Matching Items (13)
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- All Subjects: Biomedical
- All Subjects: MRI
- Creators: Harrington Bioengineering Program
- Resource Type: Text
Description
Glioblastoma multiforme (GBM) is a malignant, aggressive and infiltrative cancer of the central nervous system with a median survival of 14.6 months with standard care. Diagnosis of GBM is made using medical imaging such as magnetic resonance imaging (MRI) or computed tomography (CT). Treatment is informed by medical images and includes chemotherapy, radiation therapy, and surgical removal if the tumor is surgically accessible. Treatment seldom results in a significant increase in longevity, partly due to the lack of precise information regarding tumor size and location. This lack of information arises from the physical limitations of MR and CT imaging coupled with the diffusive nature of glioblastoma tumors. GBM tumor cells can migrate far beyond the visible boundaries of the tumor and will result in a recurring tumor if not killed or removed. Since medical images are the only readily available information about the tumor, we aim to improve mathematical models of tumor growth to better estimate the missing information. Particularly, we investigate the effect of random variation in tumor cell behavior (anisotropy) using stochastic parameterizations of an established proliferation-diffusion model of tumor growth. To evaluate the performance of our mathematical model, we use MR images from an animal model consisting of Murine GL261 tumors implanted in immunocompetent mice, which provides consistency in tumor initiation and location, immune response, genetic variation, and treatment. Compared to non-stochastic simulations, stochastic simulations showed improved volume accuracy when proliferation variability was high, but diffusion variability was found to only marginally affect tumor volume estimates. Neither proliferation nor diffusion variability significantly affected the spatial distribution accuracy of the simulations. While certain cases of stochastic parameterizations improved volume accuracy, they failed to significantly improve simulation accuracy overall. Both the non-stochastic and stochastic simulations failed to achieve over 75% spatial distribution accuracy, suggesting that the underlying structure of the model fails to capture one or more biological processes that affect tumor growth. Two biological features that are candidates for further investigation are angiogenesis and anisotropy resulting from differences between white and gray matter. Time-dependent proliferation and diffusion terms could be introduced to model angiogenesis, and diffusion weighed imaging (DTI) could be used to differentiate between white and gray matter, which might allow for improved estimates brain anisotropy.
ContributorsAnderies, Barrett James (Author) / Kostelich, Eric (Thesis director) / Kuang, Yang (Committee member) / Stepien, Tracy (Committee member) / Harrington Bioengineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Spasticity is a neurological disorder in which a target group of muscles remain in a contracted state. In addition to interfering with the function of these muscles, spasticity causes chronic pain and discomfort. Often found in patients with cerebral palsy, multiple sclerosis, or stroke history, spasticity affects an estimated twelve million people worldwide. Not only does spasticity cause discomfort and loss of function, but the condition can lead to contractures, or permanent shortenings of the muscle and connective tissue, if left untreated. Current treatments for spasticity are primarily different forms of muscle relaxant pharmaceuticals. Almost all of these drugs, however, carry unwanted side effects, including total muscle weakness, liver toxicity, and possible dependence. Additionally, kinesiotherapy, conducted by physical therapists at rehabilitation clinics, is often prescribed to people suffering from spasticity. Since kinesiotherapy requires frequent practice to be effective, proper treatment requires constant professional care and clinic appointments, discouraging patient compliance. Consequently, a medical device that could automate relief for spasticity outside of a clinic is desired in the market. While a number of different dynamic splints for hand spasticity are currently on the market, research has shown that these devices, which simply brace the hand in an extended position, do not work through any mechanism to decrease spastic tension over time. Two methods of temporarily reducing spasticity that have been observed in clinical studies are cryotherapy, or the decrease of temperature on a target area, and electrotherapy, which is the delivery of regulated electrical pulses to a target area. It is possible that either of these mechanisms could be incorporated into a medical device aimed toward spastic relief. In fact, electrotherapy is used in a current market device called the SaeboStim, which is advertised to help stroke recovery and spastic reduction. The purpose of this paper is to evaluate the viability of a potential spastic relief device that utilizes cryotherapy to a current and closest competitor, the SaeboStim. The effectiveness of each device in relieving spasticity is reviewed. The two devices are also compared on their ability to address primary customer needs, such as convenience, ease of use, durability, and price. Overall, it is concluded that the cryotherapy device more effectively relieves hand spasticity in users, although the SaeboStim's smaller size and better convenience gives it market appeal, and reveals some of the shortcomings in the preliminary design of the cryotherapy device.
ContributorsWiedeman, Christopher Blaise (Author) / Kleim, Jeffrey (Thesis director) / Buneo, Christopher (Committee member) / W.P. Carey School of Business (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Smart contrast agents allow for noninvasive study of specific events or tissue conditions inside of a patient's body using Magnetic Resonance Imaging (MRI). This research aims to develop and characterize novel smart contrast agents for MRI that respond to temperature changes in tissue microenvironments. Transmission Electron Microscopy, Nuclear Magnetic Resonance, and cell culture growth assays were used to characterize the physical, magnetic, and cytotoxic properties of candidate nanoprobes. The nanoprobes displayed thermosensitve MR properties with decreasing relaxivity with temperature. Future work will be focused on generating and characterizing photo-active analogues of the nanoprobes that could be used for both treatment of tissues and assessment of therapy.
ContributorsHussain, Khateeb Hyder (Author) / Kodibagkar, Vikram (Thesis director) / Stabenfeldt, Sarah (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2014-05
Description
Glioblastoma Multiforme (GBM) is an aggressive and deadly form of brain cancer with a median survival time of about a year with treatment. Due to the aggressive nature of these tumors and the tendency of gliomas to follow white matter tracks in the brain, each tumor mass has a unique growth pattern. Consequently it is difficult for neurosurgeons to anticipate where the tumor will spread in the brain, making treatment planning difficult. Archival patient data including MRI scans depicting the progress of tumors have been helpful in developing a model to predict Glioblastoma proliferation, but limited scans per patient make the tumor growth rate difficult to determine. Furthermore, patient treatment between scan points can significantly compound the challenge of accurately predicting the tumor growth. A partnership with Barrow Neurological Institute has allowed murine studies to be conducted in order to closely observe tumor growth and potentially improve the current model to more closely resemble intermittent stages of GBM growth without treatment effects.
ContributorsSnyder, Lena Haley (Author) / Kostelich, Eric (Thesis director) / Frakes, David (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
As the rates of anxiety in adults rapidly swell, new and creative treatment methods become increasingly relevant. Individuals with an anxiety disorder may experience challenging symptoms that interfere with daily activities and impede academic and social success. The purpose of this project is to design and engineer a portable heart rate monitor that communicates with an iOS mobile application for use by individuals suffering from anxiety or panic disorders. The proposed device captures the innovation of combining biosensor feedback with new, creative therapy methods on a convenient iOS application. The device is implemented as an Arduino Uno which translates radial pulse information onto an LCD screen from a wristband. Additionally, the iOS portion uses a slow expanding and collapsing animation to guide the user through a calming breathing exercise while displaying their pulse in beats per minute. The user's awareness or his or her ability to control one's own physiological state supports and facilitates an additional form of innovative therapy. The current design of the iOS app uses a random-number generator between 40 to 125 to imitate a realistic heart rate. If the value is less than 60 or greater than 105, the number is printed in red; otherwise the heart rate is displayed in green. Future versions of this device incorporate bluetooth capabilities and potentially additional synchronous methods of therapy. The information presented in this research provides an excellent example of the integrations of new mobile technology and healthcare.
ContributorsTadayon, Ramesh (Author) / Muthuswamy, Jit (Thesis director) / Towe, Bruce (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Engineers have a strong influence on everyday lives, ranging from electronics and trains to chemicals and organs [1]. However, in the United States, there is a large knowledge gap in the roles of engineers, especially in K-12 students [2] [3]. The National Academy of Engineering (NAE) recognizes the current problems in engineering, such as the dominance of white males in the field and the amount of education needed to become a successful engineer [4]. Therefore, the NAE encourages that the current engineering community begin to expose the younger generations to the real foundation of engineering: problem-solving [4]. The objective of this thesis is to minimize the knowledge gap by assessing the current perception of engineering amongst middle school and high school students and improving it through engaging and interactive presentations and activities that build upon the students’ problem-solving abilities.
The project was aimed towards middle school and high school students, as this is the estimated level where they learn biology and chemistry—key subject material in biomedical engineering. The high school students were given presentations and activities related to biomedical engineering. Additionally, within classrooms, posters were presented to middle school students. The content of the posters were students of the biomedical engineering program at ASU, coming from different ethnic backgrounds to try and evoke within the middle school students a sense of their own identity as a biomedical engineer. To evaluate the impact these materials had on the students, a survey was distributed before the students’ exposure to the materials and after that assesses the students’ understanding of engineering at two different time points. A statistical analysis was conducted with Microsoft Excel to assess the influence of the activity and/or presentation on the students’ understanding of engineering.
The project was aimed towards middle school and high school students, as this is the estimated level where they learn biology and chemistry—key subject material in biomedical engineering. The high school students were given presentations and activities related to biomedical engineering. Additionally, within classrooms, posters were presented to middle school students. The content of the posters were students of the biomedical engineering program at ASU, coming from different ethnic backgrounds to try and evoke within the middle school students a sense of their own identity as a biomedical engineer. To evaluate the impact these materials had on the students, a survey was distributed before the students’ exposure to the materials and after that assesses the students’ understanding of engineering at two different time points. A statistical analysis was conducted with Microsoft Excel to assess the influence of the activity and/or presentation on the students’ understanding of engineering.
ContributorsLlave, Alison Rose (Author) / Ganesh, Tirupalavanam (Thesis director) / Parker, Hope (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
In epilepsy, malformations that cause seizures often require surgery. The purpose of this research is to join forces with the Multi-Center Epilepsy Lesion Detection (MELD) project at University College London (UCL) in order to improve the process of detecting lesions in patients with drug-resistant epilepsy. This, in turn, will improve surgical outcomes via more structured surgical planning. It is a global effort, with more than 20 sites across 5 continents. The targeted populations for this study include patients whose epilepsy stems from Focal Cortical Dysplasia. Focal Cortical Dysplasia is an abnormality of cortical development, and causes most of the drug-resistant epilepsy. Currently, the creators of MELD have developed a set of protocols which wrap various
commands designed to streamline post-processing of MRI images. Using this partnership, the Applied Neuroscience and Technology Lab at PCH has been able to complete production of a post-processing pipeline which integrates locally sourced smoothing techniques to help identify lesions in patients with evidence of Focal Cortical Dysplasia. The end result is a system in which a patient with epilepsy may experience more successful post-surgical results due to the
combination of a lesion detection mechanism and the radiologist using their trained eye in the presurgical stages. As one of the main points of this work is the global aspect of it, Barrett thesis funding was dedicated for a trip to London in order to network with other MELD project collaborators. This was a successful trip for the project as a whole in addition to this particular thesis. The ability to troubleshoot problems with one another in a room full of subject matter
experts allowed for a high level of discussion and learning. Future work includes implementing machine learning approaches which consider all morphometry parameters simultaneously.
commands designed to streamline post-processing of MRI images. Using this partnership, the Applied Neuroscience and Technology Lab at PCH has been able to complete production of a post-processing pipeline which integrates locally sourced smoothing techniques to help identify lesions in patients with evidence of Focal Cortical Dysplasia. The end result is a system in which a patient with epilepsy may experience more successful post-surgical results due to the
combination of a lesion detection mechanism and the radiologist using their trained eye in the presurgical stages. As one of the main points of this work is the global aspect of it, Barrett thesis funding was dedicated for a trip to London in order to network with other MELD project collaborators. This was a successful trip for the project as a whole in addition to this particular thesis. The ability to troubleshoot problems with one another in a room full of subject matter
experts allowed for a high level of discussion and learning. Future work includes implementing machine learning approaches which consider all morphometry parameters simultaneously.
ContributorsHumphreys, Zachary William (Author) / Kodibagkar, Vikram (Thesis director) / Foldes, Stephen (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The International Dyslexia Association defines dyslexia as a learning disorder that is characterized by poor spelling, decoding, and word recognition abilities. There is still no known cause of dyslexia, although it is a very common disability that affects 1 in 10 people. Previous fMRI and MRI research in dyslexia has explored the neural correlations of hemispheric lateralization and phonemic awareness in dyslexia. The present study investigated the underlying neurobiology of five adults with dyslexia compared to age- and sex-matched control subjects using structural and functional magnetic resonance imaging. All subjects completed a large battery of behavioral tasks as part of a larger study and underwent functional and structural MRI acquisition. This data was collected and preprocessed at the University of Washington. Analyses focused on examining the neural correlates of hemispheric lateralization, letter reversal mistakes, reduced processing speed, and phonemic awareness. There were no significant findings of hemispheric differences between subjects with dyslexia and controls. The subject making the largest amount of letter reversal errors had deactivation in their cerebellum during the fMRI language task. Cerebellar white matter volume and surface area of the premotor cortex was the largest in the individual with the slowest reaction time to tapping. Phonemic decoding efficiency had a high correlation with neural activation in the primary motor cortex during the fMRI motor task (r=0.6). Findings from the present study suggest that brain regions utilized during motor control, such as the cerebellum, premotor cortex, and primary motor cortex, may have a larger role in dyslexia then previously considered. Future studies are needed to further distinguish the role of the cerebellum and other motor regions in relation to motor control and language processing deficits related to dyslexia.
ContributorsHoulihan, Chloe Carissa Prince (Author) / Rogalsky, Corianne (Thesis director) / Peter, Beate (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
With dwindling water resources due to drought and other pressures, water utilities are seeking to tap into alternative water sources as a means to improve water sustainability. Reclaimed water consists of treated wastewater and is widely used for non-potable purposes, such as irrigation, both agricultural and recreational. However, the reclaimed water distribution system can be subject to substantial regrowth of microorganisms, including opportunistic pathogens, even following rigorous disinfection. Factors that can influence regrowth include temperature, organic carbon levels, disinfectant type, and the time transported (i.e., water age) in the system. One opportunistic pathogen (OP) that is critical to understanding microbial activity in both reclaimed and drinking water distribution systems is Acanthamoeba. In order to better understand the potential for this amoeba to proliferate in reclaimed water systems and influence other OPs, a simulated reclaimed water distribution system was studied. The objective of this study was to compare the prevalence of Acanthamoeba and one of its endosymbionts, Legionella, across varying assimilable organic carbon (AOC) levels, temperatures, disinfectants, and water ages in a simulated reclaimed water distribution system. The results of the study showed that cooler temperatures, larger water age, and chlorine conditions yielded the lowest detection of Acanthamoeba gene copies per mL or cm2 for bulk water and biofilm samples, respectively.
ContributorsDonaldson, Kandace (Author) / Ankeny, Casey (Thesis director) / Edwards, Marc (Committee member) / Pruden, Amy (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
NIPAAm co-DEAEMA hydrogels are a potential solution for sustained, local delivery of ketorolac tromethamine. Current methods of postoperative pain management, such as local anesthetics, NSAIDs, and opioids, can be improved by minimizing side effects while still effectively treating severe and extreme pain. Though high doses of ketorolac can be toxic, sustained, local delivery via hydrogels offers a promising solution. Four ketorolac release studies were conducted using PNDJ hydrogels formulated by Sonoran Biosciences. The first two studies tested a range of JAAm concentration between 1.4 and 2.2 mole percent. Both had high initial release rates lasting less than 7 days and appeared to be unaffected by JAAm content. Tobramycin slowed down the release of ketorolac but was unable to sustain release for more than 6 days. Incorporating DEAEMA prolonged the release of ketorolac for up to 14 days with significant reductions in initial burst release rate. Low LCST of NIPAAM co-DEAEMA polymer is problematic for even drug distribution and future in vivo applications.
ContributorsHui, Nathan (Author) / Vernon, Brent (Thesis director) / Heffernan, John (Committee member) / School of International Letters and Cultures (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05