Development of Hydrostatic Annular Ultrasounds Transducers for Intravascular Sonoelastographic Shear Velocity Imaging

The design, fabrication, and testing of hydrostatic annular ultrasounds transducers for intravascular sonoelastographic shear velocity for imaging is presented. By using dual element piezo rings with through-blood acoustic shear waves propagation, the miniaturized hydrostatic annular ultrasound transducer was developed. The annular array was designed and fabricated using two sets of different thickness piezo-rings embedded in steel rings with fine grooves of 250 μm wide separated by a 1 mm polymer spacers, and a light backing layer of Epo-Tek 301(Epoxy Tech., Inc., Billerica, MA). Epoxy was used for backing layers, and a flexible circuit was used for interconnecting the annuli with 75 Ohm coaxial cables. One array was tested, and the results were found to be in reasonable agreement with the numerical simulation. The highest measured total acoustic pressure for pulse-echo response and the maximum displacement of PZT rings in radial direction around 19.5 MHz for this transducer was 24 kPa and 8 nm, respectively.