Prediction and near-field observation of skull-guided acoustic waves

TL;DR

This paper discovers and confirms the existence of skull-guided acoustic waves through near-field measurements, potentially enhancing ultrasound-based brain diagnostics and therapies by understanding skull's near-field acoustic properties.

Contribution

It provides the first experimental evidence of skull-guided acoustic waves and validates a multilayered flat plate model for their dispersion, expanding knowledge beyond far-field observations.

Findings

Confirmed existence of skull-guided acoustic waves in ex-vivo murine skulls.

Dispersion matches multilayered flat plate model predictions.

Potential to improve ultrasound brain diagnostics and therapy.

Abstract

Ultrasound waves propagating in water or soft biological tissue are strongly reflected when encountering the skull, which limits the use of ultrasound-based techniques in transcranial imaging and therapeutic applications. Current knowledge on the acoustic properties of the cranial bone is restricted to far-field observations, leaving its near-field properties unexplored. We report on the existence of skull-guided acoustic waves, which was herein confirmed by near-field measurements of optoacoustically-induced responses in ex-vivo murine skulls immersed in water. Dispersion of the guided waves was found to reasonably agree with the prediction of a multilayered flat plate model. It is generally anticipated that our findings may facilitate and broaden the application of ultrasound-mediated techniques in brain diagnostics and therapy.