A fast approach to reconstruct transmit RF field (|B1+|) maps in high field parallel Magnetic Resonance Imaging is presented in this thesis. First the concepts of parallel imaging reconstruction and the Bloch-Siegert (BS) |B1+| mapping method are introduced. Then we present the idea to accelerate BS field mapping based on the fact that the |B1+|-to-phase encoding pulse for each transmit coil and off-resonance frequency applies a unique phase shift to the same underlying image. This enables joint reconstruction of all images in a BS acquisition from an augmented set of virtual receive coils.
Simulations are shown to produce accurate |B1+| maps at high acceleration factors for both Cartesian and Non-Cartesian sampling. Phantom and in vivo experiments confirm the simulation results and endorse the proposed approach. It is also shown that reconstruction accuracy can be improved using disjoint sampling patterns between acquisitions. Noise performance analysis in simulation demonstrates that disjoint sampling produces less noise amplification when compared to same sampling across all the coils. The approach is general in that it can be applied using any auto-calibrated multi coil image reconstruction method.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-03222013-113203 |
| Date | 12 April 2013 |
| Creators | Sharma, Anuj |
| Contributors | Adam 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-03222013-113203/ |
| Rights | unrestricted, 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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