Wyger M Brink1, Andrew G Webb. 1. Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands.
Abstract
PURPOSE: To improve image quality and reduce specific absorption rate in functional cardiac imaging at 3 T. METHODS: Two 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. RESULTS: Statistically 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. CONCLUSION: High 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.
PURPOSE: To improve image quality and reduce specific absorption rate in functional cardiac imaging at 3 T. METHODS: Two 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. RESULTS: Statistically 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. CONCLUSION: High 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.
Authors: Sebastian Rupprecht; Christopher T Sica; Wei Chen; Michael T Lanagan; Qing X Yang Journal: Magn Reson Med Date: 2017-09-25 Impact factor: 4.668
Authors: Laleh Golestanirad; Leonardo M Angelone; John Kirsch; Sean Downs; Boris Keil; Giorgio Bonmassar; Lawrence L Wald Journal: IEEE Trans Microw Theory Tech Date: 2019-01-01 Impact factor: 3.599
Authors: Manushka V Vaidya; Mariana Lazar; Cem M Deniz; Gillian G Haemer; Gang Chen; Mary Bruno; Daniel K Sodickson; Riccardo Lattanzi; Christopher M Collins Journal: J Magn Reson Imaging Date: 2018-01-21 Impact factor: 4.813
Authors: Marc D Lindley; Daniel Kim; Glen Morrell; Marta E Heilbrun; Pippa Storey; Christopher J Hanrahan; Vivian S Lee Journal: Invest Radiol Date: 2015-02 Impact factor: 6.016
Authors: Manushka V Vaidya; Cem M Deniz; Christopher M Collins; Daniel K Sodickson; Riccardo Lattanzi Journal: MAGMA Date: 2017-11-06 Impact factor: 2.310
Authors: Bu S Park; Brent McCright; Leonardo M Angelone; Amir Razjouyan; Sunder S Rajan Journal: IEEE Trans Electromagn Compat Date: 2017-10 Impact factor: 2.006
Authors: Christopher T Sica; Sebastian Rupprecht; Ryan J Hou; Matthew T Lanagan; Navid P Gandji; Michael T Lanagan; Qing X Yang Journal: Magn Reson Med Date: 2019-09-10 Impact factor: 4.668