An improved trap design for decoupling multinuclear RF coils. Issue 2 (4th September 2013)

• Record Type: Journal Article
• Authors: Meyerspeer, Martin; Roig, Eulalia Serés; Gruetter, Rolf; Magill, Arthur W.
• Is Part Of: Magnetic resonance in medicine. Volume 72:Issue 2(2014:Aug.)
• Page Start: 584
• Page End: 590
• Publication Date: 2013-09-04
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.24931
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm24931-sec-1001" sec-type="section"> <title>Purpose</title> <p>Multinuclear magnetic resonance spectroscopy and imaging require a radiofrequency probe capable of transmitting and receiving at the proton and non‐proton frequencies. To minimize coupling between probe elements tuned to different frequencies, LC (inductor‐capacitor) traps blocking current at the <sup>1</sup>H frequency can be inserted in non‐proton elements. This work compares LC traps with LCC traps, a modified design incorporating an additional capacitor, enabling control of the trap reactance at the low frequency while maintaining <sup>1</sup>H blocking.</p> </sec> <sec id="mrm24931-sec-1002" sec-type="section"> <title>Methods</title> <p>Losses introduced by both types of trap were analysed using circuit models. Radiofrequency coils incorporating a series of LC and LCC traps were then built and evaluated at the bench. LCC trap performance was then confirmed using <sup>1</sup>H and <sup>13</sup>C measurements in a 7T human scanner.</p> </sec> <sec id="mrm24931-sec-1003" sec-type="section"> <title>Results</title> <p>LC and LCC traps both effectively block interaction between non‐proton and proton coils at the proton frequency. LCC traps were found to introduce a sensitivity reduction of 5±2%, which was less than half of that caused by LC traps.</p> </sec> <sec id="mrm24931-sec-1103" sec-type="section"> <title>Conclusion</title> <p>Sensitivity of non‐proton coils is critical. The improved trap design, incorporating one extra capacitor, significantly reduces losses introduced by the trap in the non‐proton coil. Magn Reson Med 72:584–590, 2014. © 2013 Wiley Periodicals, Inc.</p> </sec> </abstract>