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ORCID

http://orcid.org/0000-0003-0605-0239

Date of Award

Summer 8-15-2019

Author's School

School of Engineering & Applied Science

Author's Department

Mechanical Engineering & Materials Science

Degree Name

Doctor of Philosophy (PhD)

Degree Type

Dissertation

Abstract

Accurate mechanical properties of the intact, living brain are essential for modeling traumatic brain injury (TBI). However, the properties of brain tissue in vivo have traditionally been measured in ex vivo samples. Magnetic resonance elastography (MRE) can be used to measure motion and estimate material properties of soft tissues in vivo, but MRE typically assumes tissue isotropy and homogeneity. The objective of this thesis is to improve MRE of soft tissue, like the brain, by developing and evaluating methods for in vivo estimation of heterogeneous, anisotropic properties. This was achieved through pursuit of the following aims: (1) quantifying the differences between in vivo and ex vivo brain tissue, thereby clarifying the need for in vivo measurements; (2) introducing and applying a new approach to anisotropic MRE, using data obtained during external actuation of the porcine brain in vivo, which highlighted the need for new actuation methods; and (3) developing and evaluating a method for anisotropic property estimation using MRE with actuation by harmonic focused ultrasound (FUS). This research has led to new methods for anisotropic MRE, and improved material property estimates of the brain and other soft tissues.

Language

English (en)

Chair

Philip V. Bayly

Committee Members

Hong Chen, Joel R. Garbow, J. Mark Meacham, Ruth J. Okamoto,

Comments

Permanent URL: https://doi.org/10.7936/3t9y-yn91

Available for download on Tuesday, September 01, 2020

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