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Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging
Purpose: The purpose of this study was to investigate the need for high-resolution detailed anatomical modeling to correctly estimate radio-frequency (RF) safety during magnetic resonance imaging (MRI). RF-induced heating near metallic implanted devices depends on the electric field tangential to th...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6232906/ https://www.ncbi.nlm.nih.gov/pubmed/30459628 http://dx.doi.org/10.3389/fphys.2018.01439 |
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author | Fujimoto, Kyoko Angelone, Leonardo M. Lucano, Elena Rajan, Sunder S. Iacono, Maria Ida |
author_facet | Fujimoto, Kyoko Angelone, Leonardo M. Lucano, Elena Rajan, Sunder S. Iacono, Maria Ida |
author_sort | Fujimoto, Kyoko |
collection | PubMed |
description | Purpose: The purpose of this study was to investigate the need for high-resolution detailed anatomical modeling to correctly estimate radio-frequency (RF) safety during magnetic resonance imaging (MRI). RF-induced heating near metallic implanted devices depends on the electric field tangential to the device (E(tan)). E(tan) and specific absorption rate (SAR) were analyzed in blood vessels of an anatomical model to understand if a standard gel phantom accurately represents the potential heating in tissues due to passive vascular implants such as stents. Methods: A numerical model of an RF birdcage body coil and an anatomically realistic virtual patient with a native spatial resolution of 1 mm(3) were used to simulate the in vivo electric field at 64 MHz (1.5 T MRI system). Maximum values of SAR inside the blood vessels were calculated and compared with peaks in a numerical model of the ASTM gel phantom to see if the results from the simplified and homogeneous gel phantom were comparable to the results from the anatomical model. E(tan) values were also calculated in selected stent trajectories inside blood vessels and compared with the ASTM result. Results: Peak SAR values in blood vessels were up to ten times higher than those found in the ASTM standard gel phantom. Peaks were found in clinically significant anatomical locations, where stents are implanted as per intended use. Furthermore, E(tan) results showed that volume-averaged SAR values might not be sufficient to assess RF safety. Conclusion: Computational modeling with a high-resolution anatomical model indicated higher values of the incident electric field compared to the standard testing approach. Further investigation will help develop a robust safety testing method which reflects clinically realistic conditions. |
format | Online Article Text |
id | pubmed-6232906 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-62329062018-11-20 Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging Fujimoto, Kyoko Angelone, Leonardo M. Lucano, Elena Rajan, Sunder S. Iacono, Maria Ida Front Physiol Physiology Purpose: The purpose of this study was to investigate the need for high-resolution detailed anatomical modeling to correctly estimate radio-frequency (RF) safety during magnetic resonance imaging (MRI). RF-induced heating near metallic implanted devices depends on the electric field tangential to the device (E(tan)). E(tan) and specific absorption rate (SAR) were analyzed in blood vessels of an anatomical model to understand if a standard gel phantom accurately represents the potential heating in tissues due to passive vascular implants such as stents. Methods: A numerical model of an RF birdcage body coil and an anatomically realistic virtual patient with a native spatial resolution of 1 mm(3) were used to simulate the in vivo electric field at 64 MHz (1.5 T MRI system). Maximum values of SAR inside the blood vessels were calculated and compared with peaks in a numerical model of the ASTM gel phantom to see if the results from the simplified and homogeneous gel phantom were comparable to the results from the anatomical model. E(tan) values were also calculated in selected stent trajectories inside blood vessels and compared with the ASTM result. Results: Peak SAR values in blood vessels were up to ten times higher than those found in the ASTM standard gel phantom. Peaks were found in clinically significant anatomical locations, where stents are implanted as per intended use. Furthermore, E(tan) results showed that volume-averaged SAR values might not be sufficient to assess RF safety. Conclusion: Computational modeling with a high-resolution anatomical model indicated higher values of the incident electric field compared to the standard testing approach. Further investigation will help develop a robust safety testing method which reflects clinically realistic conditions. Frontiers Media S.A. 2018-10-22 /pmc/articles/PMC6232906/ /pubmed/30459628 http://dx.doi.org/10.3389/fphys.2018.01439 Text en Copyright © 2018 Fujimoto, Angelone, Lucano, Rajan and Iacono. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Physiology Fujimoto, Kyoko Angelone, Leonardo M. Lucano, Elena Rajan, Sunder S. Iacono, Maria Ida Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging |
title | Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging |
title_full | Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging |
title_fullStr | Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging |
title_full_unstemmed | Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging |
title_short | Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging |
title_sort | radio-frequency safety assessment of stents in blood vessels during magnetic resonance imaging |
topic | Physiology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6232906/ https://www.ncbi.nlm.nih.gov/pubmed/30459628 http://dx.doi.org/10.3389/fphys.2018.01439 |
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