Our research focuses on advanced ultrasound techniques that interrogate the mechanical properties of tissue. For millenia, it has been known that the mechanical stiffness of tissue changes during the onset of disease, and physicians have utilized manual palpation to qualitatively examine the well-being of patients. While a powerful technique, palpation is limited in that it can only be applied to relatively large, superficial tissues that are accessible to the physician’s touch, and the technique is highly subjective. However, recent advances in medical imaging technology, specifically ultrasound, have enabled a form of virtual palpation that has revolutionized the way physicians can interrogate mechanical properties of tissue.
Virtual palpation is performed by deforming tissue with acoustic radiation force (ARF) and utilizing ultrasound to monitor the tissue deformation. ARF is a phenomenon associated with sound waves traveling through an attenuating and/or scattering medium whereby part of the wave’s energy is converted to a unidirectional body force that displaces the propagating medium. Although the displacements are very small (microns) and are generally imperceptible to the patient, ultrasound is very good at watching things move and can measure these small deformations with relatively high accuracy. Viscoelastic information can be inferred and/or measured in the tissue.