On the feasibility of remote palpation using acoustic radiation force

TLDR

Acoustic remote palpation uses focused ultrasound to image local mechanical property variations by measuring tissue displacements, which are inversely proportional to tissue stiffness. The study demonstrates the feasibility of acoustic remote palpation experimentally on breast tissue phantoms and in vitro liver samples. The method applies focused ultrasound to generate localized radiation force, maps the resulting displacements with ultrasonic correlation using a single diagnostic transducer and modified imaging system, and examines how beam parameters and lesion characteristics affect displacement patterns. Displacement images correlate strongly with tissue stiffness, offering higher contrast than B-mode images, and the results suggest clinical potential for remote palpation.

Abstract

A method of acoustic remote palpation, capable of imaging local variations in the mechanical properties of tissue, is under investigation. In this method, focused ultrasound is used to apply localized (on the order of 2 mm3) radiation force within tissue, and the resulting tissue displacements are mapped using ultrasonic correlation based methods. The tissue displacements are inversely proportional to the stiffness of the tissue, and thus a stiffer region of tissue exhibits smaller displacements than a more compliant region. In this paper, the feasibility of remote palpation is demonstrated experimentally using breast tissue phantoms with spherical lesion inclusions, and in vitro liver samples. A single diagnostic transducer and modified ultrasonic imaging system are used to perform remote palpation. The displacement images are directly correlated to local variations in tissue stiffness with higher contrast than the corresponding B-mode images. Relationships between acoustic beam parameters, lesion characteristics and radiation force induced tissue displacement patterns are investigated and discussed. The results show promise for the clinical implementation of remote palpation.