An improved trap design for decoupling multinuclear RF coils.

Autor: Meyerspeer M; LIFMET, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria; MR Centre of Excellence, Medical University of Vienna, Austria., Serés Roig E, Gruetter R, Magill AW
Jazyk: angličtina
Zdroj: Magnetic resonance in medicine [Magn Reson Med] 2014 Aug; Vol. 72 (2), pp. 584-90. Date of Electronic Publication: 2013 Sep 04.
DOI: 10.1002/mrm.24931
Abstrakt: Purpose: 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 (1)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 (1)H blocking.
Methods: 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 (1)H and (13)C measurements in a 7T human scanner.
Results: 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.
Conclusion: 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.
(Copyright © 2013 Wiley Periodicals, Inc.)
Databáze: MEDLINE
Externí odkaz: