Nuclear spin polarization <em>P</em> is a key factor in overall Magnetic Resonance (MR) sensitivity, and conventionally is of order 10<sup>-6</sup> owing to the tyranny of its induction by the strength of the detection magnetic field. But various hyperpolarization mechanisms applied externally to the detection field can temporarily increase nuclear spin polarization to near unity (<em>P</em> = 1). The resulting increased MR signal enables a variety of applications, including biomedical use of hyperpolarized (HP) contrast agents to assay cellular metabolism via Magnetic Resonance Imaging (MRI), typically <sup>13</sup>C-labeled metabolites reporting on abnormal metabolism. In this work optimization of radiofrequency (RF) coils and hyperpolarizer automation are used to increase the detection sensitivity of hyperpolarized contrast agents (HCA) and improve their production. It is shown that low-field imaging can be more sensitive than corresponding high-field detection when using RF coils optimized to the resonant frequency. The feasibility of low-field molecular imaging of <sup>1</sup>H and <sup>13</sup>C HCA with high spatial resolution (as fine as 94×94 μm<sup>2</sup>) is demonstrated with low-field 38 mm inner diameter RF coils at a static magnetic field strength <em>B</em><sub>0</sub> = 0.0475 T, achieving signal-to-noise ratios suitable for <em>in vivo</em> imaging studies.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-06092014-132843 |
| Date | 23 June 2014 |
| Creators | Coffey, Aaron Michael |
| Contributors | Kevin W. Waddell, John C. Gore, Eduard Y. Chekmenev, William A. Grissom, Wellington Pham |
| 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-06092014-132843/ |
| Rights | restrictsix, 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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