Elastography: Elasticity Imaging Using Ultrasound with Application to Muscle and Breast <i>in Vivo</i>

TLDR

Tissue elasticity correlates with pathology, yet small or deep lesions are often undetectable by palpation or ultrasound, motivating elastography as an ultrasonic imaging technique for compliant tissues, previously demonstrated in phantom studies. The study introduces a linear‑array elastography system for in‑vivo scanning and demonstrates its feasibility through phantom experiments and preliminary breast and muscle elastograms. The system estimates local longitudinal strain from one‑dimensional ultrasonic displacements, combines it with first‑order stress estimates to quantify elastic properties, and employs a linear‑array transducer for in‑vivo imaging. Elastograms are displayed as grayscale images, and.

Abstract

Changes in tissue elasticity are generally correlated with its pathological state. In many cases, despite the difference in elasticity, the small size of a lesion or its location deep in the body preclude its detection by palpation. In general, such a lesion may or may not posses echogenic properties that would make it ultrasonically detectable. Elastography is an ultrasonic method for imaging the elasticity of compliant tissues. The method estimates the local longitudinal strain of tissue elements by ultrasonically assessing the one dimensional local displacements. This information can be combined with first order theoretical estimates of the local stress to yield a quantitative measure of the local elastic properties of tissue. The elasticity information is displayed in the form of a gray scale image called an elastogram. An experimental system for elastography in phantoms based on a single element transducer has been described previously [1]. Here we introduce a new elastography system based on a linear array transducer that is suitable for in vivo scanning. We describe tissue mimicking phantom experiments and preliminary in vivo breast and muscle elastograms confirming the feasibility of performing elastography in vivo. An elastogram of a breast containing an 8 mm palpable cancer nodule clearly shows the lesion. Elastograms and their corresponding sonograms show some similarities and differences in the depiction of tissue structures.