A 7T Spine Array Based on Electric Dipole Transmitters


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Abstract

Purpose:The goal of this study was to explore the feasibility of using an array of electric dipole antennas for RF transmission in spine MRI at high fields.Method:A two-channel transmit array based on an electric dipole design was quantitatively optimized for 7T spine imaging and integrated with a receive array combining eight loop coils. Using Symbol mapping, the transmit efficiency of the dipole array was compared with a design using quadrature loop pairs. The radiofrequency energy deposition for each array was measured using a home-built dielectric phantom and MR thermometry. The performance of the proposed array was qualitatively demonstrated in human studies.Results:The results indicate dramatically improved transmit efficiency for the dipole design compared with the loop excitation. A gain of up to 76% was achieved within the spinal region.Conclusion:For imaging of the spine, electric dipole–based transmitters provide an attractive alternative to the traditional loop-based design. Easy integration with existing receive array technology facilitates practical use at high fields. Magn Reson Med 74:1189–1197, 2015. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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