Simulations of a birdcage coil B1+ field on a human body model for designing a 3T multichannel TMS/MRI head coil array

Lucia I. Navarro De Lara, Laleh Golestani Rad, Sergey N. Makarov, Jason Stockmann, Lawrence L. Wald, Aapo Nummenmaa

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

This article considers a new type of integrated multichannel Transcranial Magnetic Stimulator and Magnetic Resonance Imaging (TMS/MRI) system at 3T that is currently being designed. The system will enable unprecedented spatiotemporal control of the TMS-induced electric fields (Efields) with simultaneous rapid whole-head MRI acquisition to record the brain activity. A critical design question is how TMS coil elements interact with the transmit field B1+ of the volume coil integrated in 3T MRI systems. In general, the TMS coils are not designed to have any resonant characteristics at the MRI frequency, they may potentially disturb the RF field due to the eddy currents induced. This is especially a concern with a multichannel TMS setup where the subject's head will be largely covered with the stimulation coils. Therefore, we investigated this problem by computational simulations with realistic TMS coil geometries and a birdcage transmit coil in conjunction with a human body model. We compared the B1+ interaction effects of a commercially available MR-compatible TMS coil with our coil prototype. In both cases, the results show small local changes in the transmit field B1+ of the birdcage coil. Maximal Average Specific Absorption Rate (SAR) values over 1g tissue were found to be slightly lower when the TMS elements were present. We conclude that it should be feasible and safe to use the conventional body transmit coil even when an array of TMS coils is used.

Original languageEnglish (US)
Title of host publication40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2018
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages4752-4755
Number of pages4
ISBN (Electronic)9781538636466
DOIs
StatePublished - Oct 26 2018
Externally publishedYes
Event40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2018 - Honolulu, United States
Duration: Jul 18 2018Jul 21 2018

Publication series

NameProceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS
Volume2018-July
ISSN (Print)1557-170X

Other

Other40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2018
CountryUnited States
CityHonolulu
Period7/18/187/21/18

ASJC Scopus subject areas

  • Signal Processing
  • Biomedical Engineering
  • Computer Vision and Pattern Recognition
  • Health Informatics

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