Accelerating implant RF safety assessment using a low-rank inverse update method

Peter R.S. Stijnman (Corresponding author), Janot P. Tokaya, Jeroen van Gemert, Peter R. Luijten, Josien P.W. Pluim, Wyger M. Brink, Rob F. Remis, Cornelis A.T. van den Berg, Alexander J.E. Raaijmakers

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Purpose: Patients who have medical metallic implants, e.g. orthopaedic implants and pacemakers, often cannot undergo an MRI exam. One of the largest risks is tissue heating due to the radio frequency (RF) fields. The RF safety assessment of implants is computationally demanding. This is due to the large dimensions of the transmit coil compared to the very detailed geometry of an implant. Methods: In this work, we explore a faster computational method for the RF safety assessment of implants that exploits the small geometry. The method requires the RF field without an implant as a basis and calculates the perturbation that the implant induces. The inputs for this method are the incident fields and a library matrix that contains the RF field response of every edge an implant can occupy. Through a low-rank inverse update, using the Sherman–Woodbury–Morrison matrix identity, the EM response of arbitrary implants can be computed within seconds. We compare the solution from full-wave simulations with the results from the presented method, for two implant geometries. Results: From the comparison, we found that the resulting electric and magnetic fields are numerically equivalent (maximum error of 1.35%). However, the computation was between 171 to 2478 times faster than the corresponding GPU accelerated full-wave simulation. Conclusions: The presented method enables for rapid and efficient evaluation of the RF fields near implants and might enable situation-specific scanning conditions.

Original languageEnglish
JournalMagnetic Resonance in Medicine
DOIs
Publication statusE-pub ahead of print - 30 Sep 2019

Fingerprint

Radio
Safety
Magnetic Fields
Heating
Libraries
Orthopedics

Keywords

  • FDTD
  • implant safety
  • minimization problems
  • RF Safety
  • simulations

Cite this

Stijnman, Peter R.S. ; Tokaya, Janot P. ; van Gemert, Jeroen ; Luijten, Peter R. ; Pluim, Josien P.W. ; Brink, Wyger M. ; Remis, Rob F. ; van den Berg, Cornelis A.T. ; Raaijmakers, Alexander J.E. / Accelerating implant RF safety assessment using a low-rank inverse update method. In: Magnetic Resonance in Medicine. 2019.
@article{db34df57a8044e5c8fe8cb724adf84d1,
title = "Accelerating implant RF safety assessment using a low-rank inverse update method",
abstract = "Purpose: Patients who have medical metallic implants, e.g. orthopaedic implants and pacemakers, often cannot undergo an MRI exam. One of the largest risks is tissue heating due to the radio frequency (RF) fields. The RF safety assessment of implants is computationally demanding. This is due to the large dimensions of the transmit coil compared to the very detailed geometry of an implant. Methods: In this work, we explore a faster computational method for the RF safety assessment of implants that exploits the small geometry. The method requires the RF field without an implant as a basis and calculates the perturbation that the implant induces. The inputs for this method are the incident fields and a library matrix that contains the RF field response of every edge an implant can occupy. Through a low-rank inverse update, using the Sherman–Woodbury–Morrison matrix identity, the EM response of arbitrary implants can be computed within seconds. We compare the solution from full-wave simulations with the results from the presented method, for two implant geometries. Results: From the comparison, we found that the resulting electric and magnetic fields are numerically equivalent (maximum error of 1.35{\%}). However, the computation was between 171 to 2478 times faster than the corresponding GPU accelerated full-wave simulation. Conclusions: The presented method enables for rapid and efficient evaluation of the RF fields near implants and might enable situation-specific scanning conditions.",
keywords = "FDTD, implant safety, minimization problems, RF Safety, simulations",
author = "Stijnman, {Peter R.S.} and Tokaya, {Janot P.} and {van Gemert}, Jeroen and Luijten, {Peter R.} and Pluim, {Josien P.W.} and Brink, {Wyger M.} and Remis, {Rob F.} and {van den Berg}, {Cornelis A.T.} and Raaijmakers, {Alexander J.E.}",
year = "2019",
month = "9",
day = "30",
doi = "10.1002/mrm.28023",
language = "English",
journal = "Magnetic Resonance in Medicine",
issn = "0740-3194",
publisher = "Wiley",

}

Accelerating implant RF safety assessment using a low-rank inverse update method. / Stijnman, Peter R.S. (Corresponding author); Tokaya, Janot P.; van Gemert, Jeroen; Luijten, Peter R.; Pluim, Josien P.W.; Brink, Wyger M.; Remis, Rob F.; van den Berg, Cornelis A.T.; Raaijmakers, Alexander J.E.

In: Magnetic Resonance in Medicine, 30.09.2019.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Accelerating implant RF safety assessment using a low-rank inverse update method

AU - Stijnman, Peter R.S.

AU - Tokaya, Janot P.

AU - van Gemert, Jeroen

AU - Luijten, Peter R.

AU - Pluim, Josien P.W.

AU - Brink, Wyger M.

AU - Remis, Rob F.

AU - van den Berg, Cornelis A.T.

AU - Raaijmakers, Alexander J.E.

PY - 2019/9/30

Y1 - 2019/9/30

N2 - Purpose: Patients who have medical metallic implants, e.g. orthopaedic implants and pacemakers, often cannot undergo an MRI exam. One of the largest risks is tissue heating due to the radio frequency (RF) fields. The RF safety assessment of implants is computationally demanding. This is due to the large dimensions of the transmit coil compared to the very detailed geometry of an implant. Methods: In this work, we explore a faster computational method for the RF safety assessment of implants that exploits the small geometry. The method requires the RF field without an implant as a basis and calculates the perturbation that the implant induces. The inputs for this method are the incident fields and a library matrix that contains the RF field response of every edge an implant can occupy. Through a low-rank inverse update, using the Sherman–Woodbury–Morrison matrix identity, the EM response of arbitrary implants can be computed within seconds. We compare the solution from full-wave simulations with the results from the presented method, for two implant geometries. Results: From the comparison, we found that the resulting electric and magnetic fields are numerically equivalent (maximum error of 1.35%). However, the computation was between 171 to 2478 times faster than the corresponding GPU accelerated full-wave simulation. Conclusions: The presented method enables for rapid and efficient evaluation of the RF fields near implants and might enable situation-specific scanning conditions.

AB - Purpose: Patients who have medical metallic implants, e.g. orthopaedic implants and pacemakers, often cannot undergo an MRI exam. One of the largest risks is tissue heating due to the radio frequency (RF) fields. The RF safety assessment of implants is computationally demanding. This is due to the large dimensions of the transmit coil compared to the very detailed geometry of an implant. Methods: In this work, we explore a faster computational method for the RF safety assessment of implants that exploits the small geometry. The method requires the RF field without an implant as a basis and calculates the perturbation that the implant induces. The inputs for this method are the incident fields and a library matrix that contains the RF field response of every edge an implant can occupy. Through a low-rank inverse update, using the Sherman–Woodbury–Morrison matrix identity, the EM response of arbitrary implants can be computed within seconds. We compare the solution from full-wave simulations with the results from the presented method, for two implant geometries. Results: From the comparison, we found that the resulting electric and magnetic fields are numerically equivalent (maximum error of 1.35%). However, the computation was between 171 to 2478 times faster than the corresponding GPU accelerated full-wave simulation. Conclusions: The presented method enables for rapid and efficient evaluation of the RF fields near implants and might enable situation-specific scanning conditions.

KW - FDTD

KW - implant safety

KW - minimization problems

KW - RF Safety

KW - simulations

UR - http://www.scopus.com/inward/record.url?scp=85073935656&partnerID=8YFLogxK

U2 - 10.1002/mrm.28023

DO - 10.1002/mrm.28023

M3 - Article

C2 - 31566265

AN - SCOPUS:85073935656

JO - Magnetic Resonance in Medicine

JF - Magnetic Resonance in Medicine

SN - 0740-3194

ER -