Investigating the influence of dielectric pads in 7T magnetic resonance imaging – simulated and experimental assessment

Dipole radiofrequency (RF) elements have been successfully used to compose multi-channel RF coils for ultrahigh fields (UHF) magnetic resonance imaging (MRI). As magnetic components of RF fields (B1) can be very inhomogeneous at UHF (B0≥7T), dielectric pads with high dielectric constants were propos...

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Autores principales:	Garcia Maíra M., Chaim Khallil T., Otaduy Maria C. G., Rennings Andreas, Erni Daniel, Vatanchi Maryam, Zylka Waldemar
Formato:	article
Lenguaje:	EN
Publicado:	De Gruyter 2020
Materias:	7t mri dielectric pads experiment electromagnetic simulation dipole rf coil phantom b1 homogeneity sar mri safety Medicine R
Acceso en línea:	https://doaj.org/article/6fbbf5ec4c9a4931a9165821d6d42484
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spelling	oai:doaj.org-article:6fbbf5ec4c9a4931a9165821d6d424842021-12-05T14:10:42ZInvestigating the influence of dielectric pads in 7T magnetic resonance imaging – simulated and experimental assessment2364-550410.1515/cdbme-2020-3007https://doaj.org/article/6fbbf5ec4c9a4931a9165821d6d424842020-09-01T00:00:00Zhttps://doi.org/10.1515/cdbme-2020-3007https://doaj.org/toc/2364-5504Dipole radiofrequency (RF) elements have been successfully used to compose multi-channel RF coils for ultrahigh fields (UHF) magnetic resonance imaging (MRI). As magnetic components of RF fields (B1) can be very inhomogeneous at UHF (B0≥7T), dielectric pads with high dielectric constants were proposed to improve the B1 efficiency and homogeneity [1]. Dielectric pads can be used as a passive B1 shimmimg technique thanks to inducing a strong secondary magnetic field in their vicinity. The use of such dielectric pads affect not only the B1 field but also the electric field. This in turn affects the specific absorption rate (SAR) and consequently the temperature distribution inside the patient’s body. To study these effects, a 29 cm-long transmission dipole RF coil element terminated by two meander was used for 7T MRI [2]. Using a cylindrical agarose-gel phantom, numerical and experimental results were analyzed with respect to homogeneity and amplitude of the magnetic and electric fields generated by the RF element in various configurations with and without dielectric pads. Calculated and measured B1 results were cross-checked and found to be in good agreement. When using dielectric pads B1 homogeneity and magnitude increase in regions where it was previously weak or insufficient. Calculations suggest that SAR distribution will change when using the pads.Garcia Maíra M.Chaim Khallil T.Otaduy Maria C. G.Rennings AndreasErni DanielVatanchi MaryamZylka WaldemarDe Gruyterarticle7t mridielectric padsexperimentelectromagnetic simulationdipole rf coilphantomb1homogeneitysarmri safetyMedicineRENCurrent Directions in Biomedical Engineering, Vol 6, Iss 3, Pp 24-27 (2020)
institution	DOAJ
collection	DOAJ
language	EN
topic	7t mri dielectric pads experiment electromagnetic simulation dipole rf coil phantom b1 homogeneity sar mri safety Medicine R
spellingShingle	7t mri dielectric pads experiment electromagnetic simulation dipole rf coil phantom b1 homogeneity sar mri safety Medicine R Garcia Maíra M. Chaim Khallil T. Otaduy Maria C. G. Rennings Andreas Erni Daniel Vatanchi Maryam Zylka Waldemar Investigating the influence of dielectric pads in 7T magnetic resonance imaging – simulated and experimental assessment
description	Dipole radiofrequency (RF) elements have been successfully used to compose multi-channel RF coils for ultrahigh fields (UHF) magnetic resonance imaging (MRI). As magnetic components of RF fields (B1) can be very inhomogeneous at UHF (B0≥7T), dielectric pads with high dielectric constants were proposed to improve the B1 efficiency and homogeneity [1]. Dielectric pads can be used as a passive B1 shimmimg technique thanks to inducing a strong secondary magnetic field in their vicinity. The use of such dielectric pads affect not only the B1 field but also the electric field. This in turn affects the specific absorption rate (SAR) and consequently the temperature distribution inside the patient’s body. To study these effects, a 29 cm-long transmission dipole RF coil element terminated by two meander was used for 7T MRI [2]. Using a cylindrical agarose-gel phantom, numerical and experimental results were analyzed with respect to homogeneity and amplitude of the magnetic and electric fields generated by the RF element in various configurations with and without dielectric pads. Calculated and measured B1 results were cross-checked and found to be in good agreement. When using dielectric pads B1 homogeneity and magnitude increase in regions where it was previously weak or insufficient. Calculations suggest that SAR distribution will change when using the pads.
format	article
author	Garcia Maíra M. Chaim Khallil T. Otaduy Maria C. G. Rennings Andreas Erni Daniel Vatanchi Maryam Zylka Waldemar
author_facet	Garcia Maíra M. Chaim Khallil T. Otaduy Maria C. G. Rennings Andreas Erni Daniel Vatanchi Maryam Zylka Waldemar
author_sort	Garcia Maíra M.
title	Investigating the influence of dielectric pads in 7T magnetic resonance imaging – simulated and experimental assessment
title_short	Investigating the influence of dielectric pads in 7T magnetic resonance imaging – simulated and experimental assessment
title_full	Investigating the influence of dielectric pads in 7T magnetic resonance imaging – simulated and experimental assessment
title_fullStr	Investigating the influence of dielectric pads in 7T magnetic resonance imaging – simulated and experimental assessment
title_full_unstemmed	Investigating the influence of dielectric pads in 7T magnetic resonance imaging – simulated and experimental assessment
title_sort	investigating the influence of dielectric pads in 7t magnetic resonance imaging – simulated and experimental assessment
publisher	De Gruyter
publishDate	2020
url	https://doaj.org/article/6fbbf5ec4c9a4931a9165821d6d42484
work_keys_str_mv	AT garciamairam investigatingtheinfluenceofdielectricpadsin7tmagneticresonanceimagingsimulatedandexperimentalassessment AT chaimkhallilt investigatingtheinfluenceofdielectricpadsin7tmagneticresonanceimagingsimulatedandexperimentalassessment AT otaduymariacg investigatingtheinfluenceofdielectricpadsin7tmagneticresonanceimagingsimulatedandexperimentalassessment AT renningsandreas investigatingtheinfluenceofdielectricpadsin7tmagneticresonanceimagingsimulatedandexperimentalassessment AT ernidaniel investigatingtheinfluenceofdielectricpadsin7tmagneticresonanceimagingsimulatedandexperimentalassessment AT vatanchimaryam investigatingtheinfluenceofdielectricpadsin7tmagneticresonanceimagingsimulatedandexperimentalassessment AT zylkawaldemar investigatingtheinfluenceofdielectricpadsin7tmagneticresonanceimagingsimulatedandexperimentalassessment
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Investigating the influence of dielectric pads in 7T magnetic resonance imaging – simulated and experimental assessment

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