Robust body diffusion-weighted magnetic resonance imaging
Abstract/Contents
- Abstract
- Body MRI has progressed as a detection method for many pathologic processes. It is effective in helping in the diagnosis of unknown primary malignancy, determining the skeletal spread of metastasis, and as a cancer screening and staging tool. Diffusion-weighted imaging (DWI) is an MRI sequence that relies on alteration in intra- and extracellular water content from the transmembrane water flux to generate image contrast. DWI is routinely used in brain imaging and is particularly useful for early detection of ischemia. However, extending DWI to body MRI poses additional technical challenges such as organ movement, proximity to gasses in bowels and lungs, and greater variability of tissue body water composition. Despite these challenges and associated image artifacts, DWI is used in many clinical scanning protocols. However, due to image artifacts and loss of image integrity and quality, the efficacy of using these images in a clinical setting is diminished. This thesis focuses on developing a DWI sequence for body MRI that is tailored to overcoming these technical challenges. Specifically, this work comprises of combining diffusion contrast preparation with a single-shot fast spin echo (SS-FSE) imaging pulse sequence. Despite its promised robustness, the SS-FSE sequence is subject to various constraints on signal phase, which cannot be guaranteed in the presence of diffusion weighting. This work overcomes this by using two approaches. The first approach uses a quadratic phase modulation throughout the echo train. This work improves this sequence by 1) redesigning the acquisition sampling pattern and reconstruction and 2) enhancing the signal stability in this sequence through optimizing the RF pulses used in the echo train. This sequence is rigorously validated in simulation, phantom scans, and clinical in vivo patient scans at the Lucille Packard Children's Hospital. The second approach consists of using a different SS-FSE sequence but is able to design the diffusion preparation module such that the unstable portion of the signal is eliminated prior to imaging. This sequence is also rigorously validated in simulation, in phantom scans, and in patient scans.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2017 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Gibbons, Eric Kenneth |
|---|---|
| Associated with | Stanford University, Department of Bioengineering. |
| Primary advisor | Pauly, John (John M.) |
| Thesis advisor | Pauly, John (John M.) |
| Thesis advisor | Nishimura, Dwight George |
| Thesis advisor | Pelc, Norbert J |
| Advisor | Nishimura, Dwight George |
| Advisor | Pelc, Norbert J |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Eric Kenneth Gibbons. |
|---|---|
| Note | Submitted to the Department of Bioengineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2017. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2017 by Eric Kenneth Gibbons
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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