A double‐quadrature radiofrequency coil design for proton‐decoupled carbon‐13 magnetic resonance spectroscopy in humans at 7T. Issue 2 (3rd March 2014)

• Record Type: Journal Article
• Authors: Roig, Eulalia Serés; Magill, Arthur W.; Donati, Guillaume; Meyerspeer, Martin; Xin, Lijing; Ipek, Ozlem; Gruetter, Rolf
• Is Part Of: Magnetic resonance in medicine. Volume 73:Issue 2(2015:Feb.)
• Page Start: 894
• Page End: 900
• Publication Date: 2014-03-03
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25171
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm25171-sec-0001" sec-type="section"> <title>Purpose</title> <p>Carbon‐13 magnetic resonance spectroscopy (<sup>13</sup>C‐MRS) is challenging because of the inherent low sensitivity of <sup>13</sup>C detection and the need for radiofrequency transmission at the <sup>1</sup>H frequency while receiving the <sup>13</sup>C signal, the latter requiring electrical decoupling of the <sup>13</sup>C and <sup>1</sup>H radiofrequency channels. In this study, we added traps to the <sup>13</sup>C coil to construct a quadrature‐<sup>13</sup>C/quadrature‐<sup>1</sup>H surface coil, with sufficient isolation between channels to allow simultaneous operation at both frequencies without compromise in coil performance.</p> </sec> <sec id="mrm25171-sec-0002" sec-type="section"> <title>Methods</title> <p>Isolation between channels was evaluated on the bench by measuring all coupling parameters. The quadrature mode of the quadrature‐<sup>13</sup>C coil was assessed using in vitro <sup>23</sup>Na gradient echo images. The signal‐to‐noise ratio (SNR) was measured on the glycogen and glucose resonances by <sup>13</sup>C‐MRS in vitro, compared with that obtained with a linear‐<sup>13</sup>C/quadrature‐<sup>1</sup>H coil, and validated by <sup>13</sup>C‐MRS in vivo in the human calf at 7T.</p> </sec> <sec id="mrm25171-sec-0003" sec-type="section"> <title>Results</title> <p>Isolation between channels was better than −30 dB. The <sup>23</sup>Na gradient echo images indicate a region where the field is strongly circularly polarized. The quadrature coil provided an SNR enhancement over a linear coil of 1.4, in vitro and in vivo.</p> </sec> <sec id="mrm25171-sec-0004" sec-type="section"> <title>Conclusion</title> <p>It is feasible to construct a double‐quadrature <sup>13</sup>C‐<sup>1</sup>H surface coil for proton decoupled sensitivity enhanced <sup>13</sup>C‐NMR spectroscopy in humans at 7T. <bold>Magn Reson Med 73:894–900, 2015. © 2014 Wiley Periodicals, Inc.</bold></p> </sec> </abstract>