Matching Items (5)
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- All Subjects: Hypoxia
- Creators: Kodibagkar, Vikram
- Creators: Beeman, Scott
Description
The objective of the research presented here was to validate the use of kinetic models for the analysis of the dynamic behavior of a contrast agent in tumor tissue and evaluate the utility of such models in determining kinetic properties - in particular perfusion and molecular binding uptake associated with tissue hypoxia - of the imaged tissue, from concentration data acquired with dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) procedure. Data from two separate DCE-MRI experiments, performed in the past, using a standard contrast agent and a hypoxia-binding agent respectively, were analyzed. The results of the analysis demonstrated that the models used may provide novel characterization of the tumor tissue properties. Future research will work to further characterize the physical significance of the estimated parameters, particularly to provide quantitative oxygenation data for the imaged tissue.
ContributorsMartin, Jonathan Michael (Author) / Kodibagkar, Vikram (Thesis director) / Rege, Kaushal (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2013-12
Description
Oxygen delivery is crucial for the development of healthy, functional tissue. Low tissue oxygenation, or hypoxia, is a characteristic that is common in many tumors. Hypoxia contributes to tumor malignancy and can reduce the success of chemotherapy and radiation treatment. There is a current need to noninvasively measure tumor oxygenation or pO2 in patients to determine a personalized treatment method. This project focuses on creating and characterizing nanoemulsions using a pO2 reporter molecule hexamethyldisiloxane (HMDSO) and its longer chain variants as well as assessing their cytotoxicity. We also explored creating multi-modal (MRI/Fluorescence) nanoemulsions.
ContributorsGrucky, Marian Louise (Author) / Kodibagkar, Vikram (Thesis director) / Rege, Kaushal (Committee member) / Stabenfeldt, Sarah (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2013-05
Description
Magnetic resonance imaging (MRI) of changes in metabolic activity in tumors and metabolic abnormalities can provide a window to understanding the complex behavior of malignant tumors. Both diagnostics and treatment options can be improved through the further comprehension of the processes that contribute to tumor malignancy and growth. By detecting and disturbing this activity through personalized treatments, it is the hope to provide better diagnostics and care to patients. Experimenting with multicellular tumor spheroids (MCTS) allows for a rapid, inexpensive and convenient solution to studying multiple in vitro tumors. High quality magnetic resonance images of small samples, such as spheroid, however, are difficult to achieve with current radio frequency coils. In addition, in order for the information provided by these scans to accurately represent the interactions and metabolic activity in vivo, there is a need for a perfused vascular network. A perfused vascular network has the potential to improve metabolic realism and particle transport within a tumor spheroid. By creating a more life-like cancer model and allowing the progressive imaging of metabolic functions of such small samples, a better, more efficient mode of studying metabolic activity in cancer can be created and research efforts can expand. The progress described in this paper attempts to address both of these current shortcomings of metabolic cancer research and offers potential solutions, while acknowledging the potential of future work to improve cancer research with MCTS.
ContributorsTobey, John Paul (Author) / Kodibagkar, Vikram (Thesis director) / Sadleir, Rosalind (Committee member) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Compressed sensing magnetic resonance spectroscopic imaging (MRSI) is a noninvasive and in vivo potential diagnostic technique for cancer imaging. This technique undersamples the distribution of specific cancer biomarkers within an MR image as well as changes in the temporal dimension and subsequently reconstructs the missing data. This technique has been shown to retain a high level of fidelity even with an acceleration factor of 5. Currently there exist several different scanner types that each have their separate analytical methods in MATLAB. A graphical user interface (GUI) was created to facilitate a single computing platform for these different scanner types in order to improve the ease and efficiency with which researchers and clinicians interact with this technique. A GUI was successfully created for both prospective and retrospective MRSI data analysis. This GUI retained the original high fidelity of the reconstruction technique and gave the user the ability to load data, load reference images, display intensity maps, display spectra mosaics, generate a mask, display the mask, display kspace and save the corresponding spectra, reconstruction, and mask files. Parallelization of the reconstruction algorithm was explored but implementation was ultimately unsuccessful. Future work could consist of integrating this parallelization method, adding intensity overlay functionality and improving aesthetics.
ContributorsLammers, Luke Michael (Author) / Kodibagkar, Vikram (Thesis director) / Hu, Harry (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Magnetic resonance imaging (MRI) is a noninvasive imaging modality, which is used for many different applications. The versatility of MRI is in acquiring high resolution anatomical and functional images with no use of ionizing radiation. The contrast in MR images can be engineered by two different mechanisms with imaging parameters (TR, TE, α) and/or contrast agents. The contrast in the former is influenced by the intrinsic properties of the tissue (T1, T2, ρ), while the contrast agents change the relaxation rate of the protons to enhance contrast. Contrast agents have attracted a lot of attention because they can be modified with targeting groups to shed light on some physiological and biological questions, such as the presence of hypoxia in a tissue. Hypoxia, defined as lack of oxygen, has many known ramifications on the outcome of therapy in any condition. Hence its study is very important. The standard gold method to detect hypoxia, immunohistochemical (IHC) staining of pimonidazole, is invasive; however, there are many research groups focused on developing new and mainly noninvasive methods to investigate hypoxia in different tissues.Previously, a novel nitroimidazole-based T1 contrast agent, gadolinium tetraazacyclododecanetetraacetic acid monoamide conjugate of 2-nitroimidazole (GdDO3NI ), has been synthesized and characterized on subcutaneous prostate and lung tumor models. Here, its efficacy and performance on traumatic brain injuries and brain tumors are studied. The pharmacokinetic properties of the contrast agent the perfusion properties of brain tumors are investigated. These results can be used in personalized therapies for more effective results for patients.
Gadolinium (Gd), which is a strongly paramagnetic heavy metal, is routinely and widely used as an MR contrast agent by chelation with a biocompatible ligand which is typically cleared through the kidneys. While widely used, there are serious concerns for patients with impaired kidney function, as well as recent studies showed Gd accumulation in the bone and brain. Iron as a physiological ion is also capable of generating contrast in MR images. Here synthesis and characterization of an iron-based hypoxia targeting contrast agent is proposed to eliminate Gd-related complications and provide a cheaper and more economical alternative contrast agent to detect hypoxia.
ContributorsMoghadas, Babak (Author) / Kodibagkar, Vikram D (Thesis advisor) / Beeman, Scott (Committee member) / Muthuswamy, Jitendran (Committee member) / Nikkhah, Mehdi (Committee member) / Turner, Gregory (Committee member) / Arizona State University (Publisher)
Created2021