Optimum design of echogenic needles for ultrasound guided nerve block

The goal of this study is to optimize a cylindrical needle with a grooved surface for maximum backscattering to the transceiver during medical ultrasound procedures. Evaluation of backscattering performance of multiple prototype geometries with 2D time-harmonic acoustic finite element analysis was performed. Groove patterns with repeat periods determined with the guidance of the grating equation to produce constructive interference showed very strong and sharp backscattering peaks, but only at specific isonification angles. Optimum depths for the groove patterns with groove periods defined by the grating equation were found. A search on possible geometries was performed, varying the design variables of groove period and groove depth, with an objective function designed to select geometries that performed well at multiple isonification angles.