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Improved image quality and reduced power deposition in the spine at 3 T using extremely high permittivity materials
Author(s) -
Koolstra Kirsten,
Börnert Peter,
Brink Wyger,
Webb Andrew
Publication year - 2018
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.26721
Subject(s) - image quality , specific absorption rate , computer science , permittivity , magnetic resonance imaging , quality (philosophy) , lead zirconate titanate , power (physics) , materials science , dielectric , telecommunications , image (mathematics) , physics , artificial intelligence , optoelectronics , medicine , radiology , ferroelectricity , quantum mechanics , antenna (radio)
Purpose To explore the effect of using extremely high permittivity (ε r ∼1,000) materials on image quality and power requirements of spine imaging at 3 T. Theory and Methods A linear array of high permittivity dielectric blocks made of lead zirconate titanate (PZT) was designed and characterized by electromagnetic simulations and experiments. Their effect on the transmit efficiency, receive sensitivity, power deposition, and diagnostic image quality was analyzed in vivo in 10 healthy volunteers. Results Simulation results showed that for quadrature mode excitation, the PZT blocks improve the transmit efficiency by 75% while reducing the maximum 10g average specific absorption rate (SAR 10 ) by 20%. In vivo experiments in 10 healthy volunteers showed statistically significant improvements for the transmit efficiency, and image quality. Compared to active radiofrequency shimming, image quality was similar, but the required system input power was significantly lower for quadrature excitation using the PZT blocks. Conclusion For single‐channel transmit systems, using high permittivity PZT blocks offer a way to improve transmit efficiency and image quality in the spine. Results show that the effect, and therefore optimal design, is body mass index and sex specific. Magn Reson Med 79:1192–1199, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.