Geometric Focusing of High Frequency Shear Waves for Noninvasive High Resolution MR Elastography

Thomas J Royston¹, Temel Kaya Yasar¹, Richard L Magin¹

We combine the benefits of noninvasiveness and geometric focusing of the rapidly attenuating shear waves to extend the useful shear wave frequency range, and thus achieve very short shear wavelengths that will help in providing more localized estimates of material properties using MR elastography on in vitro tissue specimens or materials. This is accomplished by vibrating the entire sealed test tube axially, effectively using the entire inner test tube wall as an axisymmetric shear wave source that creates waves travelling radially inward. The basic theory supporting this approach is followed by a description of our experimental setup and pilot results.