Vibroacoustic signatures: proof of concept for simple material characterization during needle interventions

This proof of concept investigates the potential of vibroacoustic signals, originating from a needle tip during puncturing, as a method to differentiate ex vitro materials based on their structural characteristics. The main research question is whether the number and distribution of amplitude events in vibroacoustic waveforms correlates with the material structure, offering a feasible approach for a future real-time tissue differentiation in minimally invasive procedures.

Two types of synthetic foams with different air pocket densities were punctured using a standard Quincke lumbar needle with cutting bevel. Vibroacoustic signals were recorded during the puncture, and the number of amplitude events detected per unit distance was analyzed. The structural differences of the foams were quantified by counting the number of air pockets per unit length. Part of the study was to also consider the impact of puncture / insertion speed on the signal characteristics.

A significant correlation was observed between the air pocket density of the foams and the number of detected events per unit distance. The foam with a higher air pocket density produced more detected events compared to the one with a lower density. Insertion speed of the needle did not significantly impact the number of detected events.

The findings demonstrate that vibroacoustic signals hold information that allows the differentiation of materials based on their structural properties, laying the foundation for further research into their application in real-time tissue differentiation. Integrating vibroacoustic sensing into minimally invasive procedures could provide valuable additional information about tissue composition and integrity, potentially improving surgical precision in procedures such as tumor biopsies. Further research is needed to validate these findings with biological tissues and refine the technology for clinical use.