The goal of this research is to develop image reconstruction techniques to automatically correct for errors in Magnetic Resonance Imaging (MRI) data due to errors in the trajectory used in the data acquisition. A method is presented to perform an iterative image reconstruction correcting for these trajectory errors in non-Cartesian acquisitions, without additional scans or measurements.
The Trajectory Auto-Corrected image Reconstruction (TrACR) method jointly estimates k-space trajectory errors and images,
based on SENSE and SPIRiT parallel imaging reconstruction.
The underlying idea is that parallel imaging and oversampling in the center of k-space provides
data redundancy that can be exploited to simultaneously reconstruct images and correct trajectory errors.
Trajectory errors are represented as weighted sums of trajectory-dependent error basis functions,
the coefficients of which are estimated using gradient-based optimization.
TrACR was applied to reconstruct images and errors in golden angle radial, center-out radial,
and spiral in vivo 7 Tesla brain acquisitions in 5 subjects.
Compared to reconstructions using nominal trajectories, TrACR reconstructions
contained considerably less blurring and streaking, and were of similar quality to
images reconstructed using measured k-space trajectories in the center-out radial and spiral cases.
Reconstruction cost function reductions and improvements in normalized image gradient squared
were also similar to those for images reconstructed using measured trajectories.
TrACR enables non-Cartesian image reconstructions free from trajectory errors without the need for separate gradient calibrations or trajectory measurements.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-11202015-114621 |
| Date | 20 November 2015 |
| Creators | Ianni, Julianna Denise |
| Contributors | Adam W. Anderson, William A. Grissom |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-11202015-114621/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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