Model-based artifact correction in MRI
Abstract/Contents
- Abstract
- Magnetic Resonance Imaging (MRI) is an imaging modality known for its safety and excellent soft tissue contrast. It is estimated that two out of every hundred Americans have an artificial hip or knee. MRI can serve as a useful tool for postsurgical examination of joint replacement surgeries. However, current techniques that remove image distortion near metallic implants struggle near the metal and also blur the images, potentially making diagnosis harder for radiologists. In this work we present an approach to deblur MRI images near metallic implants. This method consists of improved field-map estimation and spectral bin combination techniques. We also introduce a method to find a good balance between blurring and distortion in regions where the field-map estimation is unreliable. This method is compared in phantoms and in vivo and shown to perform substantially better than current approaches. Additionally, due to its superb soft-tissue contrast, MRI also excels at diagnosis of lesions and cysts. These tissues are often easier to visualize and diagnose when signal from fat, which is often bright in MRI images, is suppressed or separated from that of other "water" tissues. Current techniques for suppressing or separating fat are often unable to do so throughout the entire image and/or lead to long acquisition times. In this work we first present an approach that enables the separation of fat and water while enabling high-resolution imaging and T2-like contrast in short scan times. This approach uses improved signal modeling to enable improved fat/water separation iv using an SNR-efficient balanced Steady-State Free-Precession (bSSFP) two-point Dixon method, while simultaneously reducing the banding artifacts associated with bSSFP sequences. Furthermore, an analysis to assess the viability of a method that combines two-point Dixon fat/water separation with the time-saving benefits of Homodyne reconstructions is also performed. This analysis finds that while the described approach could save time, it's clinical usability may be limited due to artifacts created at fat/water tissue interfaces.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Quist, Brady |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering. |
| Primary advisor | Hargreaves, Brian Andrew |
| Thesis advisor | Hargreaves, Brian Andrew |
| Thesis advisor | Daniel, Bruce (Bruce Lewis) |
| Thesis advisor | Nishimura, Dwight George |
| Advisor | Daniel, Bruce (Bruce Lewis) |
| Advisor | Nishimura, Dwight George |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Brady Quist. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Brady Jon Quist
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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