Measurement of the dynamic shear modulus of mouse brain tissue in vivo by magnetic resonance elastography

Stefan M. Atay, Christopher D. Kroenke, Arash Sabet, Philip V. Bayly

Research output: Contribution to journalArticle

89 Scopus citations

Abstract

In this study, the magnetic resonance (MR) elastography technique was used to estimate the dynamic shear modulus of mouse brain tissue in vivo. The technique allows visualization and measurement of mechanical shear waves excited by lateral vibration of the skull. Quantitative measurements of displacement in three dimensions during vibration at 1200 Hz were obtained by applying oscillatory magnetic field gradients at the same frequency during a MR imaging sequence. Contrast in the resulting phase images of the mouse brain is proportional to displacement. To obtain estimates of shear modulus, measured displacement fields were fitted to the shear wave equation. Validation of the procedure was performed on gel characterized by independent rheometry tests and on data from finite element simulations. Brain tissue is, in reality, viscoelastic and nonlinear. The current estimates of dynamic shear modulus are strictly relevant only to small oscillations at a specific frequency, but these estimates may be obtained at high frequencies (and thus high deformation rates), noninvasively throughout the brain. These data complement measurements of nonlinear viscoelastic properties obtained by others at slower rates, either ex vivo or invasively.

Original languageEnglish (US)
Article number021013
JournalJournal of Biomechanical Engineering
Volume130
Issue number2
DOIs
StatePublished - Apr 2008

Keywords

  • Brain
  • Elastography
  • MRI
  • Stiffness

ASJC Scopus subject areas

  • Biomedical Engineering
  • Physiology (medical)

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