Dissertation
Understanding the factors contributing to T1rho relaxation
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Summer 2021
DOI: 10.17077/etd.005919
Abstract
The prevalence of neurological and psychiatric disorders has led to an increase in attention from the clinical and research community in recent years. In the United States, Alzheimer’s Disease is the most common neurological disorder, with approximately 5.4 million sufferers over the age of 65 in 2020. Whereas in psychiatric disorders, Bipolar Disorder sufferers are ranked as exhibiting the most severe impairment among mood disorders though representing only 2.8% of the population in a 2007 study. Pathophysiology of these disorders have been characterized by abnormal metabolism, whereby the agglomeration of proteins leads to the progression of symptoms. Additionally, in some cases, local acidosis in affected brain regions has been found to contribute to disease progression. Being able to assess brain function by way of abnormal metabolism would aid in understanding more about disease progression and diagnosis of such disorders.The longitudinal magnetization relaxation time in the rotating frame (T1rho) is a form of contrast in magnetic resonance imaging (MRI) that can be used to assess changes in metabolism. It is sensitive to changes in pH and macromolecular composition and can thus be used to assess environments where these things are in flux. T1rho values are dependent also on static magnetic and radiofrequency field strengths. Thus, in this work, the sensitivity of T1rho to pH and macromolecular composition is assessed at 3 Tesla (3T) field strength and pH solely at 7T. At 3T a test object (phantom) is imaged that allows for varied concentrations of acid, metabolites such as glucose and lysine. An in vivo study is undertaken at 7T in a mouse model where local acidosis is induced by optical stimulation of the somatosensory cortex.
Details
- Title: Subtitle
- Understanding the factors contributing to T1rho relaxation
- Creators
- Nana K. Owusu
- Contributors
- Vincent A. Magnotta (Advisor)Joseph M. Reinhardt (Committee Member)Daniel R. Thedens (Committee Member)Mathews Jacob (Committee Member)Sajan G. Lingala (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Biomedical Engineering
- Date degree season
- Summer 2021
- DOI
- 10.17077/etd.005919
- Publisher
- University of Iowa
- Number of pages
- ix, 61 pages
- Copyright
- Copyright 2021 Nana Kwame Owusu
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 52-61).
- Public Abstract (ETD)
There are many in the United States who suffer from psychiatric disorders as well as age-related and hereditary brain disorders. In the year 2020, the number of elderly Americans over the age of 65 diagnosed with Alzheimer’s Disease was over 5 million, making it the most common age-related brain disease. Bipolar Disorder, in a 2007 survey of psychiatric disorders was found to affect 2.8% of the population. Brain disorders like Alzheimer’s, share a characteristic representing inefficiency in cleaning-up waste from energy consumption. With the inefficient clean-up comes a build-up of a specific protein, as well as the mismanagement of local acid concentration. Psychiatric disorders also have this mismanagement of local acid concentration. If the changes in acidity occurring in the brains of those with said brain and psychiatric disorders could be used as a way of assessing brain function, that would be a way to study the way those disorders progress.
In the imaging sciences, there are ways to capture images of the functioning brain using changes in the chemical environment. The work presented here was conducted using large, powerful magnets to collect images; a technique was employed that is sensitive to the changes in chemical environments. To understand more the output of the technique in living things, test objects and mice were imaged in controlled environments at different magnetic strengths.
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering
- Record Identifier
- 9984124759502771
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