We successfully adapted and applied principles from elastography and harmonic imaging from diagnostic ultrasound imaging to estimating elastic nonlinearity parameters in rocks, which are sensitive to pore structure changes and fluid content variations. Because diseased tissue has very different microstructure than healthy tissue these nonlinear parameters may provide a diagnostic benefit if the parameters can be quantified and validated. In our work on sandstone samples we were able to probe, magnify, and quantify extremely subtle nonlinear behavior in rocks, which are dominated by linear elasticity. Since rocks have much lower degrees of elastic nonlinearity as compared to tissue, we anticipate that our new measurement and parameter estimation methods for rocks will benefit the medical imaging field by potentially providing robust quantitative diagnostics for tissue characterization. Several obstacles remain: how to adapt our transmission mode measurement method into a pulse-echo (or reflection seismology) type geometry, and how to validate that the measured nonlinear parameters are both sensitive to microstructure changes and provide a reliable indicator for diagnosis. We present results from some simple experiments on sandstone samples to show the effect of changing microstructure on the nonlinear sensitivity and discuss a possible analysis method using higher harmonics rather than time of flight transmission measurements.
Presentation Date: Tuesday, October 16, 2018
Start Time: 8:30:00 AM
Location: 211A (Anaheim Convention Center)
Presentation Type: Oral
