A 24fr Femoral Introducer Sheath Featured by an Advanced Forward-Looking Matrix Transducer for Enhanced 2D Imaging and 3D Guidance

This work details the design and fabrication of a 24 Fr ultrasound catheter sheath with >90° mechanical steering and forward-looking imaging for minimally invasive cardiac procedures. A 16 Fr lumen accommodates therapy catheters, while a 2D annular array provides real-time imaging: wide-view 3D for navigation and high-res 2D for precise monitoring. Field-II simulations were performed to optimize the array—256 trapezoidal elements (7.5 MHz) arranged in four rings—maintaining a 22.5 Fr outer diameter. The fabrication involved a piezocomposite stack on a flexible PCB integrated into the sheath. In vitro testing using a therapy catheter and a CIRS054 phantom demonstrated potential for both 3D guidance and high-resolution 2D imaging, meeting application requirements. This advanced sheath aims to improve cardiac surgery workflow, eliminating the need for an auxiliary ultrasound imaging pathway and providing 3D real-time information while reducing fluoroscopy. This solution was further validated in a porcine preclinical cardiac interventional procedure.