Adaptive Beamforming for Thermal Strain Imaging Using a Single Ultrasound Linear Array

Ultrasound-induced thermal strain imaging (TSI) using separate heating and imaging transducers has been used to successfully identify lipids and water-based tissues in atherosclerosis plaques. However it 1) has a limited field of view due to a narrow heating beam, 2) requires physically aligning heating and imaging beams, and 3) results in a bulky setup that limits in vivo operation. This study proposes and evaluates a new design for heating beams that can be implemented on a linear array imaging transducer with improved heating area and efficiency as compared to previous implementations. The designed heating beams were implemented with a L7-4 linear array transducer connected to a commercial ultrasound platform (Verasonics). The experiment and simulation results showed that the new design resulted in an effective heating area of approximately 1 cm lateral x 1 cm axial and a heating rate of up to 0.44 degrees C/sec.