Integral Equation-Based Inverse Scattering and Coil Optimization in Magnetic Resonance Imaging

One trend in Magnetic Resonance Imaging (MRI) over the years has been to steadily increase the static magnetic field strength and hence the frequency of operation, resulting in higher available signal-to-noise ratio that could be traded for shorter scan times and increased image quality. In the ultr...

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主要作者: Cruz Serrallés, José Enrique
其他作者: Daniel, Luca
格式: Thesis
出版: Massachusetts Institute of Technology 2023
在線閱讀:https://hdl.handle.net/1721.1/152694
https://orcid.org/0000-0002-3323-5688
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author Cruz Serrallés, José Enrique
author2 Daniel, Luca
author_facet Daniel, Luca
Cruz Serrallés, José Enrique
author_sort Cruz Serrallés, José Enrique
collection MIT
description One trend in Magnetic Resonance Imaging (MRI) over the years has been to steadily increase the static magnetic field strength and hence the frequency of operation, resulting in higher available signal-to-noise ratio that could be traded for shorter scan times and increased image quality. In the ultra-high field regime (≥7T), since the radiofrequency wavelength is comparable to the dimensions of body, quasi-static approaches cannot be used to simulate the interactions between electromagnetic field and biological tissue, which can result in unwanted energy deposition hot spots and in decreased image quality. The electrical properties of tissue (permittivity and conductivity) influence these interactions and the RF field distributions inside of the body. Although undesirable from the point of view of coil and pulse design, this dependence on EP opens the door to new imaging modalities using the same MR data. In this thesis, I detail how we applied highly accurate integral equation formulations to the tasks of 3D electrical properties estimation (inverse scattering) and parallel transmit (pTx) coil array optimization. I also present novel regularization strategies that are ideally suited for inverse problems. I also discuss how we validated these approaches with numerical examples, and the efforts that we undertook to estimate electrical properties of a phantom using data from an MR scanner.
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spelling mit-1721.1/1526942023-11-03T04:06:53Z Integral Equation-Based Inverse Scattering and Coil Optimization in Magnetic Resonance Imaging Cruz Serrallés, José Enrique Daniel, Luca Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science One trend in Magnetic Resonance Imaging (MRI) over the years has been to steadily increase the static magnetic field strength and hence the frequency of operation, resulting in higher available signal-to-noise ratio that could be traded for shorter scan times and increased image quality. In the ultra-high field regime (≥7T), since the radiofrequency wavelength is comparable to the dimensions of body, quasi-static approaches cannot be used to simulate the interactions between electromagnetic field and biological tissue, which can result in unwanted energy deposition hot spots and in decreased image quality. The electrical properties of tissue (permittivity and conductivity) influence these interactions and the RF field distributions inside of the body. Although undesirable from the point of view of coil and pulse design, this dependence on EP opens the door to new imaging modalities using the same MR data. In this thesis, I detail how we applied highly accurate integral equation formulations to the tasks of 3D electrical properties estimation (inverse scattering) and parallel transmit (pTx) coil array optimization. I also present novel regularization strategies that are ideally suited for inverse problems. I also discuss how we validated these approaches with numerical examples, and the efforts that we undertook to estimate electrical properties of a phantom using data from an MR scanner. Ph.D. 2023-11-02T20:09:00Z 2023-11-02T20:09:00Z 2023-09 2023-09-21T14:26:40.576Z Thesis https://hdl.handle.net/1721.1/152694 https://orcid.org/0000-0002-3323-5688 In Copyright - Educational Use Permitted Copyright retained by author(s) https://rightsstatements.org/page/InC-EDU/1.0/ application/pdf Massachusetts Institute of Technology
spellingShingle Cruz Serrallés, José Enrique
Integral Equation-Based Inverse Scattering and Coil Optimization in Magnetic Resonance Imaging
title Integral Equation-Based Inverse Scattering and Coil Optimization in Magnetic Resonance Imaging
title_full Integral Equation-Based Inverse Scattering and Coil Optimization in Magnetic Resonance Imaging
title_fullStr Integral Equation-Based Inverse Scattering and Coil Optimization in Magnetic Resonance Imaging
title_full_unstemmed Integral Equation-Based Inverse Scattering and Coil Optimization in Magnetic Resonance Imaging
title_short Integral Equation-Based Inverse Scattering and Coil Optimization in Magnetic Resonance Imaging
title_sort integral equation based inverse scattering and coil optimization in magnetic resonance imaging
url https://hdl.handle.net/1721.1/152694
https://orcid.org/0000-0002-3323-5688
work_keys_str_mv AT cruzserrallesjoseenrique integralequationbasedinversescatteringandcoiloptimizationinmagneticresonanceimaging