• Wyger M Brink and Andrew G Webb.
• Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands.
• Magn Reson Med. 2014 Apr 1; 71 (4): 1632-40.

PurposeTo improve image quality and reduce specific absorption rate in functional cardiac imaging at 3 T.MethodsTwo high permittivity dielectric pads on the anterior and posterior sides of the thorax were numerically designed and implemented using an aqueous suspension of barium titanate. The effects on the average transmit efficiency, B(1) homogeneity, reception sensitivity, and contrast-to-noise ratio were verified in vivo on a dual-transmit system with the body coil driven in conventional quadrature and radiofrequency-shimmed mode.ResultsStatistically significant improvements in average transmit efficiency, B(1) homogeneity, and contrast-to-noise ratio were measured in healthy volunteers (n = 11) with body mass indices between 20.3 and 34.9. Simulations show that no radiofrequency hot spots are introduced by the dielectric material.ConclusionHigh permittivity pads are shown to reduce specific absorption rate, improve B(1) homogeneity, and increase contrast-to-noise ratio in functional cardiac magnetic resonance at 3 T. The results presented in this work show that the current approach is more effective than dual-channel radiofrequency shimming.Copyright © 2013 Wiley Periodicals, Inc.

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