, we evaluated the hypothesis that quantitative morphological and biochemical parameters of gastrocnemius myofibers change in a consistent manner during the progression of PAD, provide an objective grading of muscle degeneration in the ischemic limb, and correlate to clinical stage of PAD. Myofiber morphometrics were determined precisely with mathematical equations that ...

Implementation Of Magnetic Resonance Elastography For The Investigation Of Traumatic Brain Injuries, Thomas Boulet

Engineering Mechanics Dissertations & Theses

Magnetic resonance elastography (MRE) is a potentially transformative imaging modality allowing local and non-invasive measurement of biological tissue mechanical properties. It uses a specific phase contrast MR pulse sequence to measure induced vibratory motion in soft material, from which material properties can be estimated. Compared to other imaging techniques, MRE is able to detect tissue pathology at early stages by quantifying the changes in tissue stiffness associated with diseases. In an effort to develop the technique and improve its capabilities, two inversion algorithms were written to evaluate viscoelastic properties from the measured displacements fields. The first one was based on ...

A Brain Model For The Study Of Mr Susceptibility Induced Phase Behavior, Sagar Buch

Open Access Dissertations and Theses

MR phase images contain essential information about local magnetic susceptibility sources in the brain, creating a new type of contrast in magnetic resonance imaging (MRI). The goal of this thesis is to demonstrate with a model of the brain how accurately the transformation of phase to susceptibility takes place.

A 3D brain model uses the Forward process to calculate magnetic field perturbations caused by susceptibility properties of the tissues in the model. Homodyne High Pass (HP) filter and SHARP algorithm are used to process the simulated phase images. Similarly, MR magnitude data are simulated using tissue properties such as T ...

Advanced Structural And Functional Magnetic Resonance Imaging In Chronic Low Back Pa, Gavin Jones

Open Access Dissertations and Theses

An objective measure of muscular low back pain (LBP) symptoms eludes clinicians. This study assessed efficacy of magnetic resonance imaging (MRI) of the lumbar multifidus using diffusion tensor imaging (DTI), blood oxygen level dependent (BOLD) signal fractal dimension (FD) analysis and muscle cross sectional area (CSA) in LBP assessment. MRI results were compared to two questionnaires, the Oswestry disability index (ODI) and visual analog score (VAS).

Right-left asymmetry in both DTI metrics and T2-weighted (T2W) CSA were greater in the injured. Also, asymmetry measures were correlated with body mass index (BMI) but not age, height, or level of physical activity ...

Regularized Latent Variable Methods In The Presence Of Structured Noise And Their Application In The Analysis Of Electroencephalogram Data, Siamak Salari Sharif

Open Access Dissertations and Theses

This thesis provides new regression methods for the removal of structured noise in datasets. With multivariable data, the variables and the noise can be both temporally correlated (i.e. auto correlated in time) and contemporaneously correlated (i.e. cross-correlated at the same time). In many occasions it is possible to acquire measurements of the noise, or some function of it, during the data collection. Several new constrained latent variable methods (LVM) that are built upon previous LVM regression frameworks are introduced. These methods make use of the additional information available about the noise to decompose a dataset into basis for ...

A Low Power Electrical Method For Cell Accumulation And Lysis Using Microfluidics, Md. Shehadul Islam

Open Access Dissertations and Theses

Microbiological contamination from bacteria such as Escherichia coli and Salmonella is one of the main reasons for waterborne illness. Real time and accurate monitoring of water is needed in order to alleviate this human health concern. Performing multiple and parallel analysis of biomarkers such as DNA and mRNA that targets different regions of pathogen functionality provides a complete picture of its presence and viability in the shortest possible time. These biomarkers are present inside the cell and need to be extracted for analysis and detection. Hence, lysis of these pathogenic bacteria is an important part in the sample preparation for ...

Metrics For Evaluating Surgical Microscope Usage During Myringotomy, Arefin M. Shamsil

Electronic Thesis and Dissertation Repository

Abstract

Although teaching and learning surgical microscope manoeuvring is a fundamental step in middle ear surgical training, currently there is no objective method to teach or assess this skill. This thesis presents an experimental study designed to implement and test sets of metrics capable of numerically evaluating microscope manoeuvrability and qualitatively assessing surgical expertise of a subject during a middle ear surgery called myringotomy. The experiment involved performing a myringotomy on a fixed cadaveric ear. As participants, experienced ear-nose-throat (ENT) surgeons and ENT surgical residents were invited. While performing the procedure, their microscope manoeuvring motions were captured as translational and ...

Augmented Image-Guidance For Transcatheter Aortic Valve Implantation, Pencilla Lang

Electronic Thesis and Dissertation Repository

The introduction of transcatheter aortic valve implantation (TAVI), an innovative stent-based technique for delivery of a bioprosthetic valve, has resulted in a paradigm shift in treatment options for elderly patients with aortic stenosis. While there have been major advancements in valve design and access routes, TAVI still relies largely on single-plane fluoroscopy for intraoperative navigation and guidance, which provides only gross imaging of anatomical structures. Inadequate imaging leading to suboptimal valve positioning contributes to many of the early complications experienced by TAVI patients, including valve embolism, coronary ostia obstruction, paravalvular leak, heart block, and secondary nephrotoxicity from contrast use.

A ...

Quantification Of Oxygen Saturation Of Venous Vessels Using Susceptibility Mapping, Jin Tang

Open Access Dissertations and Theses

Quantitatively measuring oxygen saturation is important to characterize the physiological or pathological state of tissue function. In this thesis, we demonstrate the possibility of using susceptibility mapping to noninvasively estimate the venous blood oxygen saturation level. Accurate susceptibility quantification is the key to oxygen saturation quantification. Two approaches are presented in this thesis to generate accurate and artifact free susceptibility maps (SM): a regularized inverse filter and a k-space iterative method. Using the regularized inverse filter, with sufficient resolution, major veins in the brain can be visualized. We found that different sized vessels show a different level of contrast depending ...

Two-Dimensional Blood Flow Velocity Estimation Using Ultrasound Speckle Pattern Dependence On Scan Direction And Velocity, Tiantian Xu

Biological Systems Engineering--Dissertations, Theses, and Student Research

Cardiovascular disease is the leading cause death in the United States. Although emergency surgery and medicine can be used for cardiovascular disease treatment, the survivors will suffer for it afterwards. Ultrasound blood flow measurement provides a noninvasive way for cardiovascular diseases diagnosis. In this dissertation, three algorithms for blood flow velocity measurements were investigated and optimized. Feature tracking has been previously proposed for vector velocity measurement. In Chapter 3, the optimal amplitude and time thresholds for feature extraction were investigated to minimize flow estimate variance while providing sufficient spatial and temporal coverage of flow area. A new method of lateral ...

Testing And Validation Of An Autostainer, Nicholas Hanne

Biomedical Eng/General Eng.

Histology performed by Cal Poly students for research projects and labs are currently performed by hand using a dipping technique. This technique is time consuming, expensive, imprecise, and often unrepeatable. Central Coast Pathology donated a Dako Autostainer to the Biomedical Engineering Department that can perform immunohistological stains of up to 48 samples simultaneously using tightly controlled reagent volumes and incubation times. Protocols are programmed into the machine and can be repeated under the same conditions every time with minimal preparation and exposure to potentially dangerous reagents. The autostainer was repaired and validated by comparing PECAM & BBI stains performed on human ...

Symbolic Generation Of Parallel Solvers For Unconstrained Optimization, Jessica L. M. Pavlin

Open Access Dissertations and Theses

In this thesis we consider the need to generate efficient solvers for inverse imaging problems in a way that supports both quality and performance in software, as well as flexibility in the underlying mathematical models. Many problem domains involve large data sizes and rates, and changes in mathematical modelling are limited only by researcher ingenuity and driven by the value of the application. We use a problem in Magnetic Resonance Imaging to illustrate this situation, motivate the need for better software tools and test the tools we develop. The problem is the determination of velocity profiles, think blood-flow patterns, using ...