Full metadata
Title
Fast, variable system delay correction for spiral MRI
Description
Magnetic Resonance Imaging using spiral trajectories has many advantages in speed, efficiency in data-acquistion and robustness to motion and flow related artifacts. The increase in sampling speed, however, requires high performance of the gradient system. Hardware inaccuracies from system delays and eddy currents can cause spatial and temporal distortions in the encoding gradient waveforms. This causes sampling discrepancies between the actual and the ideal k-space trajectory. Reconstruction assuming an ideal trajectory can result in shading and blurring artifacts in spiral images. Current methods to estimate such hardware errors require many modifications to the pulse sequence, phantom measurements or specialized hardware. This work presents a new method to estimate time-varying system delays for spiral-based trajectories. It requires a minor modification of a conventional stack-of-spirals sequence and analyzes data collected on three orthogonal cylinders. The method is fast, robust to off-resonance effects, requires no phantom measurements or specialized hardware and estimate variable system delays for the three gradient channels over the data-sampling period. The initial results are presented for acquired phantom and in-vivo data, which show a substantial reduction in the artifacts and improvement in the image quality.
Date Created
2013
Contributors
- Bhavsar, Payal (Author)
- Pipe, James G (Thesis advisor)
- Frakes, David (Committee member)
- Kodibagkar, Vikram (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
ix, 44 p. : ill. (mostly col.)
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.20830
Statement of Responsibility
by Payal Bhavsar
Description Source
Retrieved on Feb. 19, 2014
Level of coding
full
Note
thesis
Partial requirement for: M.S., Arizona State University, 2013
bibliography
Includes bibliographical references (p. 41-44)
Field of study: Bioengineering
System Created
- 2014-01-31 11:31:18
System Modified
- 2021-08-30 01:37:42
- 3 years 2 months ago
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