Determining optimum imaging parameters for SWIFT: application to superparamagnetic iron oxides and magnetized objects.

O’Connell, Robert Daniel
2011-06
Thumbnail Image

View/Download File

OConnell_umn_0130E_12018.pdf (2.02 MB)

Persistent link to this item

https://hdl.handle.net/11299/109822
Statistics
View Statistics

Journal Title

Journal ISSN

Volume Title

Title

Determining optimum imaging parameters for SWIFT: application to superparamagnetic iron oxides and magnetized objects.

Authors

Published Date

2011-06

Publisher

Type

Thesis or Dissertation

Abstract

A relatively new pulse sequence in MRI known as SWIFT, sweep imaging with Fourier transformation, has been shown to effectively image spins with both short and long transverse and longitudinal relaxation rates. It is desirable to have equations that accurately describe the signal of spins when excited by SWIFT; however the Bloch equations are not easily solvable for the SWIFT sequence for all relaxation rates and flip angles. The purpose of this work is to determine a set of optimization equations for the SWIFT sequence through comparison to the Ernst energy equations via a Bloch simulator. An innovative contrast technique is also developed. The optimization equations are then tested experimentally and applied to imaging of superparamagnetic iron oxides. Susceptibility artifacts distort images around metal objects. In SWIFT images the susceptibility artifacts manifest as signal voids surrounded by pileup artifacts. This work develops predictive equations for the pileup artifacts around metallic spheres. A technique called ROC, radial off-resonance correction, is developed to reconstruct distorted images by utilizing the pileup predictive equations in post-processing.

Keywords

Description

University of Minnesota Ph.D. dissertation. June 2011. Major: Physics. Advisor: Michael Garwood, PhD., 1 computer file (PDF); vi, 61 pages.

Related to

Replaces

License

Collections

Dissertations

Series/Report Number

Funding information

Isbn identifier

Doi identifier

Previously Published Citation

Suggested citation

O’Connell, Robert Daniel. (2011). Determining optimum imaging parameters for SWIFT: application to superparamagnetic iron oxides and magnetized objects.. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/109822.

Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.