<title>Nonrigid motion estimation of ultrasound image sequences using an adaptive deformable mesh</title>

Abstract

By exploiting the correlation of ultrasound speckle patterns that result from scattering by underlying tissue elements, 2D tissue motion can be theoretically recovered by tracking the apparent movement of the speckle patterns. Speckle tracking, however, is an ill-posed inverse problem because of temporal decorrelation of the speckle patterns and the inherent low signal-to-noise ratio of medical ultrasonic images. This paper investigates the use of an adaptive deformable mesh for non-rigid tissue motion recovery from ultrasound images. The nodes connecting the mesh elements are allocated adaptively to stable speckle patterns that are less susceptible to temporal decorrelation. We use the approach of finite element analysis in manipulating the irregular mesh elements. A novel deformable block matching algorithm, making use of a Lagrange element for higher-order description of local motions, is proposed to estimate a non-rigid motion vector at each node. In order to ensure that the motion estimates are admissible to a physically plausible solution, the nodal displacements are regularized by minimizing the strain energy of the mesh deformations. Experiments based on ultrasound images of muscle contraction and on computer simulations have shown that the proposed algorithm can successfully track non-rigid displacement fields.

<title>Correlation-tracking strain estimator for elastography</title>

“…Another group of methods includes approaches that correct for non-axial motion 28,29 and a method for estimation and correction of lateral tissue movement using a sophisticated interpolation algorithm 30 . Deformable mesh algorithms 31,32 have recently been developed for complex ultrasonic motion analysis. These computationally-intensive methods may be able to track complex motions.…”

Análise de Movimento Não Rígido em Visão por Computador

“…Também em [41] são utilizadas malhas elásticas adaptativas para compressão, restauração e representação de imagens. Em [42] são também utilizadas malhas adaptativas em imagens de ultrasons para o seguimento de movimento não rígido, segundo princípios físicos pela utilização do método dos elementos finitos.…”

Emerging Ultrasound Technologies for Early Markers of Disease

“…Approaches to estimate and correct for non-axial tissue motion have been developed [42][43][44]. Deformable-mesh algorithms recently have been applied to complex, ultrasonic-motion analysis for tracking complex displacements; these algorithms may facilitate handheld applications [45,46]. When linear arrays are used for compression, azimuthal motion can be reduced by mechanically confining the tissue.…”