Wave Deflector for Ultrasound-Guided Interventions

Abstract

Ultrasound guidance systems are essential tools to accompany medical needle-based interventions such as vascular access, peripheral nerve blocks and biopsies. These systems facilitate the delicate process of approaching needles to a target area through in-plane needle tip tracking. Needle-probe misalignment and false tip detection might cause serious injuries and damage to the patient. This study presents an innovative design for a wave deflector that allows for continuous in-plane needle visualization to mitigate the damage risk during surgeries. This design depends on wave reflections that take into consideration the mechanical and acoustic properties of the reflection interface and media of propagation. The deflector is 3D printed and simply attached to the ultrasound probe. An acoustic mirror is integrated inside the deflector to deviate the wave's path by 120° allowing the needle to be inserted vertically into the image plane. The deflector is filled with ballistic gel to provide a propagation medium for the acoustic waves. The deflector's image quality is assessed using the ultrasound quality assurance method which shows acceptable error margin compared to control case. Furthermore, the prototype is experimentally validated through a set of experiments conducted by 12 cardiology fellows. Twelve doctors performed twelve needle interventions each with and without using the deflector on artificial targets. The results show that the accuracy increases with trials. Moreover, the number of needed injections is improved, while the time remains fluctuating with no significant improvement. This prototype is expected to significantly reduce the risk of complications and decrease the stress on the surgeon, as the NASA TLX scores (weighted average=32) of the participants show acceptable workload with respect to the NASA scores of medical applications stated in literature.