Surface Texturing Design to Enhance Echogenicity of Biopsy Needles During Endoscopic Ultrasound Imaging

The ultrasonic visibility of a biopsy needle tip is of critical importance for the success and safety of endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) procedures. The aim of this study was to design a surface topology, in silico, which enhances the ultrasound visibility of a needle by controlling and optimising the direction of the reflections. Topographic enhancements to needle surface redirect scattered waves back to the transducer to enhance needle visibility, or "echogenicity." Echogenicity enhancement is demonstrated across insonification angles of 30°-90° on full-length scale of biopsy needles used in practice. By applying a textured surface across the full length of the needle surface, the signal being returned to the transducer can be tripled from that of a constant periodic dimple echogenic surface and seven times that of an untextured flat surface. Our first principles model provides a quantitative insight to echogenicity and its enhancement. The model allows in silico design of needles for USG-FNA and biopsy with enhanced echogenicity and consequent improvement in visibility, including but not limited to needle tip area.