MR Measurement of Breast Tissue's Anisotropic Mechanical Properties
Abstract
We are progressing well toward the grant's original goals. Personnel attrition and software changes have impeded progress so we have obtained a one year no-cost extension. We have been productive none the less. We have developed finite element code to simulate the displacement of tissue from low frequency harmonic vibrations. The simulations showed us several things. First, when the amplitude of the vibration is large enough to measure accurately with the MRI, the solutions become very complicated and require a partial differential equation to estimate the elasticity; estimates of elasticity that only use local data are only useful for very simple geometry with very simple boundary conditions. Second, shear waves are damped much faster than distortional waves so we have designed a vibration source capable of inducing compression and shaking rather than shear. We have designed, built and tested the device that produces wide bandwidth, high force, high amplitude displacements in an MRI magnet. The device is non-resonant so arbitrary waveforms can be achieved. We have rewritten the MR pulse sequences for the newest MRI scanner. We have developed a reconstruction routine that successfully reconstructs simulated elasticity distributions. The results are substantive progress toward the goals of this project.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1998
- Accession Number
- ADA355325
Entities
People
- John B. Weaver
Organizations
- Dartmouth College