An inverse approach to the calculation of elasticity maps for magnetic resonance elastography

Armando Manduca, Vinayak Dutt, David T. Borup, Raja Muthupillai, James F. Greenleaf, Richard L. Ehman

Research output: Contribution to journalConference article

8 Scopus citations

Abstract

Acoustic shear waves of low frequency can be detected and measured using a phase contrast based magnetic resonance imaging technique called MR Elastography or correlation or phase measurement based echo ultrasound techniques. Spatio- temporal variations of displacements caused by the propagating waves can be used to estimate local values of the elasticity of the object being imaged. The currently employed technique for estimating the elasticity from the wave displacement maps, the local frequency estimator (LFE), has fundamental resolution limits and also has problems with shadowing and other refraction-related artifacts. These problems can be overcome with an inverse approach using Green's function integrals which directly solve the wave equation problem for the propagating wave. The complete measurements of wave displacements as a function of space and time over the object of interest obtained by the above techniques make possible an iterative approach to inversion of the wave equation to obtain elasticity and attenuation maps. The speed of convergence of such an iterative method can be improved by using LFE as the initial guess for the object function. This article describes the proposed and evaluates the improvements over the LFE for simulated data and in-vivo breast measurements.

Original languageEnglish (US)
Pages (from-to)426-436
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3338
DOIs
StatePublished - Dec 1 1998
EventMedical Imaging 1998: Image Processing - San Diego, CA, United States
Duration: Feb 23 1998Feb 23 1998

Keywords

  • Elastography
  • Inverse problems
  • Magnetic resonance elastography
  • Shear wave imaging

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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