Undergraduate Research Program

2011-12 WRF Fellows

Michael Choi - Biochemistry

Michael Choi pipetteing in labMichael Choi is very interested in biological and biochemical research especially with applications towards medicine and helping patients. Since his freshman year, he has been investigating embryonic stem cells and stem cell maintenance in the Ruohola-Baker laboratory, focusing on the metabolism of embryonic stem cells and how it relates to their function. Stem cells play a critical role in development and disease; by better understanding how these cells function in both normal and pathological conditions, scientists can learn how to control, treat, and cure disorders that arise. His undergraduate research experience and his majors in biochemistry and chemistry with a minor in mathematics have convinced him to pursue a career in science with applications towards medicine. In the future, he is interested in attending graduate school and plans to further investigate the biology of disease and research cures from a biochemical, chemical, and mathematical perspective.

Mentor: Hannele Ruohola-Baker, Biochemistry

Project Title: Characterizing the Metabolism of Embryonic Stem Cells

Abstract: Embryonic stem cells are isolated from the early developing embryo and are capable of forming all of the different cell types found in the body. Understanding how these cells develop and maintain their specialized state is critical to understanding how these cells function. We hypothesize that embryonic stem cells acquire a unique metabolic state that aids them in maintaining their specialized state. Using both mouse and human embryonic stem cells, we investigated their metabolism and how the metabolism changed through different stages of early embryonic development. The metabolic state was characterized by quantifying mitochondria DNA copy number, intracellular adenosine triphosphate levels, and oxygen consumption rates and extracellular acidification rates by a Seahorse Bioanalyzer XF apparatus. We found that later embryonic stem cells compared to early embryonic stem cells utilize much less oxygen and have a much more glycolytic metabolic phenotype despite a greater level of mitochondrial DNA copy numbers. Furthermore, using quantitative polymerase chain reaction experiments, we found that genes key to regulating glycolysis such as lactate dehydrogenase, pyruvate dehydrogenase kinase, and liver glycogen phosphorylase are significantly upregulated in later embryonic stem cells. The metabolic transition between early and later embryonic stem cells may be due to the activity of hypoxia inducible factor 1a (HIF1a), a known key regulator of these glycolytic genes. We show that the overexpression of HIF1a in embryonic stem cells is able to shift the cells towards a more glycolytic metabolic state. Overall, these results indicate that late embryonic stem cells have an increased glycolytic phenotype and that HIF1 is an important regulator of the metabolism of embryonic stem cells.

Kenny Chou - Bioengineering and Electrical Engineering

Kenny Chou in labMedical imaging and minimally invasive modalities had always been an interest of mine. Thinking I’d eventually go into medical school, I started my undergraduate career in Bioengineering. After exposure to the biomedical instrumentation and other technology-orientated classes I realized that I’m more interested in the technology aspect of medicine and decided to pursue a second major in Electrical Engineering. I joined the Human Photonics Lab (HPL) in the summer of 2010 for the CRANE Aerospace sponsored Research Experience for Undergraduates (REU). My first project was to code an image processing operation in a parallel-computing language called the Compute Unified Device Architecture (CUDA), and it introduced me to computational-based research, which I really enjoy doing. My current project is also image processing oriented, and involves processing and registration of 3D Optical Projection Tomography (OPTM) images for tissue biopsy inspection. My project aims to open a new field in biopsy and provide new ways to improve pre-cancer screening, especially for the brain, thyroid, and pancreas. After graduation, I plan to pursue a PhD in Bioengineering with a focus on medical imaging before working in that same industry. I am extremely grateful for the generous support from Washington Research Foundation as it allows me to focus on my research and further motivates me to pursue a career in biomedical imaging.

Mentor: Eric Seibel, Mechanical Engineering

Project Title: Optical Projection Tomography Microscopy for Large Specimen Sizes

Abstract: Many diagnoses are made by observing and analyzing cell and tissue samples under the microscope. Although cell samples can show the presence of a disease, such as cancer, it is more difficult to determine the location, which implies progression, of tumor within a tissue. Since biological architecture is preserved in tissue samples, the location and extent of a disease, which are often the basis for a patient’s treatment, can also be determined. For this project, Thin Needle Core Biopsy (TNCB) will be used to obtain small cylindrical tissue samples 250µm in diameter and up to 2cm in length. The tissue sample will be imaged with Optical Projection Tomography Microscopy (OPTM), which is currently used to generate high-resolution three-dimensional (3D) images of individual cells [1]. Due to limited field of view, large specimen, such as tissue samples, cannot be imaged in their entirety. A series of images will be obtained and stitched together to form a complete reconstruction of the TNCB tissue sample. This project focuses on reconstructing and stitching a series of OPTM images to create a single continuous 3D image of all cells within the entire biopsy. Image processing techniques, such as digital filtering and phase correlation, will also be applied to reduce noise and accurately align images during this process. The ultimate aim of the project is to obtain, construct, and present 3D TNCB tissue images to clinicians in a manner that allows them to make accurate diagnoses and assess cancer invasiveness using this micro-biopsy specimen.

Ben Horst - Mathematics and Chemistry

Ben Horst working in fume hoodAlthough I was not completely certain what I wanted to pursue as a field of study when I came to the University of Washington, I was enthralled with the idea of research and studying something completely new. I found the Keller Lab in the spring of 2010 and have been volunteering and working in their lab ever since. I was ecstatic to be working with Sarah Keller, and the others in the lab; they were studying a relatively new topic in lipid membranes, there a lot of hands on work for me to do, and I was in a lab that was extremely interdisciplinary (we’re a Biophysics lab in the Chemistry Department). I have worked on a variety of projects including refining a new fabrication technique for the formation of vesicles, as well as a collaboration project with the Mougous Lab in the Microbiology Department on Type VI Secretion Systems. I will be starting a new project in the winter and working with a postdoc to determine how miscibility temperature of lipid membranes varies with composition as the surface pressure is held constant.

I know that my time in the Keller Lab will be excellent preparation as I look forward to my Honors Thesis next year, as well as graduate school in the coming years. I have had the opportunity to meet with world renowned scientists in our field, present my own work at a variety of different symposiums on campus, and I will be attending the 2012 Biophysical Society Meeting in San Diego this coming February. I am still undecided as to what my focus will be when it comes to graduate school, but the Keller Lab has inspired me to continue with my education, and contribute to the world of scientific research in any way that I can. I would like to thank the Washington Research Foundation for supporting me as I undertake my second full year of research, as their generosity has afforded me the opportunity to continue to do research as well as continue my other hobbies: marching band and a cappella!

Mentor: Sarah Keller, Chemistry

Project Title: Fabrication of Giant Unilamellar Vesicles – c-DICE

Abstract: A vesicle is a closed lipid bilayer membrane that separates one aqueous solution from another. All cell walls contain a lipid membrane as their base and proteins within the membrane control the transfer of materials and signals in and out of the cell. I am optimizing a recently developed method of vesicle formation called continuous droplet interface crossing encapsulation (c-DICE). This technique utilizes centripetal force to coax water droplets into and out of an oil solution that is saturated with lipids. As each drop enters the oil layer, the hydrophilic heads of the lipids surround the droplet. When the droplet exits, the lipids that surround the water droplet pick up lipids on the outer layer of the oil to form the complete bilayer. After the vesicles are formed, I use microscopic techniques to observe the composition of the vesicle membranes and to assess whether vesicles are leaky. This technique allows vesicles to be made that mimic natural membranes by containing a high fraction of charged lipids and cholesterol, and by containing different lipid compositions on the inner and outer membrane layer (i.e., by being asymmetric), both previously difficult tasks to perform.

Bryce Johnson - Bioengineering and Computer Science

Bryce Johnson working in labI began conducting cardiac regenerative medicine research under the direction of Dr. Michael Regnier in autumn quarter of my sophomore year. Since then, I have developed a significant interest in cardiac physiology and its related diseases, the leading causes of death in the United States. I am currently exploring the effects of cell therapy as a therapeutic to prevent heart failure following myocardial infarction, and I will be designing a device to measure mechanics in intact cardiac trabeculae for my Bioengineering senior capstone project. After college, I hope to attend medical school and later specialize in cardiology. Research has allowed me to work with the forefront of medicine, and I could not be more thankful for the support of the Washington Research Foundation, which will allow me to continue this rewarding experience.

Mentor: Michael Reignier, Bioengineering

Project Title: Design of an appartatus to measure mechanical effects of gene and cell therapy in intact cardiac trabeculae from infarcted hearts

Abstract: This project focuses on understanding function loss due to myocardial infarction and ameliorating this loss via cell therapy. Previously, we have found cell therapy to improve contractility and other function in remote myocardium from infarcted hearts. This project aims to design a device to simultaneously measure intracellular calcium handling and contraction in cardiac trabeculae; these measurements will be compared between healthy, infarcted, and cell-injected myocardium. Myocardial infarction will be induced to Fischer 344 male rats. The first experimental group will be injected with cell-growth media only, while the second experimental group will be injected with a solution of media and neonatal rat cardiomyocytes (NRCs). Sham operated rats (pneumothorax only) will serve as a control group. A device will be designed to measure mechanics of intact cardiac trabeculae. A trabecula will be connected between two T-clips, which are then connected to a length adjustment device and a force transducer; these will allow for the adjustment of sarcomere length and the measurement of contractile force in the trabeculae, respectively. A photomultiplier tube produced by IonOptix© will detect calcium release in the cell, allowing us to compare calcium release after infarction and following cell therapy. Observing differences in calcium release and force production between infarcted and cell-injected hearts is the next step in understanding how cell therapy improves cardiac function following infarction. No study has ever looked at how calcium handling changes after cell therapy, so the design of this device is crucial to the advancement of understanding cell therapy as a whole.

Kwang Seob Kim - Bioengineering and Biochemistry

Kwang Seob Kim in labGrowing up with parents who suffered from polio, I have always been interested in helping people with disabilities. I have struggled to find a field which I enjoyed that could train me to effectively help those who suffer from various diseases. While I received my education from the Department of Bioengineering, and worked in the Laboratory for Speech Physiology and Motor Control advised by Dr. Ludo Max, my ambitions became realized.

In Dr. Max’s lab, we attempt to better understand the central nervous system functioning in speech and non-speech movements, as well as the neural mechanisms underlying stuttering in particular. Our understanding of how the brain learns speech motor control is still limited as previous studies have mainly focused on upper limb sensorimotor control. The goal of my project is to design a protocol/procedure to quantify the ability of the speech sensorimotor systems to learn a completely novel sensorimotor mapping. This protocol has the potential to not only enhance our knowledge of motor learning, but to also improve the rehabilitation of individuals with movement disorders.

In the future, I wish to continue to research speech and/or non-speech motor control, including the development of neural prostheses (brain machine interfaces) for individuals with brain damage. Currently I am applying to various schools with doctorate programs focusing on neural engineering, motor control, and rehabilitation.

I would like to once again express my gratitude for support provided by the Washington Research Foundation Fellowship as it has allowed me to conduct my capstone project in bioengineering as well as continue to pursue my academic interests.

Mentor: Ludo Max, Speech and Hearing Sciences

Project Title: An integrated hardware-software approach to quantify the speech projection system’s ability to learn movements with novel motor-to-sensory transformations

Abstract: Scientific knowledge of the brain is still considerably limited, especially on understanding of functions such as motor learning. Although many procedures have been designed to assess an individual’s ability to update motor commands in an altered environment, few attempts have been made to design procedures to assess, and possibly improve, an individual’s ability to learn a completely novel mapping of motor commands and sensory consequences. The latter approach has clinical potential given that brain disorders cause deficits in such neural representations and alternative movement strategies may aid recovery. While the above studies focused on hand or arm movements, we are interested in the speech motor system. This project aims to design the MATLAB code and protocols to test and quantify the ability of the speech motor system to learn neural representations of a novel link between motor commands and sensory results. We will make use of 3D electromagnetic motion capture technology that can track 3 position coordinates and 2 angles for up to 9 sensors on the tongue, lips, and jaw; thus for a maximum of 45 dimensions. These 45 dimensions will be mapped onto 2-dimensional movement of a cursor on a computer monitor. As subjects are instructed to move the cursor, subjects’ performance (i.e., learning of the novel mapping) will be quantified. We will then test an individual or a group of individuals from a clinical population (such as those with motor speech disorders or stuttering) and analyze their performance over time to design the most optimal techniques and procedures for quantifying speech sensorimotor system’s ability to learn the complex relationship between a high-dimensional movement space and a 2-dimensional visual space.

Dan Minter - Neurobiology

Dan Minter sitting in labWithout doubt, the greatest decision that I made during my education was to study neurobiology. Ever since beginning this major, I have found myself absolutely gripped by fascination and interest in the complex neural structures that underlie our behavior, thoughts, and actions. Yet more that, I am extremely appreciative of the many amazing opportunities that the NBIO program has afforded to me and my classmates.

Starting in June 2010, I began to work in the laboratory of Dr. William Moody, the director and founder of the undergraduate NBIO program. As part of this experience, the other undergraduates and I were able to learn a variety of new techniques as we studied the role and nature of spontaneous waves of electrical activity in the developing cerebral cortex. Most importantly, however, we were given the freedom to explore and design our own projects while at the same time developing a close relationship with Dr. Moody.

I am currently spending this year working in the laboratory of Dr. Ana Belén Elgoyhen in Buenos Aires, Argentina. Our research is focused on the a9a10 nicotinic acetylcholine receptor, which mediates neurotransmission between the brainstem and the outer hair cells of the cochlea. In doing so, this system protects the inner ear against acoustic trauma. In my current project, I use a variety of molecular and electrophysiological techniques to study the unique pharmacological profile and structure-function relationship of this receptor.

During my time here, I have greatly furthered my understanding of neuropharmacology and receptor dynamics. Further, however, this experience has afforded me the opportunity to become immersed in another culture and broaden my understanding of the world outside of Seattle. I have little doubt that the lessons I learn this year, both science and non-science related, will greatly serve me in the future as I pursue the fields of medicine and neuroscience. In closing, I would like to sincerely thank the Washington Research Foundation, without whose generous support this experience would not have been possible.

Mentor: William Moody, Biology

Project Title: Indentification and functional characterization of the allosteric binding site for calcium ions in the a9a10 nicotinic acetylcholine receptor

Abstract: The native receptor that mediates transmission between efferent olivocochlear neurons and outer hair cells of the cochlea is composed of the α9 and α10 cholinergic nicotinic subunits. This receptor differentiates itself from other members of the nicotinic acetylcholine (ACh) receptor family in multiple ways, arguably the most notable being its distinct pharmacological profile. While there have been many identified antagonists of this receptor, very few effective agonists have been characterized. However, in light of the proposed role of the efferent olivocochlear system in protection against acoustic damage, it is highly desirable that specific, efficacious agonists of the α9α10 receptor be identified. In this study, we have used molecular modeling of the α9α10 receptor in order to design a series of ACh analogs, which we subsequently tested for action against the α9α10 receptor expressed in Xenopus laevis oocytes. Preliminary results have been extremely promising. The first generation of compounds that we tested included two members that, while displaying EC50 values orders of magnitude lower than that of ACh, managed to more efficaciously activate currents through the receptor. A second generation was subsequently developed, and one compound was identified that had an EC50 value significantly lower than that of ACh, while displaying an efficacy statistically indistinguishable from that of the native transmitter. Based on these early results, we are striving to design a series of agonists that combine the improved efficacy and affinity observed by these different lead compounds. Subsequently, we plan to investigate the specificity of our improved agonist by testing it for action in the α7 and α4β2 neuronal nicotinic ACh receptors. We hope that the work we are currently performing could someday provide the basis for the development of a novel drug that could be used in the protection against acoustic trauma.

Josh Scotland - Computer Science and Business Administration

Josh Scotland standing with laptop outsideI embarked on my journey of accessibility research three years ago, right after getting into the Computer Science department. I was lucky to have met Dr. Richard Ladner and be chosen to take lead on one of his projects. Deciding to do research was one of the best and most rewarding choices I have made.

Since then, I have been involved with several projects, studies, workshops, and outreach programs where I have gained insight into how the accessibility industry works and what needs to be improved. Upon completion of my first project, I was able to increase the usability of tactile images and successfully integrate an audio component into the automated workflow.

My passion lies in making the world a better place by pushing the limits of software. I want to thank the Washington Research Foundation for this wonderful opportunity to have a big impact on the world of computational photography for greater accessibility. I am confident my research will yield results that will help people of any kind feel less restricted by insufficient visual information.

Mentor: Richard Ladner, Computer Science & Engineering

Project Title: Computational Photography for Greater Accessibility

Abstract: Images are a powerful way to communicate, preserve, and educate. Their powerful expressiveness has led to much research over the past several decades to improve photography. The latest development is computational photography, which is an emerging field of study that uses sensory information to compute the final photo. The goal is to improve images by combining digital data with computing power to generate superior images. Techniques that represent computational photography include panoramic stitching, high-dynamic-range (HDR) imaging, and light-field imaging.

Andrew Adams, a leading Stanford researcher behind computational photography, released a fully programmable digital camera system to aid other researchers in computational photography. Named FCam, it is an open-source C++ application programmable interface (API) for easy and precise control of digital cameras. My research will focus on using the FCam API to develop faster, smarter algorithms to create images for accessibility purposes.

Computational photography can be directly applied to several accessibility research projects. Initially, I will only focus on two. The first application is for VizWiz, which is a talking mobile phone application that answers visual questions in nearly real time. The second application of my computational photography research is for MobileOCR. After taking a photo of printed text, MobileOCR reads the text aloud using an intuitive screen reader. VizWiz and MobileOCR are just two of the many accessibility applications that can benefit from computational photography.

Meghin Spencer - Astronomy and Physics

Meghin Spencer at computerThe field of astronomy has been an integral part of my life for, quite literally, as long as I can remember. Over the years, spectacles such as meteor showers, comet passings, eclipses and planet transits only heightened my excitement. Therefore, it seemed natural that I major in astronomy and physics at the University of Washington. It is here that I learned how much more there is to the study than what meets the (unaided) eye. By involving myself with an array of research projects, ranging from low mass stars to planetary nebulae to spiral galaxies, and studies of both the radio and optical regimes, I feel I have extremely broadened my undergraduate knowledge.

Though I have spent a significant amount of time exploring the different subGfields of astronomy through research and other activities, the project that I have dedicated the majority of my time to pertains to something that we can’t even see: dark matter. Discovered in 1934, its nature remains one of the most pressing scientific mysteries of the modern era, a bothersome fact considering dark matter accounts for about 85% of the total matter in the universe. My project focuses on constraining the amount of dark matter within large spiral galaxies under the guidance of Drs. Zeljko Ivezic and Peter Yoachim. While most studies rely on dynamical tracers such as neutral hydrogen gas, planetary nebulae, or globular clusters to map out the gravitational well of a galaxy, my study uses satellite galaxies. It is a relatively new technique because the amount of detected satellites around any given spiral galaxy is generally not sufficient to accurately determine its mass. However, recent searches within the SDSS database reveal that this may not be the case, especially for galaxy NGC 4258. By spectroscopically observing galaxies that could potentially be satellites with the Apache Point Observatory 3.5Gmeter telescope, I can determine whether they are in fact satellites or simply high redshift galaxies, and use those measurements to produce an estimate for the galaxy’s total mass. This research will be presented in the 219th American Astronomical Society meeting in Austin, Texas next January, and should lead to a published paper.

Next year I plan on attending graduate school so that I can obtain a Ph.D. in astronomy.

I am incredibly thankful to the Washington Research Foundation for this fellowship, without which I could not present this research to the greater astronomy society.

Mentor: Peter Yoachim, Astronomy

Project Title: Utilizing Satellite Galaxies to Understand the Nature of Dark Matter

Abstract: I propose to estimate the mass of the extended dark matter halo of nearby spiral galaxy NGC 4258 by measuring the velocity dispersion of its satellite galaxy system. This galaxy is particularly interesting because it is similar in size to the Milky Way, and has the largest amount of known satellites for any galaxy outside the Local Group. Before I began, I searched the Sloan Digital Sky Survey (SDSS) database and found 15 satellite galaxies that already have spectra. I then made a list of target satellite galaxies, 34 of which I was able to observe in 5 half-nights with the 3.5-meter APO telescope. By combining my measurements with those already taken, I can make a reasonable conclusion on the dark matter halo mass. Next, I intend to make further observations with the Wisconsin Indiana Yale and NOAO (WIYN) telescope. These additional satellite galaxies will provide me with around 40 good velocity measurements, enabling me to constrain the dark matter halo mass to within a 25% error. I will write a computer program that will be able to automatically reduce the WIYN data so that similar studies in the future can be completed with more ease. The research proposed here will be especially useful during the era of the Large Synoptic Survey Telescope (LSST) when other galaxy systems containing large amounts of satellite galaxies will become accessible to similar type studies due to the enhanced telescope magnification. This work is anticipated to yield a preliminary presentation in the January American Astronomical Society (AAS) meeting and a refereed paper in the Astrophysical Journal by the end of the next academic year.

Elizabeth Stanley - Microbiology

Elizabeth Stanley sitting in labI began working in Mark Majesky’s lab at Seattle Children’s during my sophomore year of college, and since then research has been an integral part of my studies. The Majesky lab focuses on the genetics and development of the cardiovascular system. In particular my work relates to a congenital heart defect called coarctation of the aorta, which entails a distinct narrowing of the vessel and requires surgical repair. I have been working on this particular project for just over a year now, and am excited to move beyond a preliminary stage with support from the WRF.

My experience with undergraduate research has increased the enthusiasm I already had for science, and has motivated me to move ahead with research as a career. I look forward to applying to graduate school while seeing what I can accomplish during my time in the coming year with support from the WRF.

Mentor: Mark Majesky, Pediatrics, Pathology

Project Title: Characterization of the Ductus-Aorta Boundary by Differential Expression of Chemorepulsive Ligands and Receptors

Abstract: Congenital heart defects are the most common form of birth defect, affecting about one out of every 100 newborns in the US. Ten percent of these afflicted newborns will experience a narrowing of their aorta, formally called coarctation of the aorta. Coarctation can result in extreme hypoxia in tissues that do not receive sufficient blood supply, and can eventually lead to congestive heart failure; surgical repair is required for the infant to regain normal circulation. The etiology of coarctation has been linked in many cases to migration of cells from the ductus arteriosus into the aorta. The ductus arteriosus is a fetal vessel that must close at birth, and does so by constriction of its smooth muscle cells until its lumen is occluded. If these contractile cells migrate into the aorta, they can constrict, narrowing the aortic lumen. Preliminary data from experiments on the region where the ductus inserts into the aorta show a differential expression of chemorepulsive signaling proteins from the Slit and Robo families in ductal versus aortic tissue, suggesting that a distinct tissue boundary forms in this region. This is supported by previous studies in lineage mapping, which demonstrated a distinct somite-neural crest smooth muscle lineage boundary in the aortic arch. In order to elucidate the role that Slit and Robo proteins play in determining the ductus-aorta boundary, I use reverse transcription PCR and microarray analysis to examine the expression of Slit-Robo ligand and receptor proteins in perinatal ductal and aortic tissue. By comparing expression in normal samples with samples from patients with coarctation, more insight into the influence of Slit-Robo chemorepulsive signaling on boundary formation will be gained. Characterization of the ductus-aorta boundary by identification of differential ligand-receptor expression is critical to understanding the role that abnormal boundary formation plays in coarctation of the aorta.

Anning Yao - Bioengineering

Anning Yao sitting in labThe volunteer experience I had when the miserable earthquake happened in Sichuan province, China in 2008 gave me the determination of getting into biomedical field. When I saw the survivors lost their arms and legs, I wish I could help while I had zero knowledge in medical science. That moment dawned on me that advanced technology plays a crucial part in medical care and without it, it could be detrimental. It was at that moment of fear that I decided to pursue a career in biomedical research.

I started my first research experience in Dr. Pierre Mourad’s lab at the Department of Neurosurgery, where I received intensive trainings on animal surgeries and assisted many animal-related imaging experiments. Armed with the surgical and image processing skills I gained during the summer, I moved to my first independent project, in which I optimized and tested a commercial imaging device based on ultrasound elastography to detect diaschisis of ischemic stroke, in my junior year. One of the most valuable lessons I have learned from medical research is that even if it does fail most of the time, I can never lose hope because I do not know when I will see the light in the tunnel. During the summer of 2011, I had a research internship in the Tissue Engineering Research Center, Academy of Military Medical Science in China, where I performed research on heart tissue regeneration in vitro and stem cell therapy on ischemic myocardium. In the senior year, I will take a further step towards my stroke project. I will build a research-based ultrasound-imaging device that allows complete control over all aspects including data acquisition and processing, image formation and display, and user interface.

The passion for research motivates me to pursue a Ph.D. degree after graduation, and I truthfully hope to contribute more to the field of medical imaging and tissue engineering during my career. I am really grateful for the financial support from the Washington Research Foundation Fellowship as it allows me to continue conducting my research on the stroke-imaging project and motivates me to pursue a further career in biomedical field.

Mentor: Pierre Mourad, Neurosurgery

Project Title: The Use of Ultrasound Elastography as an Imaging Tool for Stroke

Abstract:Stroke is the degeneration of brain tissue caused by blockage of blood flow to the brain. Stroke can cause permanent brain damage, complications, and death. It is one of the leading causes of adult disability and death worldwide. Ultrasound (US) elastography is a technique that measures local tissue deformation from ultrasound-induced shear wave propagation within tissue from which it derives estimates of local tissue stiffness. US elastography has been applied to differential diagnosis of breast and prostate cancers, but has not been applied to stroke, until now. The purpose of the study is to explore our hypothesis that ultrasound elastography based on exogenous brain tissue displacement is sufficient to map and quantify the tissue stiffness of brain after stroke. Our preliminary studies performed using a commercial ultrasound-imaging machine on 30 live mice with stroke induced by means of surgical occlusion of the middle cerebral artery demonstrated reduced stiffness (low shear modulus) in the hemisphere with stroke as compared with the contralateral, stroke-free hemisphere. However, imaging artifacts always appear around the skull, which distort the imaging results, such that it is hard to quantify sub-hemispheric variations in brain-tissue stiffness. We propose to optimize the research ultrasound-imaging device in order to generate quantitative elastograms without imaging artifacts. Compared with the commercial ultrasound device, the research ultrasound device allows complete control over all aspects including data acquisition, data processing, image formation, image display and user interface, which involves in optimization of all types of pre-image processing parameters. The optimized elastograms will be compared with histology images. The difference in stiffness between two hemispheres will be evaluated using statistical tests. This research will be a key step toward exploring the ultrasound parameters for imaging stroke, which will contribute to the development of a better imaging tool for potential stroke patients.