In vivo human head MRI at 10.5T: A radiofrequency safety study and preliminary imaging results

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

PURPOSE: The purpose of this study is to safely acquire the first human head images at 10.5T.

METHODS: To ensure safety of subjects, we validated the electromagnetic simulation model of our coil. We obtained quantitative agreement between simulated and experimental B 1 + and specific absorption rate (SAR). Using the validated coil model, we calculated radiofrequency power levels to safely image human subjects. We conducted all experiments and imaging sessions in a controlled radiofrequency safety lab and the whole-body 10.5T scanner in the Center for Magnetic Resonance Research.

RESULTS: Quantitative agreement between the simulated and experimental results was obtained including S-parameters, B 1 + maps, and SAR. We calculated peak 10 g average SAR using 4 different realistic human body models for a quadrature excitation and demonstrated that the peak 10 g SAR variation between subjects was less than 30%. We calculated safe power limits based on this set and used those limits to acquire T 2 - and T 2 ∗ -weighted images of human subjects at 10.5T.

CONCLUSIONS: In this study, we acquired the first in vivo human head images at 10.5T using an 8-channel transmit/receive coil. We implemented and expanded a previously proposed workflow to validate the electromagnetic simulation model of the 8-channel transmit/receive coil. Using the validated coil model, we calculated radiofrequency power levels to safely image human subjects.

Original languageEnglish (US)
Pages (from-to)484-496
Number of pages13
JournalMagnetic resonance in medicine
Volume84
Issue number1
DOIs
StatePublished - Jul 1 2020

Bibliographical note

Publisher Copyright:
© 2019 International Society for Magnetic Resonance in Medicine

Keywords

  • 10.5T
  • MRI
  • head imaging
  • radiofrequency safety
  • ultra-high field

PubMed: MeSH publication types

  • Journal Article
  • Research Support, N.I.H., Extramural

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