ANALYTICAL MODELLING BASED ON RESONANCE SCATTERING THEORY EXPLAINING THE NEEDLE VISIBILITY INCONSISTENCY IN B-MODE ULTRASOUND

In an ultrasound-guided needle insertion, physicians should adjust a certain insertion angle and the position of the transducer to ensure that the initial point and final target are in-plane inside the imaging plane. One of the crucial problems in this interventional procedure is poor and inconsistent needle visibility in B-mode ultrasound. In this research, some potential physical parameters, i.e., ultrasound frequency, the incident angle of the ultrasound beam, needle density, and dimension, are investigated through analytical modeling based on the resonance scattering model to understand their behavior in affecting needle visibility. 25G non-echogenic needle is used as a model object and assumed as stainless-steel hollow cylinder insonified by oblique incident plane wave varied within the frequency of 0–10 MHz and incident angle of 0°–45°. The results suggest that those physical parameters simultaneously affect the occurrence possibility of the resonant modes, which eventually affect the total scattering pressure field Ps in a non-linear way. These observed behaviors in the form of the spectrum map of resonance scattering pressure amplitude can be used to adapt a more beneficial combination of those physical parameters to obtain a higher possibility of good needle visibility through practical insertion application and potential echogenic technology or adaptive beamforming.