### 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 language | English (US) |
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Title of host publication | Proceedings of SPIE - The International Society for Optical Engineering |

Pages | 426-436 |

Number of pages | 11 |

Volume | 3338 |

DOIs | |

State | Published - 1998 |

Event | Medical Imaging 1998: Image Processing - San Diego, CA, United States Duration: Feb 23 1998 → Feb 23 1998 |

### Other

Other | Medical Imaging 1998: Image Processing |
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Country | United States |

City | San Diego, CA |

Period | 2/23/98 → 2/23/98 |

### Fingerprint

### Keywords

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

### ASJC Scopus subject areas

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

### Cite this

*Proceedings of SPIE - The International Society for Optical Engineering*(Vol. 3338, pp. 426-436) https://doi.org/10.1117/12.310921

**An inverse approach to the calculation of elasticity maps for magnetic resonance elastography.** / Manduca, Armando; Dutt, Vinayak; Borup, David T.; Muthupillai, Raja; Greenleaf, James F; Ehman, Richard Lorne.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Proceedings of SPIE - The International Society for Optical Engineering.*vol. 3338, pp. 426-436, Medical Imaging 1998: Image Processing, San Diego, CA, United States, 2/23/98. https://doi.org/10.1117/12.310921

}

TY - GEN

T1 - An inverse approach to the calculation of elasticity maps for magnetic resonance elastography

AU - Manduca, Armando

AU - Dutt, Vinayak

AU - Borup, David T.

AU - Muthupillai, Raja

AU - Greenleaf, James F

AU - Ehman, Richard Lorne

PY - 1998

Y1 - 1998

N2 - 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.

AB - 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.

KW - Elastography

KW - Inverse problems

KW - Magnetic resonance elastography

KW - Shear wave imaging

UR - http://www.scopus.com/inward/record.url?scp=34248189898&partnerID=8YFLogxK

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U2 - 10.1117/12.310921

DO - 10.1117/12.310921

M3 - Conference contribution

AN - SCOPUS:34248189898

VL - 3338

SP - 426

EP - 436

BT - Proceedings of SPIE - The International Society for Optical Engineering

ER -