AN ANALYSIS OF ELASTOGRAPHIC CONTRAST-TO-NOISE RATIO

We present a theoretical formalism and simulation results that allow t he incorporation of the elastic contrast properties of tissues with si mple geometries into the elastographic noise models developed previous ly. This analysis results in the computation of the elastographic cont rast-to-noise ratio (CNRe). The CNRe in elastography is an important q uantity that is related to the detectability of a lesion or inhomogene ity. In this paper, the upper bound on the elastographic CNRe is deriv ed for both a one-dimensional (1-D) and 2-D analytic plane-strain tiss ue model. The CNRe in the elastogram depends on the contrast-transfer efficiency (CTE) for both the 1-D and 2-D geometries discussed in this paper. The 1-D model is used to characterize layered structures and t he 2-D model is derived for circular inclusion Within a background of uniform elasticity, A previously derived classical analytic solution o f the elasticity equations, for a circular inclusion embedded in an in finite medium and subjected to a uniaxial compression, is used to comp ute the upper bound of the CNRe. Monte Carlo simulations illustrate th e close correspondence between the theoretical and simulation results. (C) 1998 World Federation for Ultrasound in Medicine & Biology.