Tissue Stiffness Measurement Using Vibrational Force in Medical Ultrasound Imaging System

摘要

Tumors have different mechanical vibration characteristics from those of normal tissues. The vibration magnitude is determined by both the elastic modulus and the applied vibration frequency. Tissues subject to an external vibration force undergo displacements, changing their ultrasonic speckle patterns, and thus the amount of change is highly correlated with their elastic modulus. This principle can be used to diagnose tumors which have been difficult to detect with conventional ultrasonic B-mode imaging techniques. In this paper, the vibration characteristics of lesions of various sizes and elastic moduli are assessed by simulation and experiment as a function of vibration frequency. We fabricated tissue equivalent phantoms from agar and gelatin, and acquired their experimental data sets using a 7.5 MHz linear array diagnostic ultrasonic scanner. The relationship between the detectable lesion size and the vibration frequency is explored by simulation and confirmed by experiment.